Troubleshooting guide

OM 931-3 / Page 25 of 28
MicroTech III Unit Controller with PSC Motor, Desuperheater and I/O Expansion Module for Hot Gas Reheat
Control (Unit Sizes 019-070) 208/230/60/1-Phase
*Drawing No. 669007101A
Note: The gray tinted areas in the wiring diagram; Leaving Water (LWT), Discharge Air (DAT) and Return Air (RAT) Temperature
sensors are shipped or are eld installed on units congured with a communication module.
*Wiring diagrams are typical. For the latest drawing version refer to the wiring diagram located on the inside of the controls access
panel of the unit.
T
able B
208V
RED
230V
ORG
Legend
Item
Description
C1
Capacitor-Compressor
C2
Capacitor-Fan
CC
Compressor - Contactor
CM
Compressor - Motor
COS Condensate Overow Sensor
DA
T
Discharge Air Temp Sensor
EWT
Entering Water Temp Sensor
HP
High Pressure Switch
HTR
Electric Heater Cartridge
IOEXP
I/O Expansion Board / Harness
ISO-NC
Isolation V
alve - Normally Closed
ISO-NO
Isolation V
alve - Normally Open
DSHP
Desuperheater Pump
HGRH
3-W
ay Valve Solenoid
P1
24 V
AC Supply I/O Expansion Brd.
LED1
LED
Annunciator / Harness
LED2
LED
Annunciator / Harness
LP
Low Pressure Switch
SL
TS
Suction Line
Temp Sensor
LWT
Leaving W
ater Temp Sensor
MIII
MicroT
ech III Main Board
R1
Relay - Fan Motor
R2
Relay - Electric Heat
RA
T
Return
Air Temp Sensor
RV
Reversing V
alve Solenoid
TB1
Power
Terminal Block
X1
Primary 24 V
AC Transformer
X2
Secondary 24 V
AC Transformer
_____
Standard Unit Wiring
_ _ _ _
Optional Wiring (by others)
Notes:
1.
Main Board Jumpers:
JP3 Geothermal.
2.
I/O Expansion Board Jumpers:
JP4 Hot Gas Reheat.
JP3 Supplemental EH.
JP4 Boilerless EH.
JP5 2-Speed Fan
T
ransformer:
Unused wire to be capped.