large vertical water source heat pumps 6 thru 25 tons

ContentsModel Nomenclature ..................................................... 2Transportation and Storage .......................................... 2Installation ................................................................... 3-6Piping ............................................................................. 7Cleaning and Flushing System ...................................... 8Start-up ....................................................................... 8-9Operating Limits ............................................................ 9Electrical Data ................................................................ 9Typical Wiring Diagrams .........................................10-13

Typical Mark IV/AC units .................................... 10-11

Typical MicroTech units ................................... 12-13Unit Operation ............................................................. 14Thermostat Connections ....................................... 15-16Miscellaneous Options on Mark IV Units .............. 17-20Field Installed Options on MicroTech Units ................ 21Troubleshooting ........................................................... 22Maintenance ................................................................ 23

Installation & Maintenance Data IM 439-12

Group: WSHP

Part Number: 107224201

Date: October 2000

Large Vertical Water Source Heat Pumps6 thru 25 Tons

©2000 AAF-McQuay Incorporated IM 439-12 (Rev. 10/00)

/ IM 439

©2000 McQuay International

Note: Installation and maintenance are to be performed onlyby qualified personnel who are familiar with local codes andregulations, and are experienced with this type of equipment.

Sharp edges are a potential injury hazard. Avoid contact withthem.

Transportation and StorageUpon receipt of the equipment, check unit for visible damage.Make a notation on the shipper’s delivery ticket before signing.If there is any evidence of rough handling, the cartons shouldbe opened at once to check for concealed damage. If anydamage is found, notify the carrier within 48 hours to estab-lish your claim and request their inspection and a report. TheWarranty Claims Department should then be contacted.

Do not stand or transport the machines on end. For storing,each unit must be in the “up” position.

In the event that elevator transfer makes upended position-ing unavoidable, absolutely insure that the machine is in thenormal upright position for at least 24 hours before operating.

Temporary storage at the jobsite must be indoors, com-pletely sheltered from rain, snow, etc. High or low tempera-tures naturally associated with weather patterns will notharm the conditioners. Excessively high temperatures 140°F(60°C) may deteriorate certain plastic materials and causepermanent damage. In addition, the solid-state circuit boardsmay experience operational problems.

! CAUTION

Model NomenclatureW LDD 1 070 D Z

Product CategoryW = WSHP

Product IdentifierSee box below

Design Series1 = A Design2 = B Deisgn3 = C Design4 = D Design5 = E Design

Nominal Capacity070 = 70,000108 = 108,000121 = 121,000180 = 180,000215 = 215,000290 = 290,000etc. . .

Coil Options(None)

VoltageD = 208-60-3H = 230-60-3K = 460-60-3L = 575-60-3N = 380-50-3

McQuay Product Identifiers

LDD = Std. Large Vertical/DDC Controls/Std. Range/Less Board LME = Std. Large Verical/Mark IV/Ext. RangeLDE = Std. Large Vertical/DDC Controls/Ext. Range LMH = High Static Large Vertical/Mark IV/Std. RangeLDL = Std. Large Vertical/DDC Controls/Ext. Range/Less Board LML = High Static Large Vertical/Mark IV/Ext. RangeLDS = Std. Large Vertical/DDC Controls/Std. Range LMS = Std. Large Vertical/Mark IV/Std. Range

IM 439 /

Control BoxLocation

PipingLocation

Fan Motor

24"(610 mm)

Side B

Side A

24" (610 mm)

InstallationGeneral

1. To prevent damage, this equipment should not be oper-ated for supplementary heating and cooling during theconstruction period.

2. Inspect the shipping label for any specific tagging numbersindicated per request from the installing contractor. At thistime the voltage, phase and capacity should be checkedagainst the plans.

3. Check the unit size against the plans to be sure that the unitwill be installed in the correct location.

4. After removing the packaging material, remove unit fromthe skid.

5. Before installation, check the available dimensions versusthe dimensions of the unit.

6. Pay attention to the location and routing of water piping,condensate drain piping, and electrical wiring. The loca-tions of these items are clearly marked on submittaldrawings.

7. The installing contractor will find it beneficial to confer withpiping, sheetmetal, ceiling and electrical foremen togetherbefore installing any conditioners.

8. We recommend that the contractor cover the conditionerswith plastic film to protect the machines during finishing ofthe building. This is important if spraying fireproofingmaterial on bar joists, sandblasting, spray painting andplastering operations have not been completed.

Figure 1. Service clearance

1. A 24" (610 mm) minimum clearance is required on the return air, control boxand piping sides. However, a 36" (914 mm) clearance allows for easierserviceability.

2. A 12" (305 mm) minimum clearance is required on Side A to gain accessto panel to remove locking collar for shaft removal.

3. A 6" (152 mm) minimum clearance is required to remove screws holdingtop panel.

4. Top clearance is required for fan shaft removal.

5. Some codes dictate a 60" (1524 mm) clearance above the control boxwhich could be violated with a ducted return. Check your codes.

Figure 2. Side view from piping end

Filter AccessEach unit is shipped with a filter bracket for side filter removal.

Unit ArrangementTwo fan discharges and piping arrangements are available.With the return air side defined as the “front” of the unit, thewater piping and electrical power connections may be right-hand (side) or left-hand. The main control panel is located inthe center of the unit, lower section under the return air filter.Unit sides opposite the control panel and opposite the pipingside may be up against walls and still allow for service andmaintenance through the remaining access panels.

Unit Location1. Locate the unit in an area that allows for easy removal of the

filter and access panels, and has enough space for servicepersonnel to perform maintenance or repair. Provide suf-ficient room to make water, electrical and duct connections(see Figure 1 for service clearance details).

2. The contractor should make sure that access has beenprovided including clearance for 2" (51 mm) thick filterbrackets, duct collars and fittings at water and electricalconnections.

3. Allow adequate room around the unit for a condensate trap.

4. The unit can be installed “free standing” in an equipmentroom. Generally, the unit is located in a separate room withthe non-ducted return air facing the return air intake.Alternatively, the unit can have a ducted return air.

5. It is recommended that the unit be located on vibrationisolators to reduce any vibration (see Figure 3).

6. If optional field installed controls are required (BoilerlessSystem), space must be provided for the enclosure tomount on the side of the unit.

Fan Motor

M

Control Box Location

M

PipingPiping

/ IM 439

Vibration IsolationFor minimum sound and vibration transmission, it is recom-mended that the unit be mounted on vibration isolators.

Holes are provided in the bottom panel to facilitate connec-tion of isolators (see Figure 3 for hole locations).

Isolators supplied by the manufacturer are the type shownin Figures 4 and 5. Four white isolators are used for singlecompressor units and six green isolators are used for dualcompressor units. The holes in the bottom of the unit allow fora 3⁄8" (10 mm) bolt to be secured to the isolator.

Figure 3. Isolator

3" (76 mm)

3" (76 mm)

3" (76 mm)

3" (76 mm)

(4) 7/16" (11 mm) holes

A

7/16" (11 mm)

1/4" (6 mm)

A

2"(51 mm)

285/32"(715 mm)

5423/32" (1390 mm)

Section A-A

Figure 4. Single compressor unit — vibration isolators

Figure 5. Dual compressor unit — vibration isolators

2" (51 mm)

31/4" (83 mm)

2" (51 mm)

31/4" (83 mm)

(6) 3/8" (10 mm) holes

301/8"(765 mm)

803/8" (2042 mm)

403/16" (1021 mm)

3/8" (10 mm) TAP

7/16" (11 mm) dia.

21/2" (64 mm)

41/2" (114 mm)

51/2" (140 mm)

25/8" (61 mm)

IM 439 /

Air BalancingAll units are supplied with a variable pitch motor sheave to aidin airflow adjustment. They are typically set at the low end ofthe rpm range for field adjustment to the required airflow.

When the final adjustments are complete, the current drawof the motors should be checked and compared to the full loadcurrent rating of the motors. The amperage must not exceedthe service factor stamped on the motor nameplate.

Upon completion of the air balance, it is a commonindustry recommendation that the variable pitched motorsheave be replaced with a properly sized fixed sheave. Amatching fixed sheave will provide longer belt and bearing lifeand vibration free operation. Initially, it is best to have avariable pitched motor sheave for the purpose of air balancing,but once the balance has been achieved, fixed sheavesmaintain balancing and alignment more effectively.

Adjustment (See Figure 6)Figure 6.

Figure 7. Drive belt adjustment

1. All sheaves should be mounted on the motor or drivingshaft with the setscrew “A” toward the motor.

2. Be sure both driving and driven sheaves are in alignmentand that shafts are parallel.

3. Fit internal key “D” between sheave and shaft, and locksetscrew “A” securely in place.

Adjusting:1. Loosen setscrews “B” and “C” in moving parts of sheave

and pull out external key “E”. (This key projects a smallamount to provide a grip for removing.)

2. Adjust sheave pitch diameter for desired speed by open-ing moving parts by half or full turns from closed position.Do not open more than five full turns.

3. Replace external key “E” and securely tighten setscrews“B” over key and setscrews “C” into keyway in fixed half ofthe sheave.

4. Put on belts and adjust belt tension to 4 lbs. ± 0.7 lbs.(18 ± 3N) for a 1⁄2" to 3⁄4" (13 mm to 19 mm) belt deflectionheight.

5. To determine the deflection distance from normal position,use a straightedge or stretch a cord from sheave to sheaveto use as a reference line. On multiple-belt drives an adjacentundeflected belt can be used as a reference.

6. Future adjustments should be made by loosening the belttension and increasing or decreasing the pitch diameter ofthe sheave by half or full turns as required. Readjust belttension before starting drive.

7. Be sure that all keys are in place and that all setscrews aretight before starting drive. Check setscrews and belt tensionafter 24 hours service.

8. When new V-belts are installed on a drive, the initialtension will drop rapidly during the first few hours. Checktension frequently during the first 24 hours of operation.Subsequent retensioning should fall between the mini-mum and maximum force.

“E”

“B”

“D”

“C”

“A”

Single Groove

Key “E” projects toprovide a grip forremoving.

h = t64

t = C2 – D-d√ 2( )Where:t = Span length, inches (mm)C = Center distance, inches (mm)D = Larger sheave diameter, inches (mm)d = Smaller sheave diameter, inches (mm)h = Deflection height, inches (mm)

Note: The ratio of deflection to belt span is 1:64.

DeflectionForce

h

D

d

Span Length (t)

C

/ IM 439

Ductwork and AttenuationDischarge ductwork is normally used with these conditioners.Return air ductwork may also be required but will require fieldinstallation of a return air duct collar.

All ductwork should conform to industry standards of goodpractice as described in ASHRAE Systems Guide.

The discharge duct system will normally consist of aflexible connector at the unit, a transition piece to the final ductsize, a short run of duct, an elbow without vanes and a trunkduct tee’d into branch ducts with discharge diffusers asshown in Figure 10. Transition piece must not have anglestotalling more than 30 degrees or severe loss of air perfor-mance can result.

All units have multiple fan outlets. A single duct can encloseall the openings as shown in Figure 10; however, the preferred

method for minimum static pressure loss would be individualducts at each outlet connected to a larger duct downstream.

For minimum noise transmission, the metal duct materialshould be internally lined with acoustic fibrous insulation.

The ductwork should be laid out so that there is no line ofsight between the conditioner discharge and the distributiondiffusers.

Return air ducts can be brought in adjacent to the return airof the conditioner. Typically, the equipment room becomes thecommon return air plenum.

Do not insert sheetmetal screws directly into the unitcabinet for connection of supply or return air ductwork,especially return air ductwork which can hit the drain pan orthe air coil.

Ventilation AirOutside air may be required for ventilation. The temperatureof the ventilation air must be controlled so that mixture ofoutside air and return air entering the conditioner does notexceed conditioner application limits. It is also general prac-tice to close off the ventilation air system during unoccupiedperiods (night setback).

The ventilation air system is generally a separate building

subsystem with distribution ductwork. Simple introductionof the outside air into each return air plenum chamberreasonably close to the conditioner air inlet is not onlyadequate, but recommended. Do not duct outside air directlyto the conditioner inlet. Provide sufficient distance for thor-ough mixing of outside and return air (see Operating Limits onpage 9).

Optional Duct Collar and 2" (51 mm) Filter RackThe optional duct collar kit is used to facilitate connection ofreturn air duct to the unit. The duct collar kit can be used inconjunction with the standard 1" (25 mm) thick filter rack or theoptional 2" (51 mm) filter rack.

The 2" (51 mm) filter rack facilitates the installation of 2"(51 mm) thick filters for side removal. The 2" (51 mm) filterrack replaces the existing 1" (25 mm) filter rack and does notrequire the use of the optional return air duct collar.

The kits are installed as follows:

1. Remove all filters, filter racks and brackets. Save all screws.Discard bracket end.

2. Attach top duct collar in conjunction with top filter rack withtruss head screws.

3. Attach bottom duct collar and filter rack.

4. On single compressor units, attach two flanges using four(4) #8 truss head screws provided.

5. Attach center support in original location.

6. Locate and attach center filter racks using screws provided.

7. Attach duct collar sides using eight (8) #10 sheetmetalscrews provided.

8. Attach one door end to either side of unit with #10 sheetmetalscrews.

9. Slide filters into position.

10. Attach other door end side cover.

Figure 8. Assembly detail

Duct Collar Side

DuctCollar

FilterRack

IM 439 /

Figure 9.

Center Support

Chassis

Door End

Duct Collar Side

Center Filter Racks

Side Flanges

Top Duct Collar

Top Filter RackFilters

Piping1. All units are recommended to be connected to supply and

return piping in a two-pipe reverse return configuration. Areverse return system is inherently self-balancing andrequires only trim balancing where multiple quantities ofunits with different flow and pressure drop characteristicsare connected to the same loop. A simple way to check forproper water balance is to take a differential temperaturereading across the water connections. To insure properwater flow, the differential should be 10°F to 14°F (5°C to8°C) in the cooling mode of operation.

A direct return system may also be made to workacceptably, but proper water flow balancing is moredifficult to achieve and maintain, and may require flowcontrol devices.

2. The piping can be steel, copper or PVC.

3. Supply and return runouts are usually connected to theunit by short lengths of high pressure flexible hose whichare sound attenuators for both unit operating noise andhydraulic pumping noise. One end of the hose shouldhave a swivel fitting to facilitate removal for service. Hardpiping can also be brought directly to the unit although itis not recommended since no vibration or noise attenu-ation can be accomplished. The hard piping must haveunions to facilitate unit removal (see Figure 10 for typicalpiping setup).

4. Supply and return shutoff valves are required at eachconditioner. The return valve is used for balancing andshould have a “memory stop” so that it can always beclosed off but can only be reopened to the proper positionfor the flow required.

5. No unit should be connected to the supply and returnpiping until the water system has been cleaned andflushed completely. After the cleaning and flushing hastaken place, the initial connection should have all valveswide open in preparation for water system balancing.

6. Condensate piping can be steel, copper or PVC. Eachunit is supplied with a FPT threaded fitting.

Figure 10.

7. The condensate disposal piping must have a trap and thepiping must be pitched away from the unit not less than1⁄4" per foot (21 mm per meter). Generally, the condensatetrap is made of copper. A complete copper or PVC conden-sate system can also be used. Union fittings in the copperlines should be applied to facilitate removal.

8. No point in the drain system may be above the drainconnection of any unit.

9. Automatic flow controlled devices must not be installedprior to system cleaning and flushing.

10. A high point of the piping system must be vented.

11. Check local code for the need of dielectric fittings.

FlexibleConnector

TransitionDuct

MainDuct

BranchDuct

Trunk Duct

Flexible Hosewith BrassPipe Fittings

Supply

Return

BalancingValve withClose-off

Condensate

Note: Do not overtorque fittings. The maximum torque without damage to fittings is 30 foot pounds. If a torque wrench is not available, use as a rule of thumb,finger-tight plus one quarter turn. Use two wrenches to tighten the union, one to hold the line and one for simultaneous tightening of the nut.

/ IM 439

Cleaning and Flushing System1. Prior to first operation of any conditioner, the water

circulating system must be cleaned and flushed of allconstruction dirt and debris.

If the conditioners are equipped with water shutoffvalves, either electric or pressure operated, the supply andreturn runouts must be connected together at each condi-tioner location. This will prevent the introduction of dirt intothe unit. Additionally, pressure operated valves only openwhen the compressor is operating (see Figure 11).

Figure 11.

2. The system should be filled at the city water makeupconnection with all air vents open. After filling, vents should beclosed.

The contractor should start main circulator with pres-sure reducing valve makeup open. Vents should be checkedin sequence to bleed off any trapped air to assure circula-tion through all components of the system.

Power to the heat rejector unit should be off, and thesupplementary heat control set at 80°F (27°C).

While circulating water, the contractor should checkand repair any leaks in the piping. Drain at the lowestpoint(s) in the system should be opened for initial flush andblowdown, making sure city water fill valves are set tomake up water at the same rate. Check the pressuregauge at pump suction and manually adjust the makeup tohold the same positive steady pressure both before andafter opening the drain valves. Flush should continue for atleast two hours, or longer if required, to see clear, cleandrain water.

3. Supplemental heater and circulator pump should be shutoff. All drains and vents should be opened to completelydrain down the system. Short circuited supply and returnrunouts should now be connected to the conditioner supplyand return connections. Teflon tape is recommended overpipe dope for pipe thread connections. Use no sealers at theswivel flare connections of hoses.

4. Trisodium phosphate was formerly recommended as acleaning agent during flushing. However, many states andlocalities ban the introduction of phosphates into their sew-age systems. The current recommendation is to simplyflush longer with warm 80°F (27°C) water.

5. Refill the system with clean water. Test the litmus paper foracidity, and treat as required to leave the water slightlyalkaline (pH 7.5 to 8.5). The specified percentage of anti-freeze may also be added at this time. Use commercialgrade anti-freeze designed for HVAC systems only. Do notuse automotive grade anti-freeze.

6. Set the system control and alarm panel heat add setpointto 70°F (21°C) and the heat rejection setpoint to 85°F(29°C). Supply power to all motors and start the circulatingpumps. After full flow has been established through allcomponents including the heat rejector (regardless of sea-son) and air vented and loop temperatures stabilized, eachof the conditioners will be ready for check, test and start-up and for air and water balancing.

Start-up1. Open all valves to full open position and turn on power to

the conditioner.

2. Set thermostat for Fan Only operation by selecting Off atthe system and On at the fan switch. If Auto fan operationwere selected, the fan would cycle with the compressor.Check for proper air delivery.

3. All units have variable pitch motor sheaves. Reset forcorrect airflow.

4. Set thermostat to Cool. If the thermostat is an automaticchangeover type, simply set the cooling temperature tothe coolest position. On manual changeover types addi-tionally select Cool at the system switch.

Again, many conditioners have time delays whichprotect the compressor against short cycling. After a fewminutes of operation, check the discharge grilles for coolair delivery. Measure the temperature difference betweenentering and leaving water. It should be approximately 11⁄2times greater than the heating mode temperature differ-ence. For example, if the cooling temperature differenceis 15°F (8°C), the heating temperature difference shouldhave been 10°F (5°C).

Without automatic flow control valves, a cooling tem-perature difference of 10°F to 14°F (5°C to 8°C) is about

right. Adjust the combination shutoff/balancing valve inthe return line to a water flow rate which will result in the10°F to 14°F (5°C to 8°C) degree difference in cooling.

5. Set thermostat to Heat. If thermostat is the automaticchangeover type, set system switch to the Auto positionand depress the heat setting to the warmest selection.Some conditioners have built-in time delays which pre-vent the compressor from immediately starting. Withmost control schemes, the fan will start immediately. Aftera few minutes of compressor operation, check for warmair delivery at discharge grille. If this is a “cold building”start-up, leave unit running until return air to the unit is atleast 65°F (18°C).

Measure the temperature difference between enteringand leaving air and entering and leaving water. Withentering water of 60°F to 80°F (16°C to 27°C), leavingwater should be 6°F to 12°F (3.3°C to 6.6°C) cooler, andthe air temperature rise through the machine should notexceed 35°F (19°C). If the air temperature exceeds 35°F(19°C), the airflow rate is probably inadequate.

If the water temperature difference is less than 6°F(3.3°C) degrees, the water flow rate is excessive. If thewater temperature difference exceeds 12°F (6.6°C), thenthe water flow rate is inadequate.

Return Runout

Supply Runout

Mains

Rubber Hose

Runouts InitiallyConnected Together

IM 439 /

6. Check the elevation and cleanliness of the condensateline. If the air is too dry for sufficient dehumidification,slowly pour enough water into the condensate pan toensure proper drainage.

7. If the conditioner does not operate, the following pointsshould be checked:a. Is proper voltage being supplied to the machine?b. Is the proper type of thermostat being used?c. Is the wiring to the thermostat correct?

8. If the conditioner operates but stops after a brief period,check for:a. Is there proper airflow? Check for dirty filter, incorrect

fan rotation (3-phase fan motors only), or incorrectductwork.

b. Is there proper water flow rate within temperature limits?Check water balancing; backflush unit if dirt-clogged.

9. Check the unit for vibrating refrigerant piping, fan wheels,etc.

10. Do not lubricate the fan motor during the first year ofoperation as it is prelubricated at the factory.

Electrical DataGeneral

1. Be sure the available power is the same voltage and phaseas that shown on the unit serial plate. Line and low voltagewiring must be done in accordance with local codes or theNational Electrical Code, whichever is applicable.

2. Apply correct line voltage to the unit. Each unit is suppliedwith a 3-lug terminal block in the main control for three-

phase main power. Multiple knockouts on the sides of theunit facilitate conduit connections on the unit for line andlow voltage. A disconnect switch near the unit is requiredby code. Power to the unit must be sized correctly and befused with Class RK5 dual element fuses.

This equipment is designed for indoor installation only. Shel-tered locations such as attics, garages, etc., generally will notprovide sufficient protection against extremes in temperature

and/or humidity, and equipment performance, reliability,and service life may be adversely affected.

Table 1. Air and water limits

All UNITS

Cooling HeatingMin. Ambient Air 40°F/5°C 40°F/5°C

Normal Ambient Air 80°F/27°C 70°F/21°CMax. Ambient Air 100°F/38°C 85°F/29°CMin. Ent. Air➀ ➁ 50°F/10°C 40°F/5°CNormal Ent. Air, 80/67°F 70°F

db/wb 27/19°C 21°CMax. Ent. Air, 100/83°F 80°F

db/wb➀ ➁ 38/28°C 27°C

Table 2. Water enthalpy

Cooling Heating Cooling HeatingMin. Ent. Air➀ ➁ 55°F/13°C 55°F/13°C 40°F/5°C 40°F/5°CNormal Ent. Air 85°F/29°C 70°F/21°C 85°F/29°C 70°F/21°CMax. Ent. Air➀ ➁ 110°F/43°C 90°F/32°C 110°F/43°C 90°F/32°C

➀ At ARI flow rate.➁ Maximum and minimum values may not be combined. If one value is at

maximum or minimum, the other two conditions may not exceed the normalcondition for standard units. Extended range units may combine any twomaximum or minimum conditions, but not more than two, with all otherconditions being normal conditions.

Operating LimitsEnvironment

Additional Information1. All units

Unit will start and operate in an ambient of 40°F (5°C), withentering air at 40°F (5°C), with entering water at 40°F(5°C), with both air and water at flow rates used in the ARIStandard 320-86 rating test, for initial start-up in winter.

Note: This is not a normal or continuous operating condition.It is assumed that such a start-up is for the purpose ofbringing the building space up to occupancy temperature.

Minimum and Maximum VoltageNameplate 208/60/3: Min. 187 volts, Max. 229 voltsNameplate 230/60/3: Min. 207 volts, Max. 253 voltsNameplate 460/60/3: Min. 414 volts, Max. 506 voltsNameplate 575/60/3: Min. 515 volts, Max. 632 voltsNameplate 380/50/3: Min. 360 volts, Max. 418 volts

Note: Three-phase system unbalance should not exceed 2%.Voltages listed are to show voltage range. However, units operatingwith overvoltage and undervoltage for extended periods of time willexperience premature component failure.

/ IM 439

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/ IM 439

Figure 14. Typical MicroTech unit — single compressor

LEGEND

ComponentWire ConnectorThermistor

Heater Crankcase HeaterOptional Wiring

LP1 Low pressure SwitchHP1 High Pressure SwitchLT1 Low Temperature SwitchRV Reversing Valve SolenoidM2 Compressor ContactorM1 Fan Starter

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IM 439 /

Figure 15. Typical MicroTech unit — dual compressor

LEGEND

ComponentWire ConnectorThermistor

Heater Crankcase HeaterOptional Wiring

V1 & V2 Expansion ValveR1, R2 & R3 Relay

M2 & M3 Compressor ContactorT1 & T2 Transformer

RV1 & RV2 Reversing Valve SolenoidLP1 & LP2 Low pressure SwitchHP1 & HP2 High Pressure SwitchLT1 & LT2 Low Temperature Switch

M1 Fan StarterTB Terminal Block Connection

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Heater(Ext. Rng. Only)

Heater(Ext. Rng. Only)

Terminal Board #1

(optional)

/ IM 439

Unit OperationGeneral

Each unit has a printed circuit board control system. The lowvoltage output from the low voltage terminal strip on the controlboard is always 24 volts DC (direct current). Terminals C andR on the low voltage terminal strip supply 24 volts AC power.

The unit has been designed for operation with a 24 voltmercury bulb type wall thermostat or a microelectronic wallthermostat selected by the manufacturer. Do not operate theunit with any other type of wall thermostat.

Mark IV/AC Control UnitsSingle compressor units have a single Mark IV/AC circuitboard and dual compressor units have two Mark IV/AC circuitboards. The refrigerant circuits on dual compressor unitsoperate totally independent from each other and allow fortotal independent operation of each circuit.

The Mark IV/AC circuit board has built-in features such asrandom start, compressor time delay, night setback, loadshed, shutdown, condensate overflow protection, defrostcycle, brownout, and LED/fault outputs.

The 24 volt low voltage terminal strip on each board is setup so R-G energizes the fan, R-Y1 energizes the compressorfor cooling operation, R-W1 energizes the compressor andreversing valve for heating operation. The reversing valve isset up to be energized in the heating mode. The circuit boardhas a fan interlock circuit to energize the fan whenever thecompressor is on if the thermostat logic fails to do so.

The Mark IV/AC control board has a lockout circuit to stopcompressor operation if any one of its safety switches opens(high pressure switch and low pressure switch). If the lowtemperature switch opens, the unit will go into the coolingmode for 60 seconds to defrost any slush in the water-to-refrigerant heat exchanger. After 60 seconds the compressoris locked out. If the condensate sensor detects a filled drainpan, the compressor operation will be suspended only in thecooling mode. The unit is reset by opening and closing thedisconnect switch on the main power supply to the unit in theevent the unit compressor operation has been suspendeddue to low temperature (freezestat) switch, high pressureswitch or low pressure switch. The unit does not have to bereset on a condensate overflow detection.

The Mark IV/AC control circuit has a fault output signal toan LED on a wall thermostat. Table 3 shows for which functionsthe fault output is “on” (sending a signal to the LED).

Table 3.

LEDs FAULTINDICATIONYellow Green Red OUTPUT

Normal Mode Off On Off OffHigh Pressure Fault Off Off Flash OnLow Temperature Fault* Flash Off Off OnCondensate Overflow On Dim Off OnBrown-out Off Flash Off OnLoad Shed Off Off On OffUnoccupied Mode On On Off OffUnit Shutdown Off Flash Off On

*In heating mode only.

The Mark IV/AC control circuit has built-in night setbackoperation. A “grounded” signal to the “U” terminal on the lowvoltage terminal strip puts the unit into the unoccupied modefor night setback operation. The fan shuts off and the unit is putunder control from the night setback terminal on the thermo-stat, W2 on single compressor and W3 on dual compressorunits; day heating and cooling operation is locked out. R-W2energizes the compressor and reversing valve for heatingoperation. Night setback operation can be overridden for twohours by toggling the fan switch (intermittently closing the Rto O terminals) on the Deluxe Auto Changeover thermostat.Day thermostat setpoints then control the heating and cool-ing operation. The Mark IV/AC control system is also set upfor load shed and shutdown operation on receipt of a“grounded” signal to the “L” and “E” terminals, respectively,on the low voltage terminal strip (see Figure 16).

Figure 16.

To activate the unoccupied mode for units on the same clock schedule,a single wire can be “daisy chained” between units and simply groundedthrough the timeclock contacts. The same system can also be done toactivate the load shed and emergency shutdown modes by runningadditional wires between units to ground.

The P and C terminals of the Mark IV/AC board are usedfor pump restart. These terminals pass a voltage signalwhenever the unit’s compressor is turned on. This signal isdetected by a Pump Restart Relay board (P/N 898-613703X01)providing a N.O. or N.C. set of contacts for heat pump loopcirculation pump control. When used with the Loop WaterController, the relay operation accommodates turning offcirculation pumps during unoccupied periods with a safetyoverride dependent on, at minimum, one WSHPs need. TheP and C terminals may be “daisy chained” between 200 units(see page 17).

Ground

Unit3

ToAdditional

UnitsTimeClock

Unit2

Unit1

IM 439 /

Thermostat Connection DiagramsMark IV/AC Units – Unit Sizes 007 to 060

Manual Changeover Thermostat (P/N 106069001)

Standard Automatic & Manual Changeover Thermostat (P/N 105570701)

Deluxe Automatic Changeover Thermostat (P/N 105571003)

Non-Programmable Electronic Thermostat (P/N 105570801)

WSHP Mark IV/AC Board Low Voltage Terminal Strip

Thermostat Terminals

P/N 105571003Includes Thermostat and Subbase(Honeywell P/N’s T874C1869 and Q674C1579)Fan Switch: Auto / On / Tenant OverrideSystem Switch: Off / Auto

Note: Thermostat provides a fixed 13°F differential between W1 and W2.

Operation: The units Mark IV/AC boardwill be in the occupied mode,monitoring terminals W1 and Y1 andignoring terminal W2, when the timeclock contacts are open. The Mark IV/AC board will be in the unoccupiedmode, monitoring terminal W2 andignoring terminals W1 and Y1, when thetime clock contacts are closed. Nocooling is allowed during theunoccupied mode. The tenant overridefeature of the thermostat allows theoccupant to force a 2-hour override ofunoccupied mode. During this overrideperiod the W1 and Y1 terminals aremonitored and the W2 terminal isignored (same as occupied).



P/N 105570801Includes Thermostat and Wall Plate(Honeywell P/N T8524D1064)



P/N 105570701Includes Thermostat and Subbase(Honeywell P/N’s T874A1598 and Q674E1460)Fan Switch: Auto / OnSystem Switch: Off / Heat / Auto / Cool



P/N 106069001Includes Thermostat and Subbase(Honeywell P/N T834C2416)Fan Switch: Auto / OnSystem Switch: Heat / Off / Cool

/ IM 439

Programmable Electronic Thermostat (P/N 105570901)

Deluxe Automatic Changeover Thermostat (P/N 105571003)

Non-Programmable Electronic Thermostat (P/N 105570801)

Programmable Electronic Thermostat (P/N 105570901)

Operation: The units Mark IV/AC board will be in the occupiedmode, monitoring terminals W1 and Y1 and ignoring terminal W2,when the time clock contacts are open. The Mark IV/AC boardwill be in the unoccupied mode, monitoring terminal W2 andignoring terminals W1 and Y1, when the time clock contacts areclosed. No cooling is allowed during the unoccupied mode. Thetenant override feature of the thermostat allows the occupant toforce a 2-hour override of unoccupied mode. During this overrideperiod the W1 and Y1 terminals are monitored and the W2terminal is ignored (same as occupied).

P/N 105571003Includes Thermostat and Subbase(Honeywell P/N’s T874C1869 and Q674C1579)Fan Switch: Auto / On / Tenant OverrideSystem Switch: Off / AutoThermostat Terminals


WSHP Circuit 1 Mark IV/AC Board Low Voltage Terminal Strip WSHP Circuit 2 Mark IV/AC Board Low Voltage Terminal Strip










Mark IV/AC — Unit sizes 070 thru 120

IM 439 /

Pump Restart Relay Kit P/N 061419001

Wiring Pump Restart Relay when Installed within the LWC Panel

Wiring Pump Restart Relay when Installed within a WSHP Control Box

Miscellaneous Options on Mark IV Units

Used as an option with the Mark IV/AC board, the pumprestart relay kit provides a means to alert the loop watercontroller that water flow is required by a WSHP so that thesystem pump can be started. This option is typically used ininstallations where the pump may be shut off when there isno need for water flow (i.e. temperature OK, etc.). Typicallyonly one pump restart relay kit is required per installation asup to 200 Mark IV/AC boards can be “daisy-chained” to-gether.

The Mark IV/AC “P” terminal is used to determine WSHPcompressor operation. Wired as shown below, when com-pressor operation is required, the Mark IV/AC “P” terminal

will change state causing a contact closure between terminal58 and 64 signaling the loop water control (LWC) panel torestart the loop pump if Off.

The pump restart relay kit is typically mounted within oneWSHP or within the LWC panel, whichever is more conve-nient, diagrams are provided below for each location. Toinstall the relay, remove the cover on the double-faced tapeprovided on the relay and attach the relay either to the insideof the LWC panel (adjacent to circuit breaker CB1 andterminal block TB3) or in the WSHP control box (in a conve-nient location), then wire as shown below.


LoopWater

ControllerTerminals

Daisy chain to otherMark IV/AC board“P”and “C” terminals

PumpRestartRelay

Note: Make all wiring connections to circuit one (1) board when adding this optionto a dual circuit machine.

WSHP Mark IV/AC Board Low Voltage Terminal Strip (Circuit 1)

/ IM 439

To Low VoltageHole on Unit

Shutoff Valve

To Main System

Conduit Assembly

Motorized ValveAssembly

Flexible Hose

Return Water Connection

12345

Orange to 5

Pin, Male

Plug

Conduit

Anti-ShortBushing

66" (1676 mm)Lead Length

11/4" or 11/2" Valve

Black to 1Red to 2White to 3Yellow to 4

Typical Motorized Valve Installation

Motorized Valve & Relay for Large Vertical UnitsWired as shown below the motorized valve will open on acall for compressor operation. These 1-1⁄4˝ and 1-1⁄2˝ valvesare power-open power-close. Valve and auxiliary relay arepurchased separately.

Note: The wiring shown below can only be used when the “P”terminal is not being used as a pump restart signal to other equip-ment. If the “P” terminal must be used as a pump restart signal toother equipment, then wire the auxiliary relay’s yellow wire to “Y1”,white wire to “W1”, and orange wire to “C”, then the valve will openon a call for occupied heating or cooling from the thermostat.

WSHP Mark IV/AC Board Low Voltage Terminal Strip (Circuit 1)


P/N 105571003Includes Thermostat and Subbase(Honeywell P/N’s T874C1869 and Q674C1579)Fan Switch: Auto / On / Tenant OverrideSystem Switch: Off / Auto


Auxiliary Relay

Daisy-chain toadditional Mark IV/ACboard “U” terminals

COMP SpadeTerminal

(on Circuit 1Mark IV/AC

Board)

COMMONSpade

Terminal (onCircuit 1 Mark IV/

AC Board) CompressorContractor(Circuit 1)

P/N 061201002 - 1-1/4" Valve Kit (070-120)P/N 061201102 - 1-1/2" Valve Kit (180-290)P/N 061201202 - Valve Relay

Note: Wire motorized valve relay to Circuit one (1) on all dual circuitmachines, sizes 180, 215 and 290, as illustrated above.

IM 439 /

Boilerless System Kit (BSK)P/N 062522204 for sizes 070 - 108 and 121P/N 0061251501 for sizes 180, 215 and 290

The BSK option for use with the Mark IV/AC control boardprovides the capability to control a remote duct heater. Theduct heater must be provided with a low voltage controlcircuit that only requires a set of dry contacts for operation.

The contacts shown on the Boilerless System board (termi-nals 1, 2, and 3) are used to control the remote duct heater,the N.O. contacts will close on a call for duct heater heat.POT1 provides a means to manually adjust the water tem-perature setpoint (adjustment range is 43OF to 60OF). TheNormal/Override switch provides a means to manually forceelectric heat to always be used in place of heat pump heatwhen in the override position (default position is normal - heatpump heat).

When the water temperature drops below the value of POT1,then the duct heater will be used instead of heat pump heaton a call for heat from the low voltage thermostat (notincluded).

The BSK field installed kits include the sheet metal enclosurewith cover, wire harness, boilerless system board, auxiliaryrelay, and water temperature sensor. When used, one BSK isrequired for each unit. To use the BSK kit you attach the sheetmetal enclosure to the unit as shown, route the 4-wireharness through knockouts and connect to the Mark IV/ACboard, mount and connect and insulate the water tempera-ture sensor on the water supply line, and then connect theduct heater control contacts to the duct heater controlcircuit.

If night setback (U-terminal) is used, the duct heater willrespond to the occupied W1 thermostat signal. The loadshed input (L-terminal) cannot be used for other controlfunctions when being used with the BSK.

The BSK is a DC voltage device, when the BSK is used thethermostat must be wired for VDC operation, one example isprovided below. This example is for a 2-circuit WSHP, R1 isa field supplied 24vdc relay. R1 is not required on 1-circuitunits.

Wire ends to be FieldConnected to theMark IV/AC Board

WaterTemperature

Sensor

Signal toremote ductheatercontrol circuit

Auxiliary Relay

BoilerlessSystemBoard

No

rmal

Ove

rid

e

Orange

Yellow

White

Wire endsfrom Boilerless

System Kit


WSHP Mark IV/AC Board Low Voltage Terminal Strip WSHP Mark IV/AC Board Low Voltage Terminal Strip

Control Box

Boilerless System Kit

/ IM 439

The auxiliary relay is designed to interface external equipmentwith the Mark IV/AC board. The auxiliary relay has been pro-vided with the components necessary to protect from electricaldamage that may occur to the Mark IV/AC board when usingstandard off-the-self relays. The auxiliary relay can be used toprovide fault signals, unit operation signals, or to provide ameans for remote equipment to control the Mark IV/AC board.The orange, yellow, and white connections are short flying leadspre-attached to the board. The diagrams shown are someconnection examples.

Auxilliary Relay (P/N 03005073)


WSHP Mark IV/AC Board Low Voltage Terminal Strip WSHP Mark IV/AC Board Low Voltage Terminal Strip

Operation: In this examplethe auxiliary relay contactscan be used to indicate afault condition. With theauxiliary relay connectedas shown, the normallyopen contacts will closeduring a fault condition.

Operation: In this examplethe auxiliary relay contactscan be used to signalWSHP fan operation toanother device. In thisexample when thethermostat energizes the“G” terminal the auxiliaryrelay normally opencontacts will close.

Operation: In this examplethe auxiliary relay is usedto interface other controldevices to the Mark IV/ACboard. Using the Orange (-)and White (+) wires, and24vac or 24vdc, anotherdevice could be used tostart and stop the WSHPheating sequence.

IM 439 /

Field Installed Options of MicroTech 2000 Units

1st Control Signal Output 2nd Control Signal Output

3rd Control Signal Output 4th Control Signal Output

Terminal Boards(Located externally on the WSHP chassis)

Terminals Located onMicroTech 2000 Auxiliary Board

J6

24VACPilot Duty Relay

(by others)

Use contacts as needed for option


J7


(by others)



J10


(by others)



(by others)

MicroTech 2000 units can provide up to 4-outputs, that canbe configured for any of the following output control signals:

1) Scheduled OutputWhen using a Network Master Panel (NMP) these outputscan be assigned to one of 32 available schedules. Theoutput will energize when the assigned schedule is occu-pied and de-energize when in unoccupied. These outputscould be used to control lights, etc.

2) Auxiliary Heat (Skin Heat)When using a Loop Water Controller (LWC) the MicroTech2000 receives loop water temperature information fromthe LWC and will use the Auxiliary Heat output for heatingwhen loop water temperature is inappropriate for heatpump heating. These outputs provide a signal that can beused to control a remote electric heater. The output willenergize on a call for electric heat and de-energize whennot required.

3) Fresh Air DamperThese outputs provide a signal that can be used to controla remote fresh air damper. The output will energize whenthe unit fan is energized and de-energize when the unitfan is de-energized.

4) Motorized Water ValveThese outputs provide control for a motorized water valvethat can be used to stop or divert flow away from theWSHP when compressor operation is not needed. Theoutput will be energized when compressor operation isrequired.

If more than one of the above control signals is required ona single WSHP, the MicroTech 2000 Auxiliary board(073312701) must be used and these additional outputcontrol signals will be connected to the Auxiliary board. TheAuxiliary board is provided in all 2-circuit units. 1-circuit unitscan provide up to 4-outputs while 2-circuit units only have 3-outputs available. The 4th control signal output shown in thediagrams below is not available on 2-circuit units.

If the Auxiliary board is added in the field to provide additionaloutputs it will need to be mounted within the WSHP controlbox so that J1 on the Auxiliary board can be connected to J6on the MicroTech 2000 board without exceeding a maximumwire length of 10”.

Also, each output is by default configured to “none” andmust be field set to one of the four signal types listed aboveusing the Monitor software, cable, and a PC communicatingto the unit through an MCG panel.

/ IM 439

Troubleshooting

Should a major problem develop, check the status lights onthe MicroTech board or the Mark IV board(s) and refer to thefollowing information for possible cause and corrective steps:

Neither fan nor compressor run:1. The fuse may be blown or the circuit breaker is open.

Check electrical circuits and motor windings for shorts orgrounds. Investigate for possible overloading. Replacefuse or reset circuit breakers after fault is corrected.

2. Wires may be loose or broken. Replace or tighten.3. Supply voltage may be too low. Check it with the power

company.4. Control system may be faulty. Check thermostat for

correct wiring and check 24 volt transformer for burnout.

Fan operates but compressor does not:1. Wires may be loose or broken. Replace or tighten.2. The high pressure may have tripped due to:

a. Fouled or plugged condenser.b. Lack of or no condenser water.c. Too warm condenser water.d. Not enough airflow over the coil due to dirty filters.e. Coil or fan motor failure.

3. The low temperature switch may have tripped due to:a. Fouled or plugged condenser.b. Lack of or no condenser water.c. Too cold compressor water.d. Not enough airflow over the coil due to dirty filters.e. Coil or fan motor failure.

4. Check thermostat setting, calibration and wiring.5. The compressor overload protection is open. If the com-

pressor dome is extremely hot, the overload will not resetuntil cooled down. If the overload is external, replace it. Ifthe overload is internal, replace the compressor.

6. The internal winding of the compressor motor may begrounded to the compressor shell. If so, replace thecompressor.

7. The compressor winding may be open. Check continuitywith ohmmeter. If the winding is open, replace the com-pressor.

Compressor attempts to start but doesn’t:Check for defective compressor by making resistance checkon winding.

Compressor runs in short cycle:1. Check thermostat mounting and location.2. Check all relays, relaying and contacts.3. Check high pressure switch.4. Check low temperature switch.5. See if reversing valve has not fully shifted to either side.

Insufficient cooling or heating:1. Check thermostat for improper location.2. Airflow may be insufficient. Check and clean the filter.3. The reversing valve may be defective, creating a bypass

of refrigerant. If the unit will not heat, check the reversingvalve coil.

4. Check expansion valve(s) for possible restriction of refrig-erant flow.

5. Check for restriction in water flow.

Insufficient water flow through condenser:1. Check to see that valves are open all the way.2. Check for air in lines.3. Check circulating pump.

Water drips from conditioner:1. Check for plugged condensate drain.2. Check for dirty filter.3. Check to see if condensate drain runs uphill.4. See if blower motor is up to speed.5. Check for loose or mispositioned blower.6. Are drains properly trapped?

Noisy unit operation:1. Check for fan wheel hitting the housing. Adjust for clearance.2. Check for bent fan wheel. Replace if damaged.3. Check for loose fan wheel on shaft. Tighten.4. Make sure compressor is floating free on its isolator

mounts.5. Check for tubing touching compressor or other surface.6. Check screws on all panels. Tighten.7. Check for chattering or humming in the contactor relays

due to low voltage or a defective holding coil. Replacecomponent.

8. Check water balance to unit for proper water flow rate.

IM 439 /

Maintenance1. Normal maintenance on all conditioners is generally lim-

ited to filter changes and fan motor lubrication. Lubrica-tion of the fan motor should be performed in accordancewith the instruction label on the conditioner. Be sure touse non-detergent electric motor oil.

2. Filter changes are required at regular intervals. The timeperiod between changes will depend upon the projectrequirements. Some applications such as motels producea lot of lint from carpeting and linen changes, and willrequire more frequent filter changes. It is suggested thatthe filter be checked at 60-day intervals for the first yearuntil experience is acquired. If light cannot be seen throughthe filter when held up to sunlight or a bright light, it shouldbe changed. A more critical standard may be desirable.

3. The condensate drain pan should be checked annuallyand cleaned and flushed as required.

4. Recording of performance measurements of volts, amps,and water temperature differences (both heating andcooling) is recommended. A comparison of logged datawith start-up and other annual data is useful as an indica-tor of general equipment condition.

5. Periodic lockouts almost always are caused by air orwater problems. The lockout (shutdown) of the conditioneris a normal protective result. Check for dirt in the watersystem, water flow rates, water temperatures. If the lockoutoccurs in the morning following a return from night set-back, entering air below machine limits may be the cause.

AAF-McQuay Incorporated4900 Technology Park Boulevard, Auburn, NY 13201-9030 USA, (315) 253-2771

Printed on recycled paper containing at least 10% post-consumer material.©2000 AAF-McQuay Incorporated

IM 439-12 (Rev. 10/00)

large vertical water source heat pumps 6 thru 25 tons

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