Thermistor and PSIO Module Wiring
024-030 UNITS — Connect the thermistors and transducer
harness wires as follows:
1. Locate the 2 thermistors provided (See Fig. 1).
2. Mark both ends of one of the thermistors.
3. Run the lead end of both thermistors into the control
box through the field wiring opening on the right-hand
side of the control box and over to the accessory PSIO2
(See Fig. 5).
4. Connect the red and black leads from the marked ther-
mistor to PSIO2, plug J7-TOP, pins 2 and 3, respec-
tively. See Fig. 5.
5. Connect the red and black leads from the unmarked ther-
mistor to PSIO2, plug J7-TOP, pins 5 and 6, respec-
tively. See Fig. 5.
6. Locate the harness with the 6 wires in the control box
(the same harness used previously. Four of the wires
(brown, orange, white, and gray) are connected together
with a wire nut (See Fig. 2). Remove this wire nut from
the 4 wires, and strip each one back
1
⁄
2
inch.
7. Connect the brown wire to the white wire from PSIO1,
plug J7-TOP, pin 7, using the wire nut provided.
8. Connect the orange wire to the white wire from pin 10
of the same plug used in Step 7 using the wire nut
provided.
9. Connect the white wire to the white wire from pin 13 of
the same plug used in Step 7 using the wire nut
provided.
10. Connect the gray wire to the white wire from pin 16 of
the same plug used in Step 7 using the wire nut
provided.
11. Run the other ends of the 2 thermistors (probe ends) un-
derneath the baffle in the condenser section over to the
compressors with the marked thermistor going to com-
pressor no. 1. See Fig. 6 and 7.
034,044 UNITS — Connect the thermistors and transducer
harness wires as follows:
1. Locate the 2 thermistors and 4 transducer plug har-
nesses provided (see Fig. 1).
2. Mark both ends of one of the thermistors.
3. Mark each of the transducer plug harness white wires
with different marks so that they can be easily distin-
guished.
4. Run 2 of the transducer harnesses and the marked ther-
mistor lead ends up through the bottom left side of
the control box and over to the PSIO modules (See
Fig. 3).
5. Run the other 2 transducer harnesses and the unmarked
thermistor lead ends up through the bottom right side of
the control box and over to the PSIO modules.
6. Connect the red and black leads from the marked ther-
mistor to PSIO2, plug J7-TOP, pins 2 and 3.
7. Connect the red and black leads from the unmarked ther-
mistor to PSIO2, plug J7-TOP, pins 5 and 6.
8. Connect all 4 red wires from the transducer harnesses
(with a wire nut provided) to the other end of the red
wire that was connected to TB3 earlier. See Fig. 3.
LEGEND
C
— Contactor
CB
— Circuit Breaker
CCB
— Control Circuit Breaker
DPT
— Discharge Pressure Transducer
HIR
— Heat Interlock Relay
HR
— Heater Relay
IFC
— Indoor (Evaporator) Fan Contactor
MMC
— Head Pressure Control Device
PEC
— Power Exhaust Contactor
PSIO
— Processor Module
SGT
— Suction Gas Thermistor
SPT
— Suction Pressure Thermistor
TB
— Terminal Block
TRAN — Transformer
Fig. 5 — Thermistor and PSIO Wiring, 024-030 Units
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