service manual - justanswer...this symbol →indicates a change since the last issue. safety...

TABLE OF CONTENTSPage

SAFETY CONSIDERATIONS ...................................................2INTRODUCTION ........................................................................2UNIT IDENTIFICATION ...........................................................2PRODUCT OFFERING ..............................................................4FAN MOTOR SPEED TAPS .....................................................4FA4A, FB4A, FC4B, FF1D, FH4A, AND FX4ACIRCUIT BOARD FUNCTION AND TROUBLESHOOTING— CES013003-00 and -01 PCB...............................................2-7• Printed Circuit Board Component Layout and Description.......2• Unit Functions ............................................................................2• Troubleshooting PCB ..................................................................5CIRCUIT BOARD FUNCTION AND TROUBLESHOOTING

— HK61GA001 and HK61GA003 PCB.........................8-19• Printed Circuit Board Component Layout and Description.......8• PCB Component Functions.........................................................9• Troubleshooting PCB ................................................................11ELECTRIC HEATER FUNCTION

AND TROUBLESHOOTING ..............................................19• Description of Electric Heater Components.............................19• Troubleshooting KFA, KFB, KFC, and KFD Series

Electric Heaters.......................................................................20FAN COIL DESCRIPTION

AND TROUBLESHOOTING — FK4B .......................20-27• Integrated Controls and Motor (ICM2) ....................................20• PCB Layout and Description ....................................................20• Sequence of Operation ..............................................................21• Easy Select Configuration Taps................................................22• Troubleshooting PCB ................................................................24• Troubleshooting ICM2 ..............................................................26• Condensed Version of Troubleshooting FK4B Motorand Controls ...............................................................................26

• Accessories ................................................................................27FAN COIL DESCRIPTION

AND TROUBLESHOOTING — FK4C, FV4A ...........28-34• Integrated Controls and Motor (ICM2) ....................................28• PCB Layout and Description ....................................................28• Sequence of Operation ..............................................................28• Easy Select Configuration Taps................................................30• Troubleshooting PCB ................................................................32• Troubleshooting ICM2 ..............................................................34• Condensed Version of Troubleshooting

FK4C, FV4A Motor and Controls .........................................34• Accessories ................................................................................34THERMOSTATIC EXPANSION VALVES (TXV) ..............35• Problems Affecting TXV ..........................................................36PISTON BODY CLEANING OR REPLACEMENT ............36LIQUID TUBE STRAINER .....................................................36FA, FB, FC, FK COIL/CONDENSATE PAN

REMOVAL AND REPLACEMENT ..................................36• A-Coil Units ..............................................................................36• Slope Coil Units ........................................................................37FX, FV COIL/CONDENSATE PAN REMOVAL

AND REPLACEMENT ........................................................38

CARE AND MAINTENANCE .................................................39• Filter Assembly .........................................................................39• Cooling Coil, Drain Pan, and Condensate Drain .....................39• Blower Motor and Wheel .........................................................39FF1A/FF1B/FF1C SERVICE AND

TROUBLESHOOTING ..................................................40-42• Fan Motor ..................................................................................40• Electric Heater Service..............................................................40• Cleaning or Replacing Refrigerant Flow-Control Device .......40• Liquid Tube Strainer .................................................................40• Sequence of Operation ..............................................................40• Care and Maintenance...............................................................40

FD3A SERVICE AND TROUBLESHOOTING ...............44-45• Fan Motor ..................................................................................44• Electric Heater Service..............................................................44• Cleaning or Replacing Refrigerant Flow-Control Device .......44• Liquid Tube Strainer .................................................................44• Care and Maintenance...............................................................45FG3A SERVICE AND TROUBLESHOOTING ...............45-46• Service .......................................................................................45• Maintenance...............................................................................46FA4A, FB4A, FC4B, FX4A SMART HEAT CIRCUIT

BOARD FUNCTION AND TROUBLESHOOTING ..46-50• PCB Component Layout, Description, and Function...............46• Unit Functions ...........................................................................46• Smart Heat Operation................................................................47• Electrical Operating Sequences and Troubleshooting..............48PURON® (R-410A) QUICK REFERENCE GUIDE .............50

Fig. 1—Typical Fan CoilA98023

Service Manual

RESIDENTIAL FAN COIL UNITS

Cancels: SM03-4 SM03-56-99

—1—

This symbol→ indicates a change since the last issue.

SAFETY CONSIDERATIONSImproper installation, adjustment, alteration, service, maintenance,or use can cause explosion, fire, electrical shock, or otherconditions which may cause personal injury or property damage.Consult a qualified installer, service agency, or your distributor orbranch for information or assistance. The qualified installer oragency must use factory-authorized kits or accessories whenmodifying this product. Refer to the individual installation instruc-tions packaged with the kits or accessories for detailed informa-tion.Follow all safety codes. Wear safety glasses and work gloves. Usequenching cloth for brazing operations. Have fire extinguisheravailable. Read these instructions thoroughly and follow allwarnings or cautions attached to the unit. Consult local buildingcodes and National Electrical Code (NEC) for special installationrequirements.It is important to recognize safety information. This is thesafety-alert symbol . When you see this symbol on the unit or ininstructions and manuals, be alert to the potential for personalinjury.Understand the signal words DANGER, WARNING, and CAU-TION. These words are used with the safety-alert symbol. DAN-GER identifies the most serious hazards whichwill result in severepersonal injury or death. WARNING signifies hazards whichcould result in personal injury or death. CAUTION is used toidentify unsafe practices whichwould result in minor personalinjury or product and property damage.

CAUTION: Puron (R-410A) systems operate at higherpressures than R-22 systems. Do not use R-22 serviceequipment or components on R-410A equipment. Ensureservice equipment is rated for R-410A.

INTRODUCTIONThe "F" series fan coil units are designed for flexibility in a varietyof applications, meeting upflow, horizontal, or downflow require-ments. Units are available in 1-1/2 through 5 ton nominal coolingcapacities. Factory-authorized, field-installed electric heater pack-ages are available in 3 through 30 kilowatts.

WARNING: Before installing or servicing fan coil,always turn off all power to unit. There may be more than1 disconnect switch. Turn off accessory heater power ifapplicable. Electrical shock can cause personal injury ordeath.

UNIT IDENTIFICATIONThe 16 position numbering chart allows identification of allavailable fan coil units. (See Fig. 2.)

FA4A, FB4A, FC4B, FF1D, FH4A, AND FX4ACIRCUIT BOARD

FUNCTION AND TROUBLESHOOTINGCES0130003-00 and -01 PCBThis section of the service manual describes the CESO130003-00and -01 PCB by examining the functional operation of the PCBcomponents.

I. PRINTED CIRCUIT BOARD (PCB) COMPONENTLAYOUT AND DESCRIPTION

Layout of the actual PCB is depicted in Fig. 3A.

1. The low-voltage stripped leads are used to connect the 24-vside of transformer to indoor thermostat and outdoorsection.

2. A 5-amp fuse is used to protect the low-voltage transformersecondary.

3. The fan relay is controlled by thermostat and turns fan onand off.

4. A plug is used as the connection for PCB power and electricheaters. Note the pin numbers on plug.

5. A time-delay relay circuit keeps fan motor running forapproximately 90 sec after G is de-energized. The time-delay can be defeated by cutting jumper JW1.

II. UNIT FUNCTIONS

A. Transformer

1. Proper Wiring of Transformer Primary or High Side

Yellow wire from Molex plug is wired to C terminal ontransformer and black wire from PCB relay (normally-open) terminal is wired to 208v or 230v terminal ontransformer. Units are factory wired at 230v terminal.

2. Proper Wiring of Transformer Secondary or 24-v Side

Red wire of transformer is wired to T terminal on PCB andbrown wire of transformer is wired to C terminal on PCB.

NOTE: T terminal on PCB is used to protect transformer. Tterminal is connected through the fuse to R terminal on PCB.

B. Indoor Fan

1. Wiring (See Fig. 3B for FF1D typical wiring diagram.)

Indoor fan motor yellow lead is wired to C terminal ontransformer. The red, blue, or black speed lead is wired toSPT terminal on fan relay part of PCB. Units are factorywired on medium speed (blue lead connected).

NOTE: Unused fan speed leads must be capped or taped off toprevent direct short to cabinet surface.

2. Functional Control

a. Thermostat and Relay Control

When thermostat calls for the fan in cooling, heat pump,heating, or fan-only mode, a 24-vac signal is sent torelay. This causes the relay to close its normally-opencontacts, turning on fan. When thermostat no longer callsfor the fan, the signal sent to relay is turned off and relayopens causing fan to turn off after a 90-sec fan-off delay.

b. Sequencer/Electric Heat Relay Interlock

The fan will also operate whenever there is a call forelectric heat, even if fan relay is not energized. Thishappens because fan is interlocked with first stage ofelectric heat through the normally-closed contact of fanrelay.

NOTE: The fan interlock is only connected to first stage electricheat W2. W3 and E do not contain an interlock with fan. Seeoutdoor thermostat Installation Instructions when electric heatstaging is desired.

C. Electric Heat

NOTE: Models FF1A/FF1B/FF1C use sequencers for electricheat. Model FF1D uses DC rectified relays for electric heat.(See Fig. 3C.)

When thermostat calls for electric heat, a 24-vac signal is sent tosequencer/heat relay through W2, causing first stage to turn on.W3 and E also receive signal if wired in with W2. The signal sentto W2 causes first stage to turn on. If W3 and E are not wired toW2, the sequencers/heat relays can be controlled individually tostage additional electric heat. The sequence control is described inthe following section:

—2—

Fig

.2—

Fan

Coi

l16-

Pos

ition

Num

berin

gS

yste

mA

9811

4

2nd

Pos

ition

—F

an C

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A -

RN

CB

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ard

C -

Del

uxe

D -

Fur

red

in, C

ased

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Fur

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hrou

gh th

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Com

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otor

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or, P

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Sta

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Un

it S

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2 -

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Upf

low

/Dow

nflo

w

Air

flo

w

018

(11 ⁄

2 T

on)

024

(2 T

on)

001

(Mul

ti T

ons)

002

(Mul

ti T

ons)

Etc

.Co

olin

g S

ize

10th

, 11t

h, 1

2th

Pos

ition

s—F

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oil

005

010

Etc

.

Hea

tin

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ize

(KW

)

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Pos

ition

—F

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oil

A -

Sta

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dB

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arF

- S

ingl

e P

iece

Co

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ype

5th

Pos

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—F

an C

oil

A -

115

-1-6

0N

- 2

08/2

30-1

-60

S -

230

-1-5

0

Ele

ctri

cal

F -

Fan

Coi

l

Typ

e o

f U

nit

A -

Orig

inal

B -

Sec

ond

Ser

ies

Maj

or

Ser

ies

A -

Orig

inal

Min

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Ser

ies

A -

Sta

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nit

Var

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Com

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on

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12

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1213

1415

16

—3—

TABLE 1—PRODUCT OFFERING

MODEL UNIT SIZE DESCRIPTION CABINETFA4ANF 018-060 Multipoise Single PieceFB4ANB 042-070 Multipoise ModularFB4ANF 018-060 Multipoise Single Piece

FB4ASB 042-060 Multipoise50 Hz Modular

FB4ASF 018-060 Multipoise50 Hz Single Piece

FC4BNB 042-070 Multipoise ModularFC4BNF 024-060 Multipoise Single PieceFD3ANA 018-030 Horizontal Single Piece

FF1A/FF1B/FF1C/FF1D 018-030 Vertical Single PieceFG3ANA 024, 036, 048, 060 Horizontal/Small Commercial Single PieceFH4ANB 003, 004 Multipoise ModularFH4ANF 001-004 Multipoise Single PieceFK4CNB 006 Multipoise ModularFK4CNF 001-005 Multipoise Single PieceFX4ANF 030-048 Multipoise Single PieceFX4ANB 060 Multipoise ModularFV4ANF 002, 003, 005 Multipoise Single PieceFV4ANB 006 Multipose Modular

NOTE: Multipoise units are approved for upflow, downflow, and horizontal left and right applications.

TABLE 2—PSC FAN MOTOR SPEED TAPS

MODEL UNITSIZENUMBER OF

SPEEDSHIGH

SPEEDMEDIUMSPEED

LOWSPEED COMMON

FA4A 018-036 2 Black — Blue YellowFA4A 042-060 3 Black Blue Red YellowFB4A 018-070 3 Black Blue Red YellowFC4B 024-070 3 Black Blue Red YellowFD3A 018-030 2 Black — Red Yellow

FF1A/FF1B/FF1C/FF1D 018-030 2 Black — Red Violet**FG3A 024, 036, 048, 060 1* — — — —FH4A 001-004 3 Black Blue Red YellowFX4A 030-060 3 Black Blue Red Yellow

*Belt drive.→**Yellow on FF1D

Fig. 3A—Fan Coil Printed-Circuit BoardA97020

LOWVOLTAGEFUSE

FAN RELAY

FUSE

PCB BLOCK WIRING

TIMEDELAY

NO

G R T C

NC

SPT

®

®

1005

-83-

161A

CP

C-E

94

V-0

1005

-161

LR40061

CE

SO

1300

03-0

1

HS

CI

5 A

MP

TR

GC

C

T

G

R

SP

T

K1

U1

R7R9R10

C8

C7

R2R3C3R6

R11

C4

C6

C5R8

R5R4

Q1

C1C2

F1

JW1

R1Z1

D2

D1

NO

NC

FA

N

RE

LAY

—4—

1. W2

When thermostat sends a signal to W2, a 24-vac signal isapplied across sequencer/relay number 1, causing it toclose. When sequencer/relay number 1 closes, first stage ofelectric heat is energized. In straight electric heat, fan is alsoenergized through the normally-closed contacts of fan relay.In cooling, heat pump, or manual fan mode, fan will alreadybe running since fan relay would have been energized.When thermostat stops calling for electric heat, the 24-vacsignal to sequencer/relay number 1 turns off and sequenceropens after a delay of 60 to 90 sec. Heaters equipped withrelays will be de-energized immediately. Whensequencer/relay opens, first stage of heat turns off alongwith fan, providing thermostat is not calling for the fan.

2. W3

When a signal is sent to W3, a 24-vac signal tosequencer/relay number 2 causes it to close, with secondstage of electric heat turning on. The 24-vac signal appliedto sequencer/relay number 1 causes fan to operate. Timingis such that sequencer/relay number 1 will turn on beforesequencer/relay number 2. When signal to W3 is turned off,sequencer/relay number 2 opens. If W2 is also satisfied,first stage of electric heat and fan will also turn off,providing thermostat is not calling for the fan.

3. E

When thermostat sends a signal to E, a 24-vac signal is sentto sequencer/relay number 3. The 24-vac signal applied tosequencer/relay number 3 turns on third stage of electricheat. The 24-vac signal applied to sequencer/relay number1 turns on first stage of electric heat and fan. Whenthermostat stops calling for electric heat, the signal tosequencers/relays 1, 2, and 3 are turned off, andsequencers/relays open. This causes electric heat to turn offwith fan providing thermostat is not calling for the fan.

NOTE: Electric heaters are factory wired with all stages tiedtogether. If independent staging is desired, consult outdoor ther-mostat installation instructions, or corporate thermostat instruc-tions.

III. TROUBLESHOOTING THE PRINTED-CIRCUITBOARD

Use wiring schematics shown in Fig. 4 and 5 as a guide introubleshooting PCB unless otherwise noted.

A. If Fan Will Not Turn On from Thermostat:

IF THERE IS NO HIGH VOLTAGE TO TRANSFORMER:

1. Check plug/receptacle connection. This supplies powerfrom heaters to PCB Fan Relay. Be sure plug is connectedproperly.

Fig. 3B—FF1D Typical Wiring DiagramA98229

SEE NOTE #7

F1

NONCSPT

OUTDOORUNIT

G

PCB BLK

C

INDOOR THERMOSTAT

BARRIER

CT

RFR

NOTES:

SEE RATING PLATE FOR VOLTS & HERTZ

DISCONNECT PER NEC

FIELD POWER WIRINGCOOLING CONTROLS

ELECTRIC HEAT

230V208V

BRN

REDTRAN

COM

GRN/YELGND

YEL

LO

HI

COM

RED

YELBLK FM

BRN BRN

CAP

RELAY 122 VDC COIL

R E C

SCHEMATIC DIAGRAM

COMPONENT ARRANGEMENT

CAUTION:

ATTENTION:NOT SUITABLE FOR USE ON SYSTEMS EXCEEDING 150V TO GROUND

NE CONVIENT PAS AUX INSTALLATIONS DE PLUS DE 150 V A LA TERRE

COM

208 V230 V

TRANRED

24 V

BRN

GND

NCNO

SPTFR

TC

1RG

PCB

F

L2 L1DISC

60A 60A

RED-LOW

BLK-HI

GRN/YEL-GND

FM BRNBRN

YEL-COM

FAN MOTOR THERMALLY PROTECTED

CAPGND

SEE NOTE #5

LEGEND

RED

ORNVIO

GND

2

HTR2 BLK8

LS26

HTR1 BLK 4LS1

RELAY 1YEL BLK

SEE NOTE #1

BLK

SYSTEM TRANSFORMER: 40.0VAFAN COIL/HEATER: 8.4VA

REMAINING VA AVAILABLE: 31.6VA

REC0 1

28 64

RELAY 1

CAP CAPACITORCOM COMMON

F FUSEFM FAN MOTOR

FIELD POWER WIRINGFR PCB FAN RELAY

EQUIPMENT GROUNDGND

SPT FAN SPEED TAP LOCATION

HTR HEATERLS LIMIT SWITCH

MARKED TERMINALPLUG AND RECEPTACLE

PCB PRINTED CIRCUIT BOARDREC RECTIFIER

TRAN TRANSFORMERUNMARKED TERMINAL

R W G

324494-101 REV. A

1. Use copper wire (75¡c min) only between disconnect switch and unit.2. To be wired in accordance with nec and local codes.3. If any of the original wire, as supplied, must be replaced, use the same or

equivalent type wire.4. Replace low voltage fuse with no greater than 5 AMP fuse.5. (2) Speed Motor uses HI (BLK) and LOW (RED).6. Smaller heaters will have fewer components.7. Connect R to R, G to G, etc., see outdoor instructions for details.8. Cooling controls wiring not used with electric heaters.

HTR HTR

LS LS

DISC DISCONNECT

YEL

YEL

BLUBLK

BRNRED

GRY

GRY

ORN

YEL BLK

DIS

C

DIS

CBLU

BLK

DIS

C

YEL

DIS

C

VIO

BLK

SEE

NO

TE #

8

SEE

NO

TE #

8

YEL

L1

SEE NOTE #6

L1 L2 L2

MINIMUM MOTOR SPEED SELECTIONFAN COIL SIZE

MOTOR SPEED ONE HTRMOTOR SPEED TWO HTR

LOLO LO

LO LOLO

018 024 030

ROTATION

This compartment must be closed except when servicing.

—5—

2. Check sequencer/relay number 1 and plug wiring. Yellowwire should be connected to pin number 9 of plug and tolimit switch. Black wire should be connected to pin number7 of plug and to sequencer/relay number 1.

3. Check field power leads L1 and L2. If these are notreceiving power, system cannot function.

IF TRANSFORMER HAS HIGH VOLTAGE APPLIED TO IT:

1. Check low-voltage transformer leads R (red) and C(brown). Be sure they are wired to correct locations.

2. Check output voltage of transformer secondary side R (red)and C (brown). Be sure transformer output is between 18and 30 vac. If transformer output is incorrect and trans-former is receiving correct input voltage (208v or 230v),then transformer needs to be replaced with recommendedtransformer. If no problem exists with transformer second-ary, proceed to items 3 and 4.

3. Check low-voltage fuse shown in Fig. 3A. If fuse is blown,replace it with an identical 5-amp fuse. The transformercannot supply power to board with fuse blown or loose. Iffuse blows when unit has power applied to it, the systemmost likely has 1 of the following problems:

a. Check all 24-v wiring for an electrical short.

b. The maximum load on transformer is 40 VA. If load ontransformer is excessive, the low-voltage 5-amp fusewill blow to protect transformer. If load exceeds VArating of transformer, a larger VA rated transformerneeds to be installed. Check sequencers/relays for exces-sive current draw.

c. Check wiring of heaters. If a heater is miswired, fusemay blow. If a heater is miswired, correct miswiring bycomparing it to heater wiring label.

4. Check connections on primary side of transformer. If theyare not connected properly, the transformer secondary

cannot supply the 24-v signal to energize fan relay. Iftransformer is receiving correct primary voltage but is notputting out correct secondary voltage, transformer needs tobe replaced.

B. If Electric Heat Stages Will Not Turn On But Fan WillTurn On:

IF THERE IS NO HIGH VOLTAGE TO TRANSFORMER:

1. Check plug connection between heaters and board. Thissupplies power to transformer and fan. Be sure plug isconnected properly.

2. Check sequencer/relay number 1 and plug wiring. Yellowwire should be connected to pin number 9 of plug and tolimit switch. Black wire should be connected to pin number7 of plug and to sequencer/relay number 1.

3. Check incoming high-voltage power leads. If these are notreceiving power, system cannot function.

IF TRANSFORMER HAS HIGH VOLTAGE APPLIED TO IT:

1. Check low-voltage transformer leads R (red) and C(brown). Make sure they are wired to correct location. Theunit will not function without proper connections.

2. Check output voltage of transformer secondary side R (red)and C (brown). If transformer output is low (less than 18vac), refer to items 3 and 4 of previous "If Transformer HasHigh Voltage Applied To It" section.

IF TRACES ARE OVERHEATED ON BACK OF PCB:

Usually whenever a trace is blown on PCB, it means either therehas been a high-voltage short or high voltage has been applied tolow-voltage circuit. This can be prevented by making sure PCB iswired correctly before PCB has power applied to it.

C. If Transformer Fuse Keeps Blowing:

When low-voltage fuse blows, it means transformer would haveblown if fuse had not been in circuit to protect it. The fuse usuallyblows when there is a high current draw on transformer, high

Fig. 3C—Electric Heater Control BoxesA98184

3127

53T-

O-D

60T

X11

HH

19Z

A94

5

C97

25L1

45-5

5F

3127

53T-

O-D

60T

X11

HH

19Z

A94

5

C97

25L1

45-5

5F

SPT

FANRELAY

NO

NC

5 PULL TO OPEN

WARNING

ELECTRIC SHOCKHAZARD

DISCONNECTREMOTE POWERSUPPLY BEFOREOPENING PANEL.

322861-101 REV. A

PULL TO OPEN

WARNING

ELECTRIC SHOCKHAZARD

DISCONNECTREMOTE POWERSUPPLY BEFOREOPENING PANEL.

322861-101 REV. A

3127

53T-

O-D

60T

X11

HH

19Z

A94

5

C97

01L1

45-5

5F

3127

53T-

O-D

60T

X11

HH

19Z

A94

5

C97

01L1

45-5

5F

FF1D CONTROL BOX

FF1A/FF1B/FF1C CONTROL BOX

—6—

voltage applied to low-voltage circuit, or a direct secondary short.When there is a high current draw on transformer, it is most likelybecause transformer has been shorted or system is trying to drawmore VA than transformer rating allows. When fuse blows becauseof high voltage, the system has mixed high- and low-voltagesignals.

1. Check wiring of sequencers/relays as shown in Fig. 4 and 5.Be sure transformer is not shorting out because thermostatwires are miswired.

2. Check wiring of sequencers/relays as shown in Fig. 4 and 5.Be sure low-voltage and high-voltage wiring is correct.

3. Check VA draw on transformer. If VA draw is more thanVA rating of transformer, fuse will blow. If this is the case,replace transformer with one that has a higher VA ratingand meets system specifications.

D. If Fan Runs Continuously:

1. If PCB has no low-voltage power, check blue and black fanleads. These may be switched at sequencer/relay.

2. If PCB has low-voltage power, check fan relay to see if it isopening and closing. It may be stuck in the normally-closedposition due to debris in relay.

Fig. 4—Wiring Diagram of Sequencer HeaterA94346

1. USE COPPER WIRE (75°C MIN) ONLY BETWEEN DISCONNECT SWITCH AND UNIT.2. TO BE WIRED IN ACCORDANCE WITH NEC AND LOCAL CODES.3. TRANSFORMER PRIMARY LEADS, BLUE 208V, RED 230V.4. IF ANY OF THE ORIGINAL WIRE, AS SUPPLIED, MUST BE REPLACED,

USE THE SAME OR EQUIVALENT TYPE WIRE.5. REPLACE LOW VOLTAGE FUSE WITH NO GREATER THAN 5 AMP FUSE.6. 20KW HEATER USES ONE DOUBLE POLE LS ON MIDDLE TOP ELEMENT.7. 18, 24 AND 30KW HEATERS USE DOUBLE POLE LIMIT SWITCHES.8. LARGEST HEATERS ARE SHOWN, SMALLER HEATERS WILL HAVE FEWER ELEMENTS AND

COMPONENTS.9. 1 PHASE HEATERS ARE SHOWN WIRED FOR SINGLE SUPPLY CIRCUIT.10. USE 60 AMP CLASS K FUSES ONLY, FOR REPLACEMENT.11. (3) SPEED MOTOR SHOWN. OPTIONAL (2) SPEED MOTOR USES HI (BLK) AND LOW

(BLU OR RED).12. CONNECT R TO R, G TO G, ETC., SEE OUTDOOR INSTRUCTION FOR DETAILS.13. IF WIRE CRIMP IS REMOVED AN EMERGENCY HEAT RELAY IS REQUIRED.

(SEE OUTDOOR-THERMOSTAT INSTRUCTIONS)

THIS COMPARTMENT MUST BE CLOSED EXCEPT FOR SERVICING CAUTION:

ATTENTION:

NOT SUITABLE FOR USE ON SYSTEMS EXCEEDING150V TO GROUNDBLOWER MOTOR

ROTATION

CAPCOMFFM

FRFUGNDHVTBHTR

CAPACITORCOMMONLOW VOLTAGE FUSEFAN MOTORFIELD POWER WIRINGPCB FAN RELAYLINE FUSEEQUIPMENT GROUNDHIGH VOLTAGE TERM BLOCKHEATER

LS

PCBSEQTRAN

RECPCB

LEGEND

321214-101 REV. C

30KW 1PH SCHEMATIC DIAGRAM

FIELD POWER WIRING DISCONNECT PER NEC

SEE RATING PLATEFOR VOLTS & HERTZ

GND

HTR6 BLK12

LS6

YEL

FU6BLK

FU5 11YEL BLK

L2L1

HTR5 BLK10

LS59

SEQ 3BLK

HTR4 BLK8YEL LS4

YEL

BLK7YEL

BLK

HTR3 BLK6

LS35

SEQ 2

BLK

HTR2 BLK4

YEL

LS2YEL BLK3

YEL

BLK

HTR1 BLK2

LS11

SEQ 1

BLK

LIMIT SWITCHMARKED TERMINALPLUG AND RECEPTACLEPRINTED CIRCUIT BOARDSEQUENCERTRANSFORMERUNMARKED TERMINALRECEPTACLECIRCUIT BREAKER

BLKBLU

YEL

YEL

SEE NOTE #1

NOTES:

799

11 711 3 2 6 1

23 1644

GRY

OUTDOORUNIT

WHT

GR

Y

G

RED

BRN EW3W2

W2C

BRN

INDOORTHERMOSTAT

RE

D

WH

T

VIO

BR

N

RECP

PLUG

F1

SPT G

PCB BLK

CT

RFR

BLU BLK

230V208VYEL

BRNYEL

YEL

YEL-COM

CA

P

BRN

FMBRN

GRN/YEL-GND

BLK-HI

BLU-MEDRED-LO

BRN

REDTRAN

CO

M

RED

GRAYVIOORN

BRN

BLU BLK

SEQ1SEQ3

SEQ2

CB/FU3

CB/FU1

CB/FU4

CB/FU2

HVTB

NO

NC

9 11 7 23 16 4208/240VAC 24VAC 24VAC

PLUG

23 16 49 11 7

L1 L2

FIELD POWER WIRING

FIELDPOWERWIRING

BLKYEL

HTR6 BLK12

LS6

YEL

FU6FU5 11

YEL

BLK

HTR5 BLK10

LS59

SEQ 3BLK

HTR4 BLK8

YEL LS4

YEL

7BLK

HTR3 BLK6

LS35

SEQ 2

BLK

HTR2 BLK4

YEL

LS2YEL3

BLK

HTR1 BLK2

LS11

SEQ 1

BLK

YEL

YEL

CB/FU3

CB/FU1

CB/FU4

CB/FU2

FIELD POWER WIRING DISCONNECT PER NECSEE RATING PLATE FOR VOLTS & HERTZ

GND

BLKL2L1

SEE NOTE #1

HVTB

L3

VIOORNSEQ1

9 11 7 23

RED

PLUG

BRNGRAY

BRN

SEQ3

SEQ2

16 4208/240VAC 24VAC 24VAC


RESP

YEL

BLK

BLK

COOLING CONTROL ONLY

SEE NOTE #13R

BARRIER SEE NOTE #12

BLU

—7—

E. Transformer Failure:

1. Check 208-v and 230-v transformer connections. They maybe miswired.

CIRCUIT BOARD FUNCTION AND TROUBLESHOOTINGHK61GA001 and HK61GA003 Circuit BoardsThis section of the service manual describes the HK61GA001 andHK61GA003 printed-circuit boards (PCB) by examining thefunctional operation of the printed-circuit board’s components.I. PCB COMPONENT LAYOUT AND DESCRIPTION

Layout of the actual printed-circuit boards are depicted inFig. 6 and Fig. 7.

1. The low-voltage terminal board is used to connect theindoor thermostat to the low, 24-v side of the transformer,and to serve as a junction between the indoor thermostat andthe outdoor section.

2. Break off the tabs.a. W2-3 — Used to control (stage) the second stage of

electric heat. The first stage controlling electric heat andthe indoor fan are interlocked through diodes.

b. W2-E — Used to control (stage) the third stage ofelectric heat.

3. A fuse is used to protect the low-voltage transformer.4. AUX 1 and AUX 2 are connections for the latent capacity

control, delay off kit, 2-speed kit and air conditioningaccessories.

5. F1, F2, F3, and F4 are connections for the indoor fan.6. EAC1 and EAC2 are 240-v connections, which parallel fan

lead connections, for the electronic air cleaner.7. L1 and L2 are 240-v connections which parallel power

input.

→ Fig. 5—Wiring Diagram of Relay HeaterA99121E

COMPONENT ARRANGEMENT

HTR1 HTR3 HTR2

COM

208 V230 V

TRANRED

24 V

BRN

SYSTEM TRANSFORMER: 40.0VAFAN COIL/HEATER: 11.8VA

REMAINING VA AVAILABLE: 28.2VA

LEGEND

1.Use copper wire (75 ̊C min.) only between disconnect switch and unit.2.To be wired in accordance with N.E.C. and local codes.3. If any of the original wire, as supplied, must be replaced, use the same or

equivalent type wire.4.Replace low voltage fuse with no greater than 5 amp fuse.5.Use 60 amp class K fuses only, for replacement.6.(3) speed motor shown. Optional (2) speed motor uses HI (BLK) and LOW

(BLU or RED).7.Connect R to R, G to G, etc., see outdoor instruction for details.8.Smaller heaters will have fewer components.

SEE NOTE #6

GND

RED-LOWBLU-MEDBLK-HI

GRN/YEL-GND

FM BRNBRNYEL-COM

FAN MOTOR THERMALLY PROTECTED

CAPGND

324984-101 REV. A

FIELD POWER WIRING DISCONNECT PER NECSEE RATING PLATEFOR VOLTS & HERTZ

GND L4 L2L1 L3

HTR4 BLK 4YEL LS4

YEL

2 BLK

HTR3 BLK 8LS3 6RELAY 2

BLK

HTR2 BLK

4

YEL

LS2

YEL

2

YEL

BLK

HTR1 BLK

4

LS12

RELAY 1

BLK

YEL

HTR

4

FU4

FU2

L2

CB1

L4

CB2

FU1

FU3

L3

CB1

L1

CB2

LS1 LS2

INTERNAL PROTECTION MAY BE EITHER FUSES OR CIRCUIT BREAKERS

L4 L3CB1

60A 60A

L2 L1CB2

60A 60A

NOTES:

MINIMUM MOTOR SPEED SELECTIONFAN COIL SIZE

LO LOMOTOR SPEED AT 20 KW -- MED LO LO

018 024 030 036 042 048 060 070

-- LO

PLUG44

6 116

RECP

VIO

BLU

99

BARRIER

YEL

BRN

WG

GR

Y

OUTDOORUNIT

SEE NOTE #8

SEE NOTE #1

NCNO

SPTFR

TC

1RG

PCB

F

THIS COMPARTMENT MUST BE CLOSED EXCEPT FOR SERVICING CAUTION:

ATTENTION:

NOT SUITABLE FOR USE ON SYSTEMS EXCEEDING 150V TO GROUND

NE CONVIENT PAS AUX INSTALLATIONS DE PLUS DE 150 V A LA TERRE

BLOWER MOTORROTATION

SCHEMATIC DIAGRAM

F1

SPT GRY

BLU BLK

WHT

REDG

PCB BLKBRN

RC

INDOOR THERMOSTAT

RED

WH

T

BRNC

T

RFR

711 711 3 2

23

VIOORNBLU BLK

NCNO

LS 3& 4

230V208V

BRN

REDTRAN

COM

GRNYELGND

YEL

LOMED

HI

COM

REDBLU

YELBLK

FM

BRN BRN

CAP

BLK

R E C

RELAY 122 VDC COIL

TDR

HEATERLIMIT SWITCHMARKED TERMINALPLUG AND RECEPTACLEPRINTED CIRCUIT BOARDRECTIFIERTRANSFORMERUNMARKED TERMINALTIME DELAYRECTIFIER

CIRCUIT BREAKERCAPACITORCOMMONLOW VOLTAGE FUSEFAN MOTORFIELD POWER WIRINGPCB FAN RELAYLINE FUSEEQUIPMENT GROUNDFAN SPEED TAP LOCATION

REC

HTRLS

PCB

TRAN

CBCAPCOM

FFM

FRFU

GNDSPT

BLU

W2

RELAY 3

RELAY 2

RELAY 322 VDC COIL

R E C

RELAY 222 VDC COIL

T D R

BRN

BRN

GRY

RED

R1 R2

R3

FU3FU1

FU4FU2

L3L1

L4L2

RELAY 1

RELAY 2

REC

TDRRELAY 3

8

6

4

2

1 0

8

6

4

2

1 0

8

6

4

2

1 0TDR

—8—

8. T1, T2 and T3 are connections for the primary, high-voltageside of the transformer.

9. The fan relay is controlled by the thermostat and turns thefan on and off.

10. A plug is used as the connection for the PCB power andelectric heaters. Note the pin numbers on the plug.

11. Diodes provide DC power for the fan relay and the firststage of electric heat: W2, W3 or E.

II. PCB COMPONENT FUNCTIONS

A. Low-Voltage Terminal Board

The low-voltage terminal board connects the indoor thermostat tothe outdoor unit as shown in Fig. 8. The terminals are listed asfollows along with their functional control.

1. R is used to connect the secondary side of the transformer.The red wire provides low voltage (24v) to the PCB and thethermostat. R is fused on the HK61GA003 board.

Fig. 6—HK61GA001 Printed-Circuit BoardA97025

2FC-1

AUX1

AUX2

DUMMY

DUMMY

DUMMY

COMMON

COMMON

240 VAC 240 VAC

TRANSFORMERAC LINE

FANRELAY

24VDC

FANEAC2L2T3T2T1

EAC1L1

F4

F3

F2

F1

123

456

789

101112

C

HK61GA001A

W2-

3W

2-E

5 A

MP

F

US

E

MA

XFA

N

TD

B

LOW VOLTAGETERMINAL BOARD

2ND STAGE

3RD STAGE

NOT USED

FUSE(LOW VOLTAGE)

CONNECTIONSFOR VARIOUSACCESSORIES

FAN CONNECTIONS

ELECTRONIC AIRCLEANER CONNECTIONS

ELECTRIC HEATBREAKOFF TABSFOR STAGING

HK61GA001

PLUG

INTERLOCKDIODES

TRANSFORMERCONNECTIONS

—9—

2. C is used to connect the brown wire of the thermostat toprovide a return path to ground through the fuse whichprotects the transformer. C is fused on the HK61GA001board.

3. G is used to control the switching of the relay to turn the fanon through the normally open contact of the relay.

4. Y on the HK61GA001 is used as the junction for theoutdoor section’s Y connection which controls the compres-

sor contactor for heat pump and cooling modes. TheHK61GA003 board contains a 90-sec fan-off delay whichbegins timing when the Y is de-energized.

5. O is used as a junction for a heat pump reversing valvecircuit.

Fig. 7—HK61GA003 Printed-Circuit BoardA97026

36912

25811

14710


2ND STAGE

3RD STAGE

FUSE(LOW VOLTAGE)

CONNECTIONSFOR VARIOUSACCESSORIES

FAN CONNECTIONS

ELECTRIC HEATBREAKOFF TABSFOR STAGING

HK61GA003

PLUG

TRANSFORMERCONNECTIONS

ELECTRONIC AIRCLEANER CONNECTIONS

FAN INTERLOCKDIODES AND FANTIME DELAY OFF

CIRCUIT

AUX1

W3

L

W2

O

E

Y

G

R

C

AUX2

DUMMY

DUMMY

DUMMY

COMMON

COMMON

240 VAC 240 VACTRANSFORMER

AC LINE

FANRELAY

24VDC

FANEAC2L2T3T2T1

EAC1L1

F4

F3

F2

F1

HK61GA003

Y

R

W2-

3

5 A

MP

F

US

E

MA

X2F

D-1

W2-

E

—10—

6. W2 is used to turn on the first stage of electric heat whichis interlocked with the fan through the normally closed fanrelay. Unless the tabs are broken off, all stages of electricheat will turn on when W2 receives a signal from thethermostat.

7. W3 is used to turn on the second stage of electric heat. Notethe W2 and W3 tab must be broken off for individualstaging to take place. Energizing W3 will always turn on thefirst stage through the diodes even if the tabs are broken off.

8. E is used to turn on the third stage of electric heat. Note thatthe W3 and E tab must be broken for this individual staging.Energizing E will always turn on the first stage through thediodes even if the tab is broken off.

9. L is used as a junction to wire a diagnostic light (LED) onselected thermostats.

B. Transformer

The proper wiring of the transformer on the HK61GA001 board isillustrated in Fig. 8. Note that T1, T2, and T3 are wired to theprimary or high side of the transformer. The blue wire is connectedto T3 for 208-v applications. The red wire is connected to T3 for230-v applications. Units are factory wired at 230v. The T2terminal is a dummy.

C. Indoor Fan

1. Wiring--The fan connects to F1, F2, F3, and F4 as shown inFig. 8. Note that F2 and F3 are dummy terminals. Thedesired fan speed is connected to F4 and the common isconnected to F1. Units are factory wired at medium speed.

2. Functional Controla. Thermostat and Relay Control--When the thermostat

calls for the fan in cooling, heat pump, electric heat, orfan-only mode, a24-v dcsignal is sent to the relay. Thiscauses the relay to close its normally open contacts, thusturning on the fan. When the thermostat no longer callsfor the fan, the signal sent to the relay is turned off andthe relay opens causing the fan to turn off. TheHK61GA003 board contains a 90-sec fan-off delay whenY is de-energized.

b. Sequencer Interlock--The fan will also turn on wheneverthere is any call for electric heat, even if the fan relay isnot energized. This happens because the fan is inter-locked with the first stage of electric heat through thenormally closed contact of the fan relay.

D. Electric Heat

When the thermostat calls for electric heat, a 24-v signal is sent tothe PCB through W2, causing the first stage to turn on. W3 and Ealso receive the signal if the tabs are not broken off the PCB. Thesignal sent to W2 causes the first stage to turn on. If the tabs arebroken off the PCB, the sequencers can be controlled individuallyto stage the electric heat. The sequence control is described in thefollowing section:

1. W2--When the thermostat sends a signal to W2, a 24-v dcsignal is applied across sequencer number 1, causing it toclose. When sequencer number 1 closes, the first stage ofelectric heat energizes after a short delay. In straight electricheat, the fan is also energized through the normally closedcontacts of the fan relay. In cooling, heat pump, or manualfan mode, the fan will already be running since the fan relaywould have been energized. When the thermostat stopscalling for electric heat, the 24-v dc signal to sequencernumber 1 turns off and the sequencer opens after a delay of60 to 90 sec. When the sequencer opens, the first stage ofheat turns off along with the fan, providing that thethermostat is not calling for the fan. Note that the electricheat cannot be turned on without the fan being turned on atthe same time. This is a fan interlock system.

2. W3--When a signal is sent to W3, 2 control signals are sentout to the sequencers; a 24-v dc signal to sequencer number1 through the diode interlock, and a 24-v ac signal tosequencer number 2. The 24-v ac signal applied to sequencenumber 2 causes the sequencer to close, with the secondstage of electric heat turning on after a short delay.

The 24-v dc signal applied to sequencer number 1 causes the firststage of electric heat to turn on in the same manner as described inW2 above. Note that W3 is interlocked with the fan, sincesequencer number 1 is turned on whenever W3 has a signal sent toit. Timing is such that sequencer number 1 will turn on beforesequencer number 2. When the signal to W3 is turned off,sequencer number 2 opens after a short delay. If W2 is alsosatisfied, the first stage of electric heat and the fan will also turnoff, providing the thermostat is not calling for the fan to be on.E--When the thermostat sends a signal to E 2 signals are sent outto the sequencers. A 24-v ac signal is sent to sequencer number 3and a 24-v dc signal is sent to sequencer number 1. The 24-v acsignal applied to sequencer number 3 turns on the third stage ofelectric heat. The 24-v dc signal applied to sequencer 1 turns on thefirst stage of electric heat and the fan in the same manner as W3.Note that E is also interlocked with the fan.When the thermostat stops calling for electric heat, the signals tosequencers 1 and 3 are turned off and the sequencers open. Thiscauses the electric heat to turn off with the fan if the thermostat isnot calling for the fan.E. Accessories

1. EAC1 and EAC2 for Electronic Air Cleanersa. There are 240-v electronic air cleaner contacts provided

at EAC1 and EAC2. The electronic air cleaner isconnected in parallel with the fan so that it is onwhenever the fan is on. A 120-v installation is similar infunction but connected between EAC2 and neutral of230-v: 120-v transformer connected to EAC1 and EAC2.Refer to electronic air cleaner literature for furtherinformation.

2. AUX1 and AUX2 for 2-Speed Fan Relay Kita. Use to control fan speed operation, high speed for

cooling, heat pump, and fan-only modes. Low speed isused for electric heat. Fig. 9 shows proper connection for24-v dc 2-speed fan relay kit. Note that kit’s relay coil isin parallel with fan relay coil on PCB connected toAUX1 and AUX2. Make sure the normally closedcontact is connected to the lower speed.

b. The latent capacity control kit is used to control fanspeed operation when the relative humidity is above a setpoint on humidistat. Humidistat opens and 2-speed fanrelay remains in normally closed position with fan motorrunning at a lower speed for maximum humidity control.Fig. 10 shows proper connection for latent capacitycontrol kit. Note that it is connected in the same manneras 2-speed fan relay kit but with relay connected tohumidistat (orange wires).

c. Time delay-off relay kit is used to increase the efficiencyof the system by delaying the fan from turning off afterthe thermostat is satisfied on the HK61GA001 board.The HK61GA003 board has this feature as standard. Theproper wiring and mounting of the time delay-off relaykit is shown in Fig. 11.

d. Latent capacity control and time delay-off connectionsare shown in Fig. 12, for the HK61GA001 board only.

III. TROUBLESHOOTING THE PRINTED-CIRCUITBOARD

Use Fig. 13 wiring schematic as a guide in troubleshooting thePCB unless otherwise noted.

—11—

Fig. 8—10kw to 20kw CircuitsA97027

2FC-1

W3

L

W2

O

E

Y

G

R

C

AUX1

AUX2

DUMMY

DUMMY

DUMMY

COMMON

COMMON

240 VAC 240 VAC

TRANSFORMERAC LINE

RELAY

24VDC

FANEAC2L2T3T2T1

EAC1L1

F4

F3

F2

F1

123

456

789

101112

C

HK61GA001A

TOINDOOR

THERMOSTAT

W2-

3W

2-E

5 A

MP

F

US

E

MA

XFA

N

TD

B

YEL LS 5 HTR5 BLK BLK10 9

YELFU5 FU6

SEQ 3

LS 6 HTR6 BLK BLK12 11


YELFU3 FU4

SEQ 2


YEL LS 1 HTR1 BLK BLK

BLU-MED

BLU-MED

RED-LO

RED-LO

BRN

BRNCAP

2 1

YELFU1 FU2

SEQ 1


SEQ1

GRAY

YEL

BLU

BLK

GRAY

BRNBRN

BLK

BLKCOMM

TRAN BRN (24V)

RED (24V)

BLU

YEL

VIO

ORG

REDSEQ2SEQ3

BLK-HI

BLK-HI

GRN/YEL-GND

YEL-COM

FM

BLU(208V) RED

(230V)


CONNECT E TO EC TO C ETC.

—12—

Fig

.9—

Tw

o-S

peed

Fan

Rel

ayK

itA

9702

8

W3

W2

EG

CC

B

2-05

868-

2A

TW

O S

PE

ED

FA

N

RE

LAY

WIR

ING

LOW

VO

LTA

GE

BO

AR

D

L

FR

CB

FA

N R

ELA

YC

IRC

UIT

BO

AR

D

MA

RK

ED

TE

RM

INA

LU

NM

AR

KE

D T

ER

MIN

AL

FIE

LD C

TR

L W

IRIN

GF

AC

TO

RY

PO

WE

R W

IRIN

GF

IELD

PO

WE

R W

IRIN

G

AU

X

1A

UX

2

F4

24 V

DC

OR

G

RE

D

FR

LOW

MT

R S

PD

HI M

TR

SP

DF

AN

CO

MM

ON

UN

US

ED

LE

AD

BLK

208/

240

VA

C

CO

M

NO

NC

F3

F2

L2

F1

OY

RTRA

NSFORM

ER ACLINE

T1T2

COMMON

COMMON

DUMMYT3L2

L1F1

F2

F3

F4

2SD-1

C

AUX1

AUX2 VA

C

EAC2

FANEAC

1

LO

YR

CG

EW

2W

3

AU

X 1

AU

X 2

OR

G

RE

D

BLK

YE

L

NO

TO

�H

IGH

ER

F

AN

SP

EE

D

LOW

-VO

LTA

GE

C

OIL

TE

RM

INA

LS

NC

TO

�LO

WE

R

FA

N S

PE

ED

DU

MM

Y T

ER

MIN

ALS

FO

R

UN

US

ED

FA

N M

OT

OR

S

PE

ED

-TA

P

LEA

DS

FA

N M

OT

OR

C

OM

MO

N L

EA

D

—13—

Fig

.10

—La

tent

Cap

acity

Con

trol

Kit

A97

029

VAC

W3

W2

EG

CC

B

2-05

868-

1A

LAT

EN

T C

AP

AC

ITY

C

ON

TR

OL

WIR

ING

LOW

VO

LTA

GE

BO

AR

D

L

FR

CB

FA

N R

ELA

YC

IRC

UIT

BO

AR

DH

ST

HU

MID

IST

AT

MA

RK

ED

TE

RM

INA

LU

NM

AR

KE

D T

ER

MIN

AL

FIE

LD C

TR

L W

IRIN

GF

AC

TO

RY

PO

WE

R W

IRIN

GF

IELD

PO

WE

R W

IRIN

G

AU

X

1A

UX

2

F4

24 V

DC

RE

D

FR

LOW

MT

R S

PD

HI M

TR

SP

DF

AN

CO

MM

ON

UN

US

ED

LE

AD

BLK

208/

240

VA

C

NO C

HS

T

OR

G

OR

G

CO

M

NO

NC

F3

F2

L2

F1

OY

R

TRANSF

ORMER AC

LINET1

T2COM

MON

COMMON

DUMMYT3L2

L1F1

F2

F3

F4

2SD-1

C

AUX1

AUX2

EAC2

FANEAC

1

LO

YR

CG

EW

2W

3

AU

X 1

AU

X 2

RE

D

BLK

YE

L

NO

TO

�H

IGH

ER

F

AN

SP

EE

DO

RA

NG

E W

IRE

S

TO

HU

MID

IST

AT

NC

TO

�LO

WE

R

FA

N S

PE

ED

FA

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OT

OR

C

OM

MO

N L

EA

D

—14—

Fig

.11

—T

ime

Del

ay-O

ffR

elay

Kit

A97

030

W3

W2

EG

CC

B

1

23

2-05

868-

3A

TIM

E D

ELA

Y

RE

LAY

WIR

ING

LOW

VO

LTA

GE

BO

AR

D

L

FR

CB

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YC

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UIT

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LU

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AR

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RY

PO

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IRIN

GF

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PO

WE

R W

IRIN

G

AU

X

1A

UX

2

F4

24 V

DC

TD

RY

EL

FA

N C

OM

MO

NU

NU

SE

D L

EA

DU

NU

SE

D L

EA

D

BLK

208/

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VA

C

CO

M

NO

NC

F3

F2

L2

F1

OY

R

TRANSF

ORMER AC

LINET1

T2COM

MON

COMMON

DUMMYT3L2

L1F1

F2

F3

F4

2FC-1

HK61GA

001

G

C

C

AUX1

AUX2

EAC2

FANEAC

1

LO

YR

CG

EW

2W

3

TO

FA

N M

TR

S

PE

ED

TA

PV

IOB

RN

YE

L

YE

L

BLK

BR

N

VIO

FA

N

MO

TO

R

CO

MM

ON

LE

AD

FA

N

MO

TO

R

SP

EE

D-T

AP

LE

AD

—15—

Fig

.12

—La

tent

Cap

acity

Con

trol

and

Tim

eD

elay

-Off

Rel

ayK

itsA

9703

1

W3

W2

EG

CC

B

1

23

2-05

868-

4A

TIM

E D

ELA

Y R

ELA

Y

TW

O S

PE

ED

FA

N R

ELA

Y

(LA

TE

NT

CA

PA

CIT

Y)

LOW

VO

LTA

GE

BO

AR

D

L

FR

CB

FA

N R

ELA

YC

IRC

UIT

BO

AR

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ST

HU

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ST

AT

TD

RT

IME

DE

LAY

RE

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MA

RK

ED

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RM

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LU

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AR

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FIE

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GF

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TO

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R W

IRIN

GF

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PO

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R W

IRIN

G

AU

X

1A

UX

2

F4

24 V

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RF

R OR

G

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ED

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L

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NU

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EA

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208/

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M

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F3

F2

L2

F1

OY

R

CO

M

NO

NC

TRANSF

ORMER AC

LINET1

T2COM

MON

COMMON

DUMMYT3L2

L1F1

F2

F3

F4

2SD-1

G

C

VAC

EAC2

FANEAC

1

LO

YR

CG

EW

2W

3

VIO

BR

N

YE

L

VIO

FA

N

MO

TO

R

CO

MM

ON

LE

AD

RE

DO

RG

BLK

BR

N

YE

L

AU

X 2

AU

X 1

OR

G

OR

G

BLU

LOW

-VO

LTA

GE

C

OIL

TE

RM

INA

LS

TO

HU

MID

IST

AT

(O

PT

ION

AL,

SH

OW

N

WIT

H D

AS

HE

D L

INE

S)

NO

TO

�H

IGH

ER

F

AN

SP

EE

D

NC

TO

�LO

WE

R

FA

N S

PE

ED

NO C

HS

T

—16—

Fig. 13—Wiring SchematicA97032

DUMMY

DUMMY

F4

F3

F2

F1

DUMMY

240 VAC 240 VAC COMMON

240 VDC

COMMON

T2

AC LINE

T1

123

W3

W2

E

L

O

Y

C

R

G

456

789

1011

PLUG

RELAY

12

T3L2 EAC2

AUX1

C 5 AMPFUSEMAX

AUX2

L1 EAC1

FAN

RL

GE

CO

YW

2

IND

OO

R T

HE

RM

OS

TA

T

YELYEL BLK


YELFU1 FU2FU3 FU4

SEQ 2



YEL

SEQ 1


SEQ1

SEQ2

BLU

BLK

YEL

YEL

BLU

BLK

BRN

RED

VIO

ORG

TERM BOARD

BLU-MED

RED-LO

BRN

BRNCAP

BLK-HI

GRN/YEL-GND

YEL-COMMON

RED(230V)

BLU(208V)

RED(24V)

BLKCOMM

BRNCOMM

TRAN

FM

C

CR

ON TERMINAL BOARD ABOVE

—17—

A. If the fan will not turn on from the thermostat:

IF THERE IS NO HIGH VOLTAGE TO THE PCB:

1. Check the plug/receptacle connection; this brings power tothe PCB. Make sure the plug is connected properly.

2. Check sequencer number 1 and the plug’s wiring; theyellow wire should be connected to pin number 9 of theplug and the limit switch. A black wire should be connectedto pin number 7 of the plug and to sequencer number 1.

3. Check power leads L1 and L2. If these are not receivingpower, the system cannot function.

IF THE PCB HAS HIGH VOLTAGE APPLIED TO IT:

1. Check the low-voltage transformer leads, R and C. Makesure they are wired to the correct locations. Note thatFig. 13 shows wiring of the HK61GA001 board.

2. Check the output voltage of the secondary side, R and C, ofthe transformer. If the circuit board is a HK61GA003, makesure the ground strap is in place from C to the bracket. Thisstrap must be in place to complete the 24-v circuit. Makesure the transformer output is around 24-v ac. If thetransformer output is zero-v ac and the transformer isreceiving the correct input voltage (208-v or 240-v), thenthe transformer needs to be replaced with the recommendedtransformer. If the transformer output is 24-v ac, thenproceed to 3 and 4.

3. Check the low-voltage fuse shown in Fig. 6 and Fig. 7. Ifthe fuse is blown, replace it. The transformer cannot supplypower to the board with the fuse blown or loose. If the fuseblows when the unit has power applied to it, the systemmost likely has 1 of the following problems:a. If the transformer is shorting out, check the wiring of the

transformer.

b. The maximum load on the transformer is 40 VA. If theload on the transformer is excessive, the low-voltage,5-amp fuse will blow to protect the transformer. If theload exceeds the VA rating of the transformer, a largerVA rated transformer needs to be installed. Check thesequencers for excessive current draw.

c. Check the wiring of the heaters. If the heater is miswired,the fuse may blow. Check the diodes shown in Fig. 14for signs of overheating. If the heater is miswired,correct the miswiring.

4. Check the T1, T2, and T3 connections on the primary sideof the transformer. If they are not connected properly, thelow-voltage terminal board cannot supply the 24-v signal toenergize the fan relay. If the transformer is receiving thecorrect primary voltage but is not outputting the correctsecondary voltage, the transformer needs to be replaced.

B. If the electric heat stages will not turn on but the fanwill turn on:

1. Check the wiring of the sequencer. Pay particular attentionto the high and low-voltage wiring of the sequencers.

2. Check the plug wiring to make sure that it is wiredcorrectly.

3. Check the voltage to the sequencer; sequencer number 1receives a 24-vac signal. If it is receiving the correctvoltage, check to see if the sequencer is closing. If thesequencer is not closing but is receiving the correct voltage,replace the sequencer. If the sequencer is closing, check thehigh-voltage wiring as discussed in 1 and 2.

C. If the electric heat and the fan will not turn on:

IF THERE IS NO HIGH VOLTAGE TO THE PCB:

1. Check the plug connection. This brings power to the PCBtransformer and the fan. Make sure the plug is connectedproperly.

2. Check sequencer number 1 and the plug wiring. The yellowwire should be connected to pin number 9 of the plug andthe limit switch. The black wire should be connected to pinnumber 7 of the plug and to sequencer number 1.

3. Check incoming high-voltage power leads. If these are notreceiving power, the system cannot function.

IF THE PCB HAS HIGH-VOLTAGE APPLIED TO IT:

1. Check the low-voltage transformer leads, R and C. Makesure they are wired to the correct location. The unit will notfunction without proper connections.

2. Check the output voltage of the secondary side, R and C, ofthe transformer. If the circuit board is an HK61GA003,make sure the ground strap is in place from C to the bracket.This strap must be in place to complete the 24-v circuit. Ifthe transformer output is zero-v ac, refer to "If the PCB hashigh voltage applied to it" in column 1, numbers 3 and 4.

D. If the traces are burnt off the back of the PCB:

Usually whenever there is a trace blown on the PCB it meanseither there has been a high-voltage short or high voltage has beenapplied to the low-voltage circuit. This can be prevented bymaking sure the PCB is wired correctly before the PCB has powerapplied to it.

E. If there are blown diodes:

1. If diodes a and b are blown, it is probable the electric heaterplug was miswired. Correct the miswiring. It should benoted the board will need to be replaced if the diodeindicated is bad.

2. If any of the c diodes are blown, the fan is miswired to 1 ofthe low-voltage terminals, AUX1 or AUX2. Check to makesure that the fan leads are connected to the proper terminalsas shown in Fig. 13. If the fan is connected properly, makesure that no other high voltage is applied to the AUXterminals.

F. The PCB fuse keeps blowing:

When the low-voltage fuse blows, it means the transformer wouldhave just blown if the fuse had not been in the circuit to protect it.The fuse usually blows when there is a high current draw on thetransformer, high voltage applied to the low-voltage circuit, or adirect secondary short. When there is a high current draw on thetransformer, it is most likely because the transformer has beenshorted or the system is trying to draw more VA than thetransformer is rated for. When the fuse blows because of highvoltage, the system has mixed high- and low-voltage signals.

1. Check the transformer and thermostat wiring as shown inFig. 11. Make sure the transformer is not shorting out by thethermostat wires being miswired.

2. Check the wiring of the sequencers as shown in Fig. 13.Make sure the low-voltage and the high-voltage wiring areconnected to the proper sequencers.

3. Check the VA draw on the transformer. If the VA draw ismore than the VA rating of the transformer, the fuse willblow. If this is the case, replace the transformer with 1 thathas a higher VA rating and meets system specifications.

G. The fan runs continuously:

1. If the PCB has no low-voltage power, check the blue andblack fan leads. These may be switched at the sequencer.

2. If the PCB has low-voltage power, check the fan relay tosee if it is opening and closing. It may be stuck in thenormally closed position due to debris in the relay.

3. See Service Manager Bulletin (SMB) 92-3.H. Transformer failure:

1. Check the 208-v and 240-v taps connected to T1, and T3.They may be miswired.

—18—

ELECTRIC HEATER FUNCTION ANDTROUBLESHOOTING

This section describes KFA, KFB, KFC, and KFD series electricheaters in exclusion of Smart Heat by examining the functionaloperation of these heaters.

I. DESCRIPTION OF ELECTRIC HEATERCOMPONENTS

A. Limit Switch

The limit switch is a temperature-sensitive control whose functionis to prevent system from overheating in abnormal conditions. Thetemperature settings often vary from heater to heater due tovariations in airflow patterns and element radiant heat conditions.The devices are sized to remain on-line under heat pump condi-tions (115°F air off coil) and minimum CFM, but trip to preventoutlet air conditions above 200°F or excessive component or ducttemperatures.

The device itself consists of a bimetallic disc, which whenoverheated "snaps through" to open a normally-closed high-voltage, high-current switch. When system temperatures coolsufficiently, the switch will automatically reset to its closedposition. Normal failure mode for this switch is open.

If a limit switch has been determined to be defective, NEVERBYPASS THE LIMIT SWITCH. When replacing limit switch,ensure that it is replaced with a limit switch of identical openingtemperature and closing differential. Limits switches are typicallycolor coded to identify their range.

B. KFA and KFB Sequencer

The sequencer is essentially a thermally activated time-delay relaynormally activated by low-voltage control signals from thermostat.The typical sequencer is a 1- or 2-pole normally-open devicewhich energizes within 10 to 30 sec after application of controlsignal and de-energizes 60 to 90 sec after control signal isremoved.

Fig. 14—Control Board Noting DiodesA97033

123

456

789

101112

2FC-1

AUX1

AUX2

DUMMY

DUMMY

DUMMY

COMMON

COMMON

240 VAC 240 VAC

TRANSFORMERAC LINE

RELAY

24VDC

FANEAC2L2T3T2T1

EAC1L1

F4

F3

F2

F1

C

HK61GA001A

W2-

3W

2-E

5 A

MP

F

US

E

MA

XFA

N

TD

B

BLOWNDIODE

(c)

BLOWNDIODE

(a)

BLOWNDIODE

(b)

—19—

In simplistic terms, the sequencers which we use are nothing morethan normally-open limit switches which sit on top of a smallresistive heater. When voltage is applied to this heater, a positivetemperature coefficient resistor (PTC), heat is supplied to abimetallic disc which "snaps through" and closes switch.The time required for PTC to heat to a sufficient point controls ONtiming of device. The time required for disc to cool down whenpower is removed controls OFF time of device. The PTC can bevaried to provide varied timing. Typically a short ON equates to along OFF.Because this is a thermally-activated device, ambient conditionsaffect the ON/OFF cycle. Higher ambient temperature meansshorter ON times and longer OFF times.These sequencers may be "ganged up" to 3 on a common mountingplate to control up to 6 heater elements. In this situation, PTCs aredifferent in each sequencer to provide a staged ON of a minimumof 10 sec between each sequencer — 3 stages of 2 elements sincethe KFA and KFB series heaters use sequencers in which bothswitches of the 2-pole sequencer close simultaneously. Oldermodels used sequencers which had a minimum delay of 10 secbetween each switch.Application of these devices is such that the first switch ON notonly turns on first heater element, but also ensures that indoor fanis energized, because first ON is last OFF. This ensures fanremains ON until the last heater de-energizes.

C. KFC and KFD Electric Heat Relay

KFC and KFD electric heater packages have relays controlling theheater elements instead of sequencers. A small rectifier PCB ismounted to each relay which converts the incoming 24-vac controlsignal to dc. In addition to the rectifier circuit, the second and thirdstage relays contain a time-on delay circuit of 5 seconds for secondstage, and 8 seconds for third stage. When the control signal isremoved from the relays, all relays will open with no time-offdelay.

II. TROUBLESHOOTING KFA, KFB, KFC, AND KFDSERIES ELECTRIC HEATERS

A. Discolored Wire Insulation at Terminal

Check quick-connect terminal at discoloration. Connection may beloose, creating a high resistance through connection point.

B. Fuse Failure

1. Check for shorted wire. Replace wire. Never try to fix wireusing electrical tape.

2. Check shorted element. If element is shorted, replaceheater.

C. No Heat

1. Check fuse for failure. If fuse has failed, refer to FuseFailure section.

2. Check for faulty transformer. Check output voltage oftransformer secondary side R (red) and C (brown). Makesure output is between 18 and 30 vac. If output voltage islow and input voltage tests normal, replace transformer.

3. Check for miswired heater plug harness.

4. Check limit switch or sequencer failure. These switchesshould have failed in open position. If output voltage is zerovolts, replace switch.

5. Check heater relay and PCB (KFC and KFD heaters only).Control voltage input to PCB should be 24-vac. Output torelay should be 18-vdc minimum. If input is present but nooutput, replace PCB. If output is present, replace relay.

D. Heater Will Not Turn Off

1. Check low-voltage wiring for miswire.2. Check for shorted elements to ground.3. Replace sequencer/relays. They may be stuck closed.

E. Nuisance Trips

1. Check for low airflow due to dirty filters, blocked registers,or undersized duct.

2. Check blower motor and wheel for proper operation.Excessive current draw of motor will cause internal over-load to trip.

3. The fan speed may be low.

FAN COIL DESCRIPTIONAND TROUBLESHOOTING

FK4BThe FK4B is similar to the discontinued FK4A as they both haveintegrated controls and motor (ICM) and their own special circuitboard. The greatest difference between the 2 models is the wayeach goes about delivering air.Setting up desired airflow on the FK4B is obtained by theselections made on Easy Select™ circuit board. The motor deliversrequested airflow as defined by signals received from Easy SelectBoard and its internal programming. The major difference is thatthe FK4B motor reacts to changes in system static pressures tomaintain constant airflow.Unlike conventional fan coils where static pressure affects airflow,the FK4B is a constant airflow unit. The blower delivers requestedairflow up to about 0.7 in. of static pressure. The ICM2 ispre-programmed and contains airflows for all modes of operation.Blower characteristics (airflow, torque, and speed-vs-static pres-sure) are known from laboratory testing. If any 3 characteristics areknown, the fourth is defined.Requested airflow is known because of Easy Select board con-figuration and thermostat signals. Torque is known because it isdirectly related to armature current which is measured by motorcontrol. Speed is measured from its generated back EMF. Thisinformation is entered into an expression which calculates torquefrom speed and airflow numbers. If calculation does not matchstored blower characteristics, torque is adjusted every 0.8 sec untilagreement is reached. The unit does not directly measure staticpressure, but does react to a change in static to maintain constantairflow.I. INTEGRATED CONTROLS AND MOTOR (ICM2)

The ICM2 is similar to the ICM1 used in FK4A series units, butcannot be used as a replacement without some modification toFK4A unit. Consult SMB 93-0052 for motor conversion kit. Theelectronics of motor are built into rear of motor, deriving the nameICM. (See Fig. 15.)An ICM is first fed high voltage AC power through the 5-pinconnector. The AC power is then rectified to DC by a diodemodule. After rectification, DC signal is electronically communi-cated and fed in sequential order to 3 stator windings. Thefrequency of communication pulses determines motor speed. Therotor is permanently magnetized.An ICM is powered with high voltage at all times. The motor willnot run with high voltage alone. Low voltage must be applied tocontrol plug to run motor.II. PCB LAYOUT AND DESCRIPTION

NOTE: Layout of actual PCB is depicted in Fig. 16 and 17.The control is a single PCB which interfaces a variable-speedICM2 with other system components.Power for system is supplied from a 230-vac, 60-Hz line. Class 2voltage (24 vac nom.), used for thermostat connections, is derivedfrom a transformer located in close proximity to control. Theprimary and secondary of transformer are connected to controlboard. The 24-vac secondary circuit includes a socket, solderedinto circuit at SEC2, to receive a 5-amp automotive-type fuse.Connection to heater panel is made through 12-circuit connectorP1. Connections to thermostat are made at screw terminals. Linevoltage for ICM2 is made through 7-circuit connector P2. Eighteenquick-connect terminals comprise field select taps for motor.

—20—

Fuse Data: 5-amp automotive-type ATC/ATO (tan)32v200 percent current opening time of 5 sec maximum

A. Electrical Connections

Eighteen 0.187-in quick-connect terminals are used to provideprogramming selections for operating modes of ICM2. The 5selection modes are listed below. For additional information, referto Easy Select Configuration Taps section.

AUX Heat Range—(Violet Wire)AC/HP Size—(Blue Wire)Type—(Orange Wire)AC/HP CFM Adjust—(Black Wire)AC/HP Time Delay—(Grey Wire)

III. SEQUENCE OF OPERATION

A. Continuous Fan Mode

The thermostat closes circuit R to G. The G signal is sent directlyto ICM2.

B. Cooling Mode—Single Speed or 2-Speed High

Thermostat closes circuits R to Y/Y2 and R to O (heat pump only)for single speed. A circuit from R to Y1 is also required for2-speed high. The Y/Y2 signal is sent directly to ICM2.

C. Cooling Mode—Two-Speed Low

Thermostat closes circuits R to Y1 and R to O (heat pump only).The Y1 signal is sent directly to ICM2.

D. Electric Heat Heating Mode

Thermostat closes circuit R to W2, W3, or E.

The terminal block positions W2, W3, and E are tied together byjumpers JW1 and JW2. These jumpers are provided for fieldstaging of electric heater banks through use of thermostats. Whenstaging is a requirement, installer cuts jumpers and wires inthermostats as is the common practice with other fan coils. Toensure motor operation if any 1 of the inputs is energized, the 3electric heater inputs are also interlocked through diodes D1, D2,and D3 to motor W input.

E. Heat Pump Heating Mode—Single Speed or 2-SpeedHigh

Thermostat closes circuit R to Y/Y2 for single speed. A circuitfrom R to Y1 is also required for 2-speed high. The Y/Y2 signalis sent directly to ICM2.

F. Heat Pump Heating Mode—Two-Speed Low

Thermostat closes R to Y1. The Y1 signal is sent directly to ICM2.

G. Heat Pump Heating With Auxiliary Electric Heat

Thermostat closes circuits R to Y/Y2 and/or R to Y1 with R to W2,W3, or E (and R to O in the case of defrost).

See previously described modes for circuit paths.

In the event that electric heating is called for by thermostat whileheat pump is also operating in either heating or defrost mode,

Fig. 15—FK4B, FK4C and FV4A ICM2 MotorA94079

1 2 3 4 5

9

1 2 3 4 5 6 7 8

10 11 12 13 14 15 16

POWER CONNECTOR

CONTROL CONNECTOR

OPTIONAL SAFETY GROUND

OPTIONALSAFETY

GROUND

DO NOT REMOVE

DRAINHOLE

—21—

electric heating signal will appear at motor connector pin 1 asdescribed previously. If necessary, the motor will modify itsairflow output to provide an airflow which is defined as safe foroperation of electric heater.

H. CFM Select Configuration Taps

The CFM Select taps are used by installer to configure system. TheICM2 is capable of discerning wave shapes on some of its inputsand uses this capability to modify its operation to a pre-programmed table of airflows and can be modified in response toother inputs such as the need for de-humidification.

I. ICM2 Control Power

The ICM2 control power is supplied from R circuit throughprinted-circuit runs to motor control connector pin 6, throughmotor control harness to motor. The C side of low-voltage controlpower circuit is connected by printed-circuit runs to motorconnector pins 4 and 5, then through motor control harness tomotor.

J. Low-Voltage Circuit Fusing and Reference

The low-voltage circuit is fused by a board-mounted 5-ampautomotive-type fuse placed in series with transformer SEC2 andR circuit. The C circuit of transformer is referenced to chassisground through a printed-circuit run at SEC1 connected to metalstandoff marked GROUND SCREW REQUIRED.NOTE: A ground screw must be in place or erratic motoroperation can result.K. Transformer, Motor, and Electric HeaterPower Connections

The high-voltage (230-vac) power input to board is providedthrough electric heater connector pins 7 and 9. The high voltage isthen connected through printed-circuit runs to motor power con-

nections M1 and M2 and transformer power connections T1 andT3. Transformer connection T2 is a dummy terminal used forunused primary power lead. The transformer secondary connec-tions are made at SEC1 and SEC2 connectors.

IV. EASY SELECT CONFIGURATION TAPS

The Easy Select taps are used by installer to configure system. TheICM2 uses selected taps to modify its operation to a pre-programmed table of airflows. Airflows are based on system sizeor mode of operation and those airflows are modified in responseto other inputs such as the need for de-humidification.(See Fig. 16.)

The FK4B Fan Coil must be configured to operate properly withsystem components with which it is installed. To successfullyconfigure a basic system (see information printed on circuit boardlocated next to select pins), move the 5 select wires to pins whichmatch components used.

A. Auxiliary Heat Range

The installer must select the auxiliary heat airflow approved forapplication with kw size heater installed. If no heater is installed,skip this step. Each select pin is marked with a range of heaters forwhich airflow (also marked) is approved. For increased comfortselect the narrowest kw range matching the heater size, forexample, 0-10 for a 10-kw heater. This airflow must be greaterthan the minimum CFM for electric heater application with thesize system installed for safe and continuous operation. Note thatairflow marked is the airflow which will be supplied in emergencyheat mode and heating mode on air conditioners when electric heatis primary heating source. To ensure safe heater operation in heatpump heating mode when electric heaters are energized, the ICM2

Fig. 16—Easy Select BoardA94076

EASY SELECT

GROUNDSCREW

REQUIRED

L

R

C

O

Y/Y2

Y1

GE

CES0130007–00

D8 D7 D5 D6

P1

D1

D2 D9 D4

R2HEATER

240VAC

T2

T3

M2

M1

T1XFORM

MOTOR

240VAC

SEC2 SEC1

24VAC

D3

P2

R3

JW3

JW4

AUX2

AUX1 HUM1

HUM2

24VDC

JW1

JW2D11

R1

CES

S430

023–

01C

EBD

4300

23–0

1

D10

FS1

5 AMPMAX ST1

RED

MOTOR

AMP 12-PIN MATE-N-LOCKCONNECTOR (1)

3⁄16-IN. MALEFASTON

AMP–TYP(21) PLCS

MOLEX 7-PINCONNECTOR (1)

LOW VOLTAGETERMINAL BLOCK

W2-E JUMPER3RD STAGE

W2

W3 W2-W3 JUMPER2ND STAGE

PRINTED CIRCUITBOARD

1⁄4-IN. MALEFASTONAMP–TYP(9) PLCS

AUX HEAT RANGE

AC/HP SIZE

TYPE

AC/HP CFM ADJUST

DELAYAC/HP TIMEENH

VIO

ORN

BLK

GRY

BLU

ON

OFF

0

90

30

90

0

0

HIMEDLO

HP-EFFHP-COMFORTAC

KW

CFM

0-30

1200

0-20

1000

0-10

800

0-5

600

042 036 030 024

5

—22—

will run the higher of heat pump efficiency airflow and electricheater airflow. The factory selection is largest heater rangeapproved. (See Fig. 16.)

B. AC/HP Size

The factory setting for air conditioner or heat pump size is largestunit meant for application with model of fan coil purchased. Theinstaller needs to select air conditioner or heat pump size to ensurethat airflow delivered falls within proper range for size of unitinstalled in all operational modes. (See Fig. 16.)

C. System Type

The type of system must be selected.

1. AC—air conditioner

2. HP-COMFORT—provides same airflow as air conditionerselection (approximately 375 CFM/ton)

3. HP-EFF—provides most efficient airflow for heating andcooling modes (approximately 410 CFM/ton heating and375 CFM/ton cooling)

The factory setting is AC. (See Fig. 16.)

D. AC/HP CFM Adjust

Select low, medium, or high airflow. To provide any of theseairflows, AC/HP ADJUST select must be moved to MED position.The factory selection is LO. The adjust selections HI/LO willregulate airflow supplied for all operational modes, except non-heat pump heating modes, +10 percent and -10 percent respec-tively. The adjust selection options are provided to adjust airflowsupplied to meet individual installation needs for such things asnoise, comfort, and humidity removal. (See Fig. 16.)

E. AC/HP Time Delay

Select desired time delay profile. Four motor operation delayprofiles are provided to customize and enhance system operation.(See Fig. 16.) The selection options are:

1. The standard 90 sec off delay (factory setting).

2. No delay option used for servicing unit or when a thermo-stat is utilized to perform delay functions.

Fig. 17—Easy Select Board CircuitryA94077

ST1

E8

ST1

W29

ST1

W310

ST1

C3

ST1

R2

ST1

G7

ST1

Y/Y25

ST1

Y14

ST1

L1

ST1

O3

JW2

JW1

JW3

JW4

D1

D2

D2

R3

1K 2W

SEC1

SEC2 PS1

R2

1K 2W

R1

1K 2W

P11 2 3

4 5 6

7 8 9

10 11 12

HIGH VOLTAGE

M1

T1

T2

M2

T3

AUX1

HUM1

AUX2

HUM2

D7

D8

D9

D4

D5

D6

P2

W/W1GC1C2RY/Y2Y1

D11

D10

5 – 301200

5 – 201000

5 – 10800

0 – 5600

REDQC19

QC4

QC8

QC3

QC7

QC2

QC6

QC1

QC5

024030036042

QC9

AC

QC12

QC15

ONOFF

LOW

090

QC13MED

QC10HP–COM.

QC11HP–EFF.

QC14HI

QC16

3090

QC17

3030

QC18

00

AUX. HEATRANGE

AC/HPSIZE

AC/HPTYPE

AC/HPCFM TRIM

AC/HPDELAY

—23—

3. A 30 sec on/90 sec off delay profile used when it isdesirable to allow system coils time to heat up/cool downprior to airflow. This profile will minimize cold blow inheat pump operation and could enhance system efficiency.

4. ENH, enhanced selection provides a 30 sec on/180 sec offdelay at half airflow, adding comfort and efficiency.

V. TROUBLESHOOTING PCB

Use Fig. 17 and 18 and Tables 3, 4, and 5 as guides introubleshooting PCB unless otherwise noted.

A. If Fan Will Not Turn On From Thermostat:

IF THERE IS NO HIGH VOLTAGE TO PCB:

1. Check connection of 12-pin plug from heaters to receptacleon Easy Select board. This supplies power to PCB. Be sureplug is connected properly.

2. Check sequencer number 1 and plug wiring. Yellow wireshould be connected to pin number 9 of plug and to limitswitch. Black wire should be connected to pin number 7 ofplug and to sequencer number 1.

TABLE 3—MALE/FEMALE QUICK-CONNECT TERMINALS (FK4B)

SIZE FEMALE SIZE MALE DESCRIPTION

0.250 X 0.032

M2 Motor line voltage connection (230 vac 60 Hz)T3 Transformer line voltage connection (230 vac 60 Hz)T2 Transformer tap storage terminal for 208-vac lead

SEC1 Secondary connection from transformer (24 vac)This connection is common to chassis ground through eyelet marked GROUND SCREW REQUIRED.SEC2 Secondary connection from transformer (24 vac)HUM1 Low voltage ground for humidifier option (24 vdc)HUM2 Low voltage output for humidifier option (24 vdc)AUX1 Low voltage ground for auxiliary option (24 vdc)AUX2 Low voltage output for auxiliary option (24 vdc)

0.187 X 0.032M1 Common connection to blower motorT1 Common connection for transformer

RED Common to R screw terminal and SEC2

TABLE 4—CONNECTIONS ON SINGLE BARRIER STRIP MOUNTED, CROSS SLOTTED, CAPTIVE BINDING HEAD (FK4B)

SCREWTERMINAL DESCRIPTION

W2 Connection for W2 signal from thermostatW3 Connection for W3 signal from outdoor thermostatE Connection for E signal from thermostat

Y/Y2 Connection for Y signal from thermostatG Connection for G signal from thermostatO Connection for O signal from thermostat

L This connection is a field termination for use in connecting L lines of thermostat and outdoor unit together. There is noconnection of this terminal with control circuity.Y1 Connection for low-speed compressor operationR Connection for R signal to thermostat (24 vac)C Connection for C terminal to thermostat (24 vac common)

TABLE 5—CONNECTIONS AND CONNECTOR (FK4B)

TYPECONNECTION

TYPECONNECTOR PIN NO. DESCRIPTION

HeaterConnection 12-Pin

Pin 1 Common to E screw terminalPin 2 Common to W2 screw terminalPin 3 Common to C screw terminal, SEC1 terminal, and chassis groundPin 4 Common to C screw terminal, SEC1 terminal, and chassis groundPin 5 No connectionPin 6 Common to W3 screw terminalPin 7 Common to M2 and T3 quick-connects, 230 vac inputPin 8 No connectionPin 9 Common to M1 and T1 quick-connects, 230 vac input

Pin 10 No connectionPin 11 No connectionPin 12 No connection

ICM2 Motor 7-Pin Header

Pin 1 Diode OR output of E or W3 or W2 thermostat signalsPin 2 Thermostat G signalPin 3 Common to C, SEC1, and chassis groundPin 4 Common to C, SEC1, and chassis groundPin 5 Common to R and SEC2 (via 5-amp fuse)Pin 6 Thermostat Y/Y2 signalPin 7 Thermostat Y1 signal

—24—

Fig. 18—FK4B Wiring DiagramA94078

LSICMTRANGNDFURECPCBF


(SEE NOTE 1)

FIELD POWER WIRING

YEL

GND


DISCONNECT PER NEC

THIS COMPARTMENT MUST BE CLOSED EXCEPT FOR SERVICINGNOT SUITABLE FOR USE ON SYSTEMS

EXCEEDING 150V TO GROUND

CAUTION:

ATTENTION:NE CONVIENT PAS AUX INSTALLATIONS

DE PLUS DE 150 V A LA TERRE

BLOWER MOTORROTATION

HVTB

SEQ 3

CB/FU4

FU6YEL

YEL

YEL

L1

12 11BLK BLK

FU5

8 7

CB/FU2 CB/FU1

YEL YEL 4 3BLK BLK

10 9BLKBLK

SEQ 2

6 5

YEL 2 1BLK

CB/FU3

L2

HTR6

HTR5

HTR4

HTR3

HTR2

HTR1

LS6

LS5

LS4

LS3

LS2

LS1

BLK

SEQ 1

YEL

YEL

BLK BLK

BLK BLK

BLK

BLK

BLK

BLU

BLKYEL

BLU

PLUG 1 RED

GRY

BR

NB

RN

SEQ1

SEQ2

SEQ3

ORN VIO

123456789101112

24567

FIELD POWER WIRING DISCONNECT PER NEC

SCHEMATIC DIAGRAM


(SEE NOTE 1)YEL BLK

9 7

GND

COOLING CONTROL WIRING

COOLING CONTROL ONLY

AUX HEAT RANGE

AC/HP SIZE

TYPEA–C HP–COMFORT HP–EFF

AC/HP CFM TRIM

AC/HP DELAY ON/OFF0/30 30/30 30/30 0/0

7

RECP 21

TRAN

COMMON

BRN

RED

BLK

RED

GRY

BLK

ORN

BLU

VIO

1

2

3

4

5

6

7

8

9

10

11

12

RECP 1

REDBLU

RED

M1

M2

T1

SEC2

SEC1

T2

T3 PCB

PLUG

24VAC

LVTB

JW2

JW1

L

R

C

O

G

E

W2

W3

GRN/YEL

YEL

BLK

5 4 3 2 1

PLUG 3

PLUG 4

YEL

RECP 3

RECP 4

ICMBRNYEL

REDVIO

REDORN

BRNVIO

ORNGRY

BLUBLK

BLK

1

9

2

10

3

11

4

12

5

13

6

14

7

15

8

16

PLUG 2

BLK

YEL ORN GRN

RED BRN VIO

(SEE NOTE 3)

(SE

E N

OT

E 2

)

service manual - justanswer...this symbol →indicates a change since the last issue. safety...

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