Trouble Shooting and Service Chart
COMPLAINT
POSSIBLE CAUSE
REPAIR
Unit operates
1. Shortage of refrigerant.
1. Fix leak, add charge.
F
long or
2. Control contacts stuck or frozen
2. Clean contacts or replace control.
continuously
closed.
3. Refrigerated or air conditioned space
3. Determine fault and correct.
has excessive lead or poor insulation.
4. system inadequate to handle load.
4. Replace with larger system.
5. Evaporator cell iced.
5. Defrost.
6. Restriction in refrigeration system.
6. Determine location and remove.
7. Dirty condenser.
7. Clean condenser.
8. Filter dirty.
8. Clean or replace.
Start capacitor
1. Relay contacts not operating properly.
1. Clean contacts or replace relay if
G
open, shorted,
necessary.
or blown.
2. Prolonged operation on start cycle due
to:
a. Low voltage to unit.
2a.
Determine reason and correct.
b. Improper relay.
2b.
Replace.
c. Starting load too high.
2c.
Correct by using pump down arrange-
ment if necessary.
3. Excessive short cycling.
3. Determine reason for short cycling (E
above) and correct.
4. Improper capacitor.
4. Determine correct size & replace.
Run capacitor
1. Improper capacitor.
1. Determine correct size and replace.
H
open, shorted,
2. Excessively high line voltage (100% of)
2. Determine reason and correct.
or blown
rated - max).
Relay defective
1. Incorrect relay.
1. Check and replace.
I
or burned out
2. Incorrect mounting angle.
2. Remount relay in correct position.
3. Line voltage too high or too low.
3. Determine reason and correct.
4. Excessive short cycling.
4. Determine reason (See E above) and
correct.
5. Relay being influenced by loose vibrat-
5. Remount rigidly.
ing mounting.
6. Incorrect run capacitor.
6. Replace with proper capacitor.
Space
1. Control setting too high.
1. Reset control.
J
temperature
2. Expansion valve too small.
2. Use larger valve.
too high
3. Cooling coils too small.
3. Add surface or replace.
4. Inadequate air circulation.
4. Improve air movement.
Suction line
1. Expansion valve passing excess refrig-
1. Readjust valve or replace with smaller
K
frosted or
erant or is oversized.
valve.
sweating
2. Expansion valve stuck open.
2. Clean valve of foreign particles, re-
place if necessary.
3. Evaporator fan not running.
3. Determine reason and correct.
4. Overcharge of refrigerant.
4. Correct charge.
Liquid line
1. Restriction in dehydrator or strainer.
1. Replace part.
L
frosted or
2. Liquid shut-off (king valve) partially
2. Open valve fully.
sweating
closed.
Unit noisy
1. Loose parts or mountings.
1. Find and tighten.
M
2. Tubing rattle.
2. Reform to be free of contact.
3. Bent fan blade causing vibration.
3. Replace blade.
4. Fan motor bearings worn.
4. Replace motor.
