Bryant 548D installation instructions Heating and Cooling Troubleshooting

TROUBLESHOOTING

Refer to Tables 14-16 and Fig. 46 for troubleshooting information.

Table 14 — Heating and Cooling Troubleshooting

PROBLEM	CAUSE	REMEDY
Compressor and	Power failure.	Call power company.
outdoor fan
	Fuse blown or circuit breaker tripped.	Replace fuse or reset circuit breaker.
will not start.
	Defective thermostat, contactor, transformer, or control relay.	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 for leaks, repair, and recharge.
	Freeze-up protection thermostat tripped.	See problem ‘‘Suction pressure too low.’’
Compressor will not start	Faulty wiring or loose connections in compressor circuit.	Check wiring and repair or replace.
but outdoor fan runs.	Compressor motor burned out, seized, or internal	Determine cause. Replace compressor.
	overload open.
	Defective overload.	Determine cause and replace.
	One leg of 3-phase power dead.	Replace fuse or reset circuit breaker.
		Determine cause.
Compressor cycles	Refrigerant overcharge or undercharge.	Recover refrigerant, evacuate system, and
(other than normally		recharge to nameplate.
satisfying thermostat).	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 overload.	Determine cause and replace.
	Defective thermostat.	Replace thermostat.
	Faulty outdoor-fan (cooling) or indoor-fan (heating) motor or	Replace.
	capacitor.
	Restriction in refrigerant system.	Locate restriction and remove.
Compressor operates	Dirty air filter.	Replace filter.
continuously.	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.
Scroll compressor	Compressor rotating in the wrong direction.	Reverse the 3-phase power leads as described in
makes excessive noise.		Start-Up, page 28.
Excessive head	Dirty air filter.	Replace filter.
pressure
	Dirty outdoor coil.	Clean coil.
	Refrigerant overcharged.	Remove excess refrigerant.
	Air in system.	Recover refrigerant, evacuate system, and
		recharge.
	Condensing air restricted or air short-cycling.	Determine cause and correct.
Head pressure	Low refrigerant charge.	Check for leaks, repair, and recharge.
too low.
	Compressor valves leaking.	Replace compressor.
	Restriction in liquid tube.	Remove restriction.
Excessive suction	High heat load.	Check for source and eliminate.
pressure.
	Compressor valves leaking.	Replace compressor.
	Refrigerant overcharged.	Recover excess refrigerant.
Suction pressure	Dirty air filter (cooling) or dirty outdoor coil (heating).	Replace filter or clean coil.
too low.
	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 temperature below 25 F.	Install low-ambient kit.
Compressor no. 2	Unit in economizer mode.	Proper operation; no remedy necessary.
will not run.

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