Bryant 576b installation instructions Troubleshooting Guide

TROUBLESHOOTING GUIDE

SYMPTOM	CAUSE	REMEDY
Compressor does not run —	Power off.	Restore power.
Contactor open
	Fuses blown.	Replace with correct fuses after finding cause
		and correcting.
	Transformer open/shorted.	Replace transformer if primary windings are
		receiving power and no output.
	Thermostat circuit open.	Check thermostat setting.
	Low-pressure switch open.	Check for refrigerant undercharge or system
		leak.
	High-pressure switch open.	Check for refrigerant over charge or
		obstruction of outdoor airflow.
	Connections loose.	Tighten all connections.
	Compressor motor thermostat open.	Check for excessive motor temperature.
Compressor does not run —	Compressor leads loose, broken.	Check connections with power off.
Contactor closed
	Single phasing.	Replace blown fuse.
	Compressor internal overload open.	Allow compressor motor windings to cool down to reset
		overload. Determine cause for overload opening.
Compressor cycles on high-	High-pressure switch faulty.	Replace switch.
pressure switch —
	Airflow restricted. Dirty coil.	Remove obstruction, clean condenser coil.
Condenser fan on
	Air recirculating.	Clear airflow area.
		Recover, evacuate and recharge as required. Refer to
	Noncondensables in system.	Carrier GTAC-II, Module 5, Charging, Recovery,
		Recycling, and Reclamation.
	Refrigerant overcharge.	Recover as required.
	Refrigerant system restrictions.	Check or replace filter drier, expansion
		valve, etc.
Compressor cycles on high-	Fan slips on shaft.	Tighten fan hub screws.
pressure switch —
	Motor not running.	Check power and capacitor 1/	3	and	3/ hp motor.
Condenser fan off					4
	Motor bearings seized.	Replace motor.
	Motor overload open.	Check overload rating. Check for fan blade obstruction.
	Motor burned out, windings open.	Replace motor.
Compressor cycles on low-	Filter drier plugged.	Replace filter drier.
pressure switch —
	Expansion valve power head	Replace power head.
Evaporator fan running
	defective.
	Low refrigerant charge.	Find leak, repair, evacuate system, and recharge.
	Expansion valve restricted/plugged.	Remove and replace expansion valve.
Airflow restricted —	Evaporator coil iced up.	Check refrigerant charge.
Low suction pressure
	Evaporator coil dirty.	Clean coil fins.
	Indoor-air filter dirty.	Clean or replace filters.
	Indoor-air dampers closed.	Check damper operation and position.
Indoor (evaporator) fan stopped —	Electrical connections loose.	Tighten all connections.
Low suction pressure
	Fan relay defective.	Replace relay.
	Motor overload open.	Check power supply.
	Motor defective.	Replace motor.
	Fan belt broken or slipping.	Replace or tighten belt.
Compressor runs but	Refrigerant charge low.	Add charge.
cooling insufficient —
	Head pressure low.	Check refrigerant charge.
Suction pressure low
	Indoor-air filters dirty.	Clean or replace filters.
	Expansion valve power head	Replace power head.
	defective.
	Expansion valve restricted/plugged.	Remove and replace expansion valve.
	Evaporator coil partially iced.	Check low-pressure setting.
	Evaporator airflow restricted.	Remove obstruction.
Compressor runs but
cooling insufficient —	Heat load excessive.	Check for open doors or windows.
Suction pressure high

NOTE: See Fig. 15 and 16 for component arrangements.

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