Troubleshooting; Table 26 - Troubleshooting - York YCWL0056SE Installation Operation & Maintenance

FORM 201.26-NM1
ISSUE DATE: 1/19/2018

TABLE 26 - TROUBLESHOOTING

PROBLEM
NO DISPLAY ON PANEL
UNIT WILL NOT OPERATE
FLOW SWITCH/REM
STOP NO RUN PERMISSIVE
LOW SUCTION PRESSURE FAULT
JOHNSON CONTROLS

TROUBLESHOOTING

CAUSE
1. No 115VAC to 24 VAC Transformer.
2. No 24VAC to Microboard.
3. Control Transformer defective, no
24VAC output.
4. Short in wire to temp. sensors or pres-
sure transducers.
5. Defective IPU II & I/O board or Display
board.
1. No chilled liquid flow.
2. Flow switch improperly installed.
3. Defective flow switch.
4. Remote cycling device open.
1. Improper suction pressure cutout
adjustments.
2. Low refrigerant charge.
3. Fouled filter dryer.
4. TXV defective.
5. Reduced flow of chilled liquid through
the cooler.
6. Defective suction pressure transducer/
low pressure switch or wiring.
7. LLSV defective.
SECTION 9 – SERVICE AND TROUBLESHOOTING
SOLUTION
1a. Check wiring and fuse 1FU.
1b. Check wiring emergency stop
contacts 5 to L of TB1 terminal
block.
1c. Replace Control Transformer
2. Check wiring Control Transform-
er to Microboard.
3. Replace Control Transformer.
4. Unplug connections at IPU II &
IO board to isolate.
5. Replace IPU II & IO board or the
Display Board.
Contact Johnson
Controls Service
before replacing
circuit boards.
1. Check chilled liquid flow.
2. Check that the flow switch is
installed according to manufac-
turer's instructions.
3. Replace flow switch.
4. Check cycling devices connect-
ed to terminals 13 and 14 of the
CTB1 terminal block.
1. Adjust per recommended set-
tings.
2. Repair leak if necessary and add
refrigerant.
3. Change dryer/core.
4. Replace TXV.
5. Check GPM (See Limitations in
SECTION 4 - INSTALLATION).
Check operation of pump, clean
pump strainer, purge chilled
liquid system of air.
6. Replace transducer/low pressure
switch or faulty wiring. Refer to
Service section for pressure /
voltage formula.
7. Replace LLSV.
9
165