FORM 195.26-NM3
YORK INTERNATIONAL
77
TROUBLESHOOTING CHART
PROBLEM
CAUSE
SOLUTION
No display on panel
1. No 115VAC to 2T.
1. Checking wiring and fuses (1 FU and 2 FU).
Unit will no operate
Check emergency stop contacts
5
to
1
.
2. No 24VAC to Power Supply Board.
2. Check wiring 2T to Power Supply Board.
3. 2T defective, no 24VAC output.
3. Replace 2T.
4. No +12V output from Power Supply Board.
4. Replace Power Supply Board or isolate exces-
sive load on the board.
Contact YORK Service Before Replacing Circuit Boards!
“NO RUN PERM”
1. Remote cycling device open.
1. Check cycling devices and thermostat connected
to terminals 13 & 14 and 13 & 15 of the TB3
Terminal Block.
2. “System” switch in the OFF position.
2. Place switches to the ON position.
CONTACTOR DOES NOT ENERGIZE
1. External high pressure switch tripped.
1. Check external high pressure switch, fan
operation, and discharge pressure stored in
memory. Air flow from fans must be up.
2. External motor protector tripped.
2. Check for defective External motor protector,
wiring and motor problems. Assure that motor
protector is not tripped due to external high
pressure switch.
3. Defective relay output board.
3. Replace relay output board.
CONTACTOR ENERGIZES
1. Improper system high voltage.
1. Check system high voltage supply.
2. Defective contactor contact and contactor.
2. Check contacts and contactor.
3. Faulty high voltage wiring.
3. Check wiring.
4. High motor current stored in memory.
4. Loose calibration resistors in J9 (SYS 1) OR
J10 (SYS 2) of power supply board.
5. Defective current transformer (CT).
5. CT resistance 42-44
Ω.
“LOW OIL PRESS”
1. Low oil charge.
1. Oil level should be visible in either sight glass at
Fault
all times. Add YORK “C” oil if necessary.
2. Too much refrigerant-in oil, particularly
2. Check crankcase oil heater operation. (350 Watt
on start-up.
heater should be “ON” when unit is “OFF”.
Measure heater current. (Should be min. 2 amps.)
3. Liquid Line Solenoid Valve (LLSV) not
3. Check wiring and LLSV.
operating.
4. Suction Pressure Transducer or wiring
4. Compare display to a gauge (SYS OFF).
defective.
Replace defective component.
5. Oil Pressure Transducer or wiring
5. Compare suction and oil gauges to display.
defective.
Replace defective component.
“LOW SUCTION”
1. Improper Suction Pressure Cut-out
1. Adjust per recommended settings and restart
Fault
adjustment.
unit.
2. Low refrigerant charge.
2. Repair leak/add refrigerant.
3. Fouled filter drier.
3. Change drier core.
4. Thermal expansion valve adjustment/failure.
4. Adjust compressor suction superheat to 15°F.
or replace power element (or valve).
5. Piping problems.
5. Check piping / design.
6. Defective suction pressure transducer.
6. Replace transducer.
7. Faulty wiring to transducer.
7. Check wiring.
8. Check piping design
8. Modify piping design.
“MOTOR CURRENT”
Fault
Motor Contactor may
or may not Energize
Contact YORK Service Before Replacing Circuit Boards!
