Bryant 548F User Manual
Page 42
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42
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TROUBLESHOOTING
Table 30 — Heating and Cooling Troubleshooting
PROBLEM
CAUSE
REMEDY
Compressor and
outdoor fan
will not start.
Power failure.
Call power company.
Fuse blown or circuit breaker tripped.
Replace fuse or reset circuit breaker.
Defective thermostat, contactor, transformer,
control relay, or capacitor.
Replace component.
Insufficient line voltage.
Determine cause and correct.
Incorrect or faulty wiring.
Check wiring diagram and rewire correctly.
Thermostat setting too high.
Lower thermostat setting below room temperature.
High pressure switch tripped.
See problem ‘‘Excessive head pressure.’’
Low pressure switch tripped.
Check system for leaks. Repair as necessary.
Freeze-up protection thermostat tripped.
See problem ‘‘Suction pressure too low.’’
Compressor will not
start but outdoor
fan runs.
Faulty wiring or loose connections in compres-
sor circuit.
Check wiring and repair or replace.
Compressor motor burned out, seized, or
internal overload open.
Determine cause. Replace compressor.
Defective run/start capacitor, overload, start
relay.
Determine cause and replace.
One leg of 3-phase power dead.
Replace fuse or reset circuit breaker. Determine cause.
Compressor cycles
(other than normally
satisfying thermostat).
Refrigerant overcharge or undercharge.
Recover refrigerant, evacuate system, and recharge to nameplate.
Defective compressor.
Replace and determine cause.
Insufficient line voltage.
Determine cause and correct.
Blocked outdoor coil or dirty air filter.
Determine cause and correct.
Defective run/start capacitor, overload, or start
relay.
Determine cause and replace.
Defective thermostat.
Replace thermostat.
Faulty outdoor-fan (cooling) or indoor-fan
(heating) motor or capacitor.
Replace.
Restriction in refrigerant system.
Locate restriction and remove.
Compressor operates
continuously.
Dirty air filter.
Replace filter.
Unit undersized for load.
Decrease load or increase unit size.
Thermostat set too low.
Reset thermostat.
Low refrigerant charge.
Locate leak; repair and recharge.
Leaking valves in compressor.
Replace compressor.
Air in system.
Recover refrigerant, evacuate system, and recharge.
Outdoor coil dirty or restricted.
Clean coil or remove restriction.
Compressor makes
excessive noise.
(Sizes 048, 060 and
072 only)
Compressor rotating in the wrong direction.
Reverse the 3-phase power leads as described in
Start-Up, page 37.
Excessive head
pressure.
Dirty air filter.
Replace filter.
Dirty outdoor coil.
Clean coil.
Refrigerant overcharged.
Recover excess refrigerant.
Air in system.
Recover refrigerant, evacuate system, and recharge.
Condensing air restricted or air short-cycling.
Determine cause and correct.
Head pressure
too low.
Low refrigerant charge.
Check for leaks; repair and recharge.
Compressor valves leaking.
Replace compressor.
Restriction in liquid tube.
Remove restriction.
Compressor rotating in the wrong direction
(unit sizes 048, 060 and 072)
Reverse the 3-phase power leads as described in Start-Up, page 37.
Excessive suction
pressure.
High heat load.
Check for source and eliminate.
Compressor valves leaking.
Replace compressor.
Refrigerant overcharged.
Recover excess refrigerant.
Suction pressure
too low.
Dirty air filter (cooling) or dirty outdoor coil
(heating).
Replace filter.
Low refrigerant charge.
Check for leaks; repair and recharge.
Metering device or low side restricted.
Remove source of restriction.
Insufficient indoor airflow (cooling mode).
Increase air quantity. Check filter and replace if necessary.
Temperature too low in conditioned area.
Reset thermostat.
Field-installed filter drier restricted.
Replace.
Outdoor ambient below 25 F.
Install low-ambient kit.