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PROBLEM
COMPRESSOR DOES NOT RUN
Contactor Open
1. Power off.
2. Fuses blown in field power circuit.
3. Alarm tripped.
4. No control power.
5. Compressor circuit breaker tripped.
6. Safety device lockout circuit active.
7. Low-pressure switch open.
8. High-pressure switch open.
9. Loose electrical connections.
10. Compressor stuck.
Contactor Closed
1. Compressor leads loose.
2. Motor windings open.
3. Single phasing.
COMPRESSOR STOPS ON HIGH-PRESSURE SWITCH
Outdoor Fan On
1. High-pressure switch faulty.
2. Airflow restricted.
3. Air recirculating.
4. Noncondensables in system.
5. Refrigerant overcharge.
6. Line voltage incorrect.
7. Refrigerant system restrictions.
Outdoor Fan Off
1. Fan slips on shaft.
2. Motor not running.
3. Motor bearings stuck.
4. Motor overload open.
5. Motor burned out.
COMPRESSOR CYCLES ON LOW-PRESSURE SWITCH
Indoor-Air Fan Running
1. Filter drier plugged.
2. Expansion valve power head defective.
3. Low refrigerant charge.
Airflow Restricted
1. Coil iced up.
2. Coil dirty.
3. Air filters dirty.
4. Dampers closed.
Indoor-Air Fan Stopped
1. Electrical connections loose.
2. Fan relay defective.
3. Motor overload open.
4. Motor defective.
5. Fan belt broken or slipping.
LEGEND
HSIO — Human Sensory Input/Output Device
DSIO — Processor Module
VFD
— Variable Frequency Drive
TROUBLESHOOTING AND DIAGNOSTICS
1. Restore power.
2. After finding cause and correcting, replace with correct size fuse.
3. Check alarm history on HSIO.
4. Check secondary fuse(s); replace with correct type and size. Re-
5. Check for excessive compressor current draw. Reset breaker; re-
6. Reset lockout circuit at HSIO or circuit breaker.
7. Check for refrigerant undercharge, obstruction of indoor airflow, or
8. Check for refrigerant overcharge, obstruction of outdoor airflow, air in
9. Tighten all connections.
10. See 06E compressor service literature.
1. Check connections.
2. See 06E compressor service literature.
3. Check for blown fuse. Check for loose connection at
1. Replace switch.
2. Remove obstruction.
3. Clear airflow area.
4. Purge and recharge as required.
5. Purge as required.
6. Consult power company.
7. Check or replace filter drier, expansion valve, etc. Check that com-
1. Tighten fan hub setscrews.
2. Check power and capacitor.
3. Replace bearings.
4. Check overload rating. Check for fan blade obstruction.
5. Replace motor.
1. Replace filter drier.
2. Replace power head.
3. Add charge. Check low-pressure switch setting.
1. Check refrigerant charge.
2. Clean coil fins.
3. Clean or replace filters.
4. Check damper operation and position.
1. Tighten all connections.
2. Replace relay.
3. Power supply.
4. Replace motor.
5. Replace or tighten belt.
56
SOLUTION
place transformer if primary windings receiving power.
place if defective.
whether compressor suction shutoff valve is fully open. Make sure
liquid line solenoid valve(s) is open.
system or whether compressor discharge valve is fully open. Be sure
outdoor fans are operating correctly.
compressor terminal.
pressor discharge valve is fully open.
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