FORM NO.: 6U5M-A11M-NB-EN
JOHNSON CONTROLS 50
TROUBLE SHOOTING
TABLE 20 - TROUBLESHOOTING
No display on wire
controller.
Unit will not operate.
1. No power from microboard to 12VDC
wire controller.
2. No 230VAC to microboard.
3. Communication wire detective between
wire controller to unit.
1. Check microboard power supply and
the corresponding wiring.
2. Check power supply to microboard and
the corresponding wiring.
3. Check communication wiring.
Contact YORK Service
before replacing circuit
boards!
“Chiller Water Flow”
Fault
1.
No chilled liquid flow.
2.
Too much air in piping system.
3.
Flow switch improperly installed.
4.
Defective flow switch.
1.
Check chilled liquid flow.
2.
Purge the air though a release valve.
3.
Check that the flow switch is installed
according to manufacturer’s instructions.
4.
Replace flow switch.
“Low Suction Pressure”
Fault
1. Low refrigerant charge.
2. Fouled or clogged BPHE.
3. EEV defective.
4. Reduced flow of chilled.
5. Defective suction pressure
transducer/low pressure switch or
wiring.
6. Fans not operating (in heating mode).
1. Repair leak if necessary and add
refrigerant.
2. Clean BPHE.
3. Check the wiring, or replace EEV.
4. Check liquid flow rate. Check operation of
pump, clean pump strainer, purge chilled
liquid system of air.
5. Replace transducer/low pressure switch or
faulty wiring.
6. Check fan wiring and communication.
“High Discharge Pressure or
Compressor Overload” Fault
1. Condenser fans not operating or
operating backwards.
2. Too much refrigerant.
3. Air in refrigerant system.
4. Defective discharge pressure switch.
5. Compressor motor locked.
6. Compressor internal motor protector
(MP) open.
1. Check fan motor. Assure fan blows air
frontward.
2. Remove refrigerant.
3. Evacuate and recharge system.
4. Replace discharge pressure switch.
5. Replace compressor.
6. Verify refrigerant charge is not low.
Verify superheat setting (3-5°C).
Verify correct compressor rotation.
Verify compressor is not over loaded.
Cooke Industries - Phone: +64 9 579 2185 Email: sales@cookeindustries.co.nz Web: www.cookeindustries.co.nz
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