Bryant 581B Troubleshooting, LED Error Code Service Analysis, Heating Service Analysis

TROUBLESHOOTING

Table 18 Ð LED Error Code Service Analysis

PROBLEM	CAUSE	REMEDY
Hardware failure.	Loss of power to IGC.	Check 5-amp fuse on IGC, power to unit, 24-v circuit breaker, and
(LED Off)		transformer. Units without a 24-v circuit breaker have an internal over-
		load in the 24-v transformer. If the overload trips, allow 10 minutes for
		automatic reset.
Limit switch fault.	High-temperature limit switch	Check the operation of the indoor (evaporator) fan motor. Ensure that
(LED 2 Flashes)	is open.	the supply-air temperature rise is in accordance with the range on the
		unit nameplate.
Flame sense fault.	The IGC sensed ¯ame that	Reset unit. If problem persists, replace control board.
(LED 3 Flashes)	should not be present.
4 consecutive limit switch trips.	Inadequate air¯ow to unit.	Check operation of indoor (evaporator) fan motor and that supply-air
(LED 4 Flashes)		temperature rise agrees with range on unit nameplate information.
Ignition lockout.	Unit unsuccessfully attempted	Check ignitor and ¯ame sense electrode spacing, gas, etc. Ensure that
(LED 5 Flashes)	ignition for 15 minutes.	¯ame sense and ignition wires are properly terminated. Verify that unit
		is obtaining proper amount of gas.
Induced-draft motor fault.	IGC does not sense that	Check for proper voltage. If motor is operating, check the speed sensor
(LED 6 Flashes)	induced-draft motor is operating.	plug/IGC Terminal J2 connection. Proper connection: PIN 1-White,
		PIN 2-Red, PIN 3-Black.
Rollout switch fault.	Rollout switch has opened.	Rollout switch will automatically reset, but IGC will continue to lock out
(LED 7 Flashes)		unit. Check gas valve operation. Ensure that induced-draft blower
		wheel is properly secured to motor shaft. Reset unit at unit disconnect.
Internal control fault.	Microprocessor has sensed an	If error code is not cleared by resetting unit power, replace the IGC.
(LED 8 Flashes)	error in the software or hardware.

LEGEND

IGC Ð Integrated Gas Unit Controller

LED Ð Light-Emitting Diode

WARNING: If the IGC must be replaced, be sure to ground yourself to dissipate any electrical charge that may be present before handling new control board. The IGC is sensitive to static electricity and may be damaged if the necessary precautions are not taken.

IMPORTANT: Refer to Table 19 Ð Heating Service Analysis for ad- ditional troubleshooting analysis.

Table 19 Ð Heating Service Analysis

PROBLEM	CAUSE	REMEDY
Burners will not	Misaligned spark electrodes.	Check ¯ame ignition and sensor electrode positioning. Adjust as needed.
ignite.	No gas at main burners.	Check gas line for air, purge as necessary. After purging gas line of air, allow gas
		to dissipate for at least 5 minutes before attempting to relight unit.
		Check gas valve.
	Water in gas line.	Drain water and install drip leg to trap water.
	No power to furnace.	Check power supply, fuses, wiring, and circuit breaker.
	No 24 v power supply to	Check transformer. Transformers with internal overcurrent protection require a cool
	control circuit.	down period before resetting. Check 24-v circuit breaker, reset as necessary.
	Miswired or loose connections.	Check all wiring and wirenut connections.
	Burned-out heat anticipator in	Replace thermostat.
	thermostat.
	Broken thermostat wires.	Run continuity check. Replace wires, if necessary.
Inadequate heating.	Dirty air ®lter.	Clean or replace ®lter as necessary.
	Gas input to unit too low.	Check gas pressure at manifold. Clock gas meter for input. If too low, increase
		manifold pressure, or replace with correct ori®ces.
	Unit undersized for application.	Replace with proper unit or add additional unit.
	Restricted air¯ow.	Clean ®lter, replace ®lter, or remove any restrictions.
	Blower speed too low.	Install ®eld-supplied motor and drive or adjust pulley to increase fan speed.
	Limit switch cycles main burners.	Check rotation of blower, thermostat heat anticipator settings, and temperature rise
		of unit. Adjust as needed.
	Too much outdoor air.	Adjust minimum position.
		Check economizer operation.
Poor ¯ame	Incomplete combustion (lack of	Check all screws around ¯ue outlets and burner compartment. Tighten as
characteristics.	combustion air) results in:	necessary.
	Aldehyde odors, carbon monoxide,	Cracked heat exchanger.
	sooting ¯ame, or ¯oating ¯ame.
		Over®red unit Ð reduce input, change ori®ces, or adjust gas line or manifold
		pressure.
		Check vent for restriction. Clean as necessary.
		Check ori®ce to burner alignment.
Burners will not	Unit is locked into Heating mode	Wait until mandatory one minute time period has elapsed or reset power to unit.
turn off.	for a one minute minimum.

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