JOHNSON CONTROLS
152
FORM 150.66-NM2
ISSUE DATE: 09/25/2020
SECTION 9 - SERVICE AND TROUBlEShOOTING
TROUBLESHOOTING
TABLE 30 – TROUBLESHOOTING
PROBlEM
CAUSE
SOlUTION
NO DISPLAY ON PANEL.
1. No 115VAC to 24 VAC
1a. Check wiring and fuse
UNIT WILL NOT OPERATE.
Transformer IT
1FU
b. Check wiring emergency
stop contacts 5 to l of TB1
Terminal
Block.
c. Replace 1T
2. No 24VAC to Microboard
2. Check wiring 1T to
Microboard.
3. Control Transformer IT defective, 3. Replace 1T
no 24VAC output.
4. Short in wire to temp. sensors
4. Unplug connections at
or pressure transducers.
Microboard to isolate.
5. Defective IPU & I/O board
5. Replace Microboard.
or Display board.
Contact YORK
Service before
Replacing circuit
Boards!
“FLOW SWITCH/REM
1. No chilled liquid flow.
1. Check chilled liquid flow.
STOP NO RUN PERMISSIVE”
2. Flow switch improperly
2. Check that the flow switch
installed.
is installed according to
manufacturer’s
instructions.
3. Defective flow switch.
3. Replace flow switch.
4. Remote cycling device open.
4. Check cycling devices
connected to terminals
13 and 14 of the CTB1
Terminal
Block.
“LOW SUCTION PRESSURE”
1. Improper suction pressure
1. Adjust per recommended
FAULT
cutouts
adjustments.
settings.
2. low refrigerant charge.
2. Repair leak if necessary
and add refrigerant.
3. Fouled filter dryer.
3. Change dryer/core.
CONT’D
Summary of Contents for YCAL0012EC
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