Thermo King 098203, Maintenance Manual

Page: 161 / 264

Electrical Maintenance
159
The Low Pressure Cutout Switch or Suction Transducer will have the same function, since the unit only
has one fitting on the suction tube, the unit can have either a Low Pressure Cutout Switch or Suction
Transducer but not both.
The following procedure is to replace a Low Pressure Cutout Switch (LPCO) with a Suction Transducer.
To replace a Suction Transducer with a Low Pressure Cutout Switch follow instructions in reverse.
1. Remove LPCO switch from suction tube. Fitting on the suction tube has a Schrader valve in it,
unscrew the LPCO.
2. Disconnect the LPCO wires from J9 pins 5 and 6, remove switch and harness from unit.
3. Install a jumper wire on J9 pins 5 to 6.
4. Screw the Suction Transducer on the fitting on the suction tube.
5. Route wire harness into control box.
6. Connect wires to J1 pins 7, 8, 9.
a. White wire to pin 7.
b. Red wire to pin 8.
c. Black wire to pin 9.
7. Secure harness.
8. Start unit, press F4 to enter Menu. Press F3 to scroll down to CONFIGURATION, press F4 to enter,
Press F3 to scroll down to OPTIONS, press F4 to enter. Press F3 to scroll down to SUCTUION
PRESSURE OPTION, press F4 to enter. Press F2 to highlight SENSOR MOUNTED, press and hold
F4 to accept and to confirm change.
Alarm 31 LOW PRESS CUTOUT OOCL only, logged in the data logger
Alarm 120 SUCTION PRESSURE SENSOR ERROR output of sensor outside limits
Alarm 136 TRANSDUCER CIRCUIT ERROR detects no 12V output to sensor
Message 32 LOW PRESS CUTOUT- PLEASE WAIT Suction pressure < 5-11 in. vacuum
Message 33 LPCO TIMER HOLD – PLEASE WAIT Suction pressure > 4-7 psig with 30 second delay
If no LPCO or transducer is available for repair, add jumper wire for LPCO or configure transducer
NONE.
CAUTION: REPAIR WHEN PARTS ARE AVAIVALBE, DO NOT RUN WITHOUT LOW
PRESSURE PROTECTION.
Figure 135: Options Menu Figure 136: Suction Pressure Option