TC250D Universal Single Point PI Temperature Controller

The TC250D is a universal, single point temperature controller. It is a direct replacement for the TA239W, adding modern micro processor control functions and a clear LED readout. The TC250D uses the same sensor as the TA239W.The TC250D can be used in any heating or cooling system within the range of 40 to 205 oF (5-96 oC). It is designed to handle fast control loops with fluctuating loads, such as domestic hot water control, using our 15 second VM800 actuator and a 2- or 3-way control valve. It works equally well in slow systems using actuators with long run times.

Features• Very easy to use• Works with fast and slow control loops• PI control algorithm • Low load dead zone with adjustable activation point• High temperature alarm function• Fast sample rate of sensor input• Reversible output for heating or cooling applications• Works with any modulating valve or damper actuator

or variable speed drive • Option: Enclosure TC250D-EN with Mounting Plate TC250D-PL.

Technical DataPart number TC250DPower supply * 15 - 30 VdcPower consumption 75 mASensors (see page 4) Thermistor NTC 1.8 K ohmSensor sample rate 10 / sec.Analog output (AO) 0-10 or 2-10 VdcAlarm Relay SPDT 120 Vac 3 A max.If sensor input is open or shorted: DA: Output goes to 10 Vdc RA: Output goes to 0 VdcEnclosure size 6” (W), 6” (H), 3.5” (D)TCA-24 Optional power supply 120 Vac - 24 Vdc 1A. */ When used with the VM800, the controller is pow-ered by 16 Vdc from the actuator. For other actuators, use the optional 120 Vac - 24 Vdc power supply.

With the simple 3 button interface, select temperature scale and change control parameters to match system requirements. The factory defaults shown are for a fast system with fluctuating load.

Display Functions & Adjustments Default

F C Temperature scale oF or oC oF

100F Setpoint 40 - 205 oF (5 - 96 oC) 100 oF

p 50 P-band 9 - 360 oF (5 - 200 oC) 50 oF

i12 I-Time OFF or 1 - 480 seconds 12 s

HL 9 Dead zone activation point 0 - 10 Vdc 9 Vdc

DZ 9 Dead zone 4 - 12 oF (2 - 9 oC) 5 oF

0-10 2-10 Analog output 0 - 10 or 2 - 10 Vdc 0-10 Vdc

DR rR Direct or reverse acting output Dir. Acting

T 30 Actuator run time 15, 30, 60, 120, 180 30 sec

L 20 Limit, OFF or 15-40 oF over setpoint OFF

LT 3 Limit time delay 0.5 -10 minutes 3 min.

HL A High temperature limit alarm (blinking)

sE Sensor Error (open or shorted sensor)

def Reset to default values Yes or No

TC250D Wiring Terminals

Pow

er 1

5-30

Vdc

0/2

- 10

Vdc

outp

ut

Sens

or

Neu

tral

1 2 4 5 6 7 8 9

Com NC NOAlarm Relay

The TC250D is a proportional integral (PI) controller with an adjustable dead zone feature. The P action gives stability to the control loop but results in a higher or lower temperature than the desired setpoint. The integral action (I) corrects the size and duration of the P inaccuracy.The adjustable dead zone, 4-12 oF allows for very stable control at low loads (high control signal). The activation point for the dead zone can be set between 0-10 V (default = 9 V). At high load, there is a fixed dead zone (hysteresis) of 0.7 oF.The dead zone is used mostly in systems with large fluctua-tions in load, such as in control of domestic hot water. In slow systems with a stable load, and where a dead zone is not needed, set the activation point to 10 V. The use of a dead zone reduces the wear on the actuator in systems with large fluctuations in load and with long periods at low load.

Domestic Hot Water Control using a fast VM800 actuator & STP120-70 immersion sensor.Display FunctionF Temperature scale oF

100F Setpoint 100 oF

p 50 P-band 50 oF

i12 I-Time 12 s

HL 9 Dead zone activation point 9 V

DZ 5 Dead zone 5 oF

0-10 Analog output 0-10 Vdc

DR Direct acting output

T 30 Actuator run time 30 s

L 20 Temperature limit at 20 oF above setpoint

Lt 3 Limit delay 3 minutes.

Hot Water Heating Application using a slow actuator. Display FunctionF Temperature scale oF

160F Setpoint 160 oF

p120 P-band 120 oF

i90 I-Time 90 s

HL10 Dead zone activation point 10 V (inactive)

DZ Function not used when HL = 10 V

2-10 Analog output 2-10 Vdc

DR Direct acting output

T180 Actuator run time 180 s

LOFF High temperature limit OFF

If VM659 or VM92P actuators are used in this application, set the run time to 60 seconds.

System examples and initial parameter settings

2

Dead Zone(4-12 oF)

low load

high load

oF

hys. 0.7

low load (control signal)0% (10 V) 100%

(0/2 V)

HL = dead zone activation point 10 - 0 V

HL

Operator InterfaceThe simple 3 key operator interface performs all the functions needed to adjust and set the operating parameters for the control loop.

Press and hold the enter key for 3 seconds to place the interface in adjust mode.

Use the keys to move between functions.

Select a function with and then make changes with

When finished, confirm the change with then select the next function withthe up or down arrow key and make that adjustment.

When all changes have been made, hold down for 3 seconds to exit adjust mode.

Alarm Reset: Press down both keys for one second to reset a high limit alarm.

Note: If the alarm function is not used, increase the limit temperature (L) one step beyond maximimum, to OFF.

WARNING !A tempering system using the TC250D controller is not a safety control system. A separate solenoid valve must be installed for complete shutdown in case of too high water temperature.

3

Installation of controller: The TC250D housing has four tabs, one at each corner. Hold down the two upper or lower tabs and carefully pry off the lid. Use four #6 sheet metal screws to attach the controller to a wall or back plate. Enter wires through the bottom grommets. Verify polarity before connecting the DC voltage to terminals 1 & 2. Finish the wiring and snap the lid back in place.Option: NEMA 4 Enclosure TC250D-EN with Mounting Plate.

Wiring for VM1500E & VM5000E actuators

Sensor

SN neutralSP

1 3 X

Y

VM1500E / VM5000Eterminals

0/2 - 10 Vdc

24 V

dc p

ower

neutral

24 Vac

+-

TCA-24 120 Vac - 24 Vdcoptional power supply

40 VA Transformer supplied by installer

Always verify the +/- leads

1 2 4 5 6 7 8 9

Relay

High Limit Shutdown & Alarm Function (Works in D. A. mode only). Function is OFF by default (LOFF in Display)This is a high limit function that is activated if the temperature goes above setpoint by an adjustable number of degrees, for a certain length of time. This is set with L (temperature) and Lt (time). L is the number of degrees over setpoint and Lt is the delay in minutes before the function is activated. Example: Setpoint = 115oF, L = 15oF, Lt = 3 minutes. The alarm is triggered at 130oF after 3 minutes.The output for this function is a SPDT relay that can be wired to a N.C. solenoid valve and/or a remote alarm unit.Alarm Reset: Press down both keys for one second to reset a high temperature alarm.

Note: If the alarm function is not used, increase the limit temperature (L) one step beyond maximimum, to OFF.

Wiring for VM400, VM800, VM1500 actuators

Sensor STP120-70

H GG G0

D2 VCD1 VHC MXAI X1AO Y

markings on circuit boardmarkings on label

G1

VM400, VM800, VM1500 terminals

0/2 - 10 Vdc

16 Vdc power from actuator

neut

ral

24 Vac from transformer

Min. 25 VA Transformer supplied by installer

+-1 2 4 5 6 7 8 9

Relay

7 8 9

Com

Relay wiring

NCNO

1/2"

3”

Ø 1/8”

2.5”

x 2

.5”

1.25”

1 2

Sensor Wiring

STP120-70 fast immersion sensor. Stainless steel probe. Re-action time = 1.5 sec. Connection 1/2” NPS. No well needed. Use for domestic hot water and other fast control loops. Thermistor NTC 1.8 K

TS-ETS100 surface mounted pipe sensor.Thermistor NTC 1.8K

TS-ETD100-6 Duct sensor Lengths: 6” (other lengths avaiable).Thermistor NTC 1.8K

Optional NEMA 4 enclosure TC250D-EN, with mounting plate for TC250D.

TS-STX140 Slab / Ground sensorFour thermistors NTC 1.8K are placed equal distance over the 6 ft length of the 3/8” polythene tube.Comes with 6 ft connecting cable.When used in the ground, place the sensor portion inside a 1/2” pipe.

4

TCA-24 Optional power supply 120 Vac - 24 Vdc 1A. 6 ft cord. Use with all actuators except VM400, VM800 & VM1500. Verify polarity before connecting to controller.

Wiring for VM659 actuator

Sensor

0/2 - 10 Vdc (black)24 V

dc p

ower

neutral (blue)

+-

24 Vdc + (brown)

The VM659 comes with a 5 ft 3-wire cable

TCA-24 120 Vac - 24 Vdcoptional power supply

Always verify the +/- leads

VM659

1 2 4 5 6 7 8 9

Relay