Troubleshooting - Bryant 581B Installation & Service Instructions Manual

PROBLEM
Hardware failure.
(LED Off)
Limit switch fault.
(LED 2 Flashes)
Flame sense fault.
(LED 3 Flashes)
4 consecutive limit switch trips.
(LED 4 Flashes)
Ignition lockout.
(LED 5 Flashes)
Induced-draft motor fault.
(LED 6 Flashes)
Rollout switch fault.
(LED 7 Flashes)
Internal control fault.
(LED 8 Flashes)
LEGEND
IGC — Integrated Gas Unit Controller
LED — 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.
PROBLEM
Burners will not Misaligned spark electrodes.
ignite.
No gas at main burners.
Water in gas line.
No power to furnace.
No 24 v power supply to
control circuit.
Miswired or loose connections.
Burned-out heat anticipator in
thermostat.
Broken thermostat wires.
Inadequate heating. Dirty air filter.
Gas input to unit too low.
Unit undersized for application.
Restricted airflow.
Blower speed too low.
Limit switch cycles main burners.
Too much outdoor air.
Poor flame Incomplete combustion (lack of
characteristics. combustion air) results in:
Aldehyde odors, carbon monoxide,
sooting flame, or floating flame.
Burners will not Unit is locked into Heating mode
turn off. for a one minute minimum.

TROUBLESHOOTING

Table 18 — LED Error Code Service Analysis
CAUSE
Loss of power to IGC.
High-temperature limit switch
is open.
The IGC sensed flame that
should not be present.
Inadequate airflow to unit.
Unit unsuccessfully attempted
ignition for 15 minutes.
IGC does not sense that
induced-draft motor is operating.
Rollout switch has opened.
Microprocessor has sensed an
error in the software or hardware.
Table 19 — Heating Service Analysis
CAUSE
Check flame ignition and sensor electrode positioning. Adjust as needed.
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.
Drain water and install drip leg to trap water.
Check power supply, fuses, wiring, and circuit breaker.
Check transformer. Transformers with internal overcurrent protection require a cool
down period before resetting. Check 24-v circuit breaker, reset as necessary.
Check all wiring and wirenut connections.
Replace thermostat.
Run continuity check. Replace wires, if necessary.
Clean or replace filter as necessary.
Check gas pressure at manifold. Clock gas meter for input. If too low, increase
manifold pressure, or replace with correct orifices.
Replace with proper unit or add additional unit.
Clean filter, replace filter, or remove any restrictions.
Install field-supplied motor and drive or adjust pulley to increase fan speed.
Check rotation of blower, thermostat heat anticipator settings, and temperature rise
of unit. Adjust as needed.
Adjust minimum position.
Check economizer operation.
Check all screws around flue outlets and burner compartment. Tighten as
necessary.
Cracked heat exchanger.
Overfired unit — reduce input, change orifices, or adjust gas line or manifold
pressure.
Check vent for restriction. Clean as necessary.
Check orifice to burner alignment.
Wait until mandatory one minute time period has elapsed or reset power to unit.
Check 5-amp fuse on IGC, power to unit, 24-v circuit breaker, and
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.
Check the operation of the indoor (evaporator) fan motor. Ensure that
the supply-air temperature rise is in accordance with the range on the
unit nameplate.
Reset unit. If problem persists, replace control board.
Check operation of indoor (evaporator) fan motor and that supply-air
temperature rise agrees with range on unit nameplate information.
Check ignitor and flame sense electrode spacing, gas, etc. Ensure that
flame sense and ignition wires are properly terminated. Verify that unit
is obtaining proper amount of gas.
Check for proper voltage. If motor is operating, check the speed sensor
plug/IGC Terminal J2 connection. Proper connection: PIN 1-White,
PIN 2-Red, PIN 3-Black.
Rollout switch will automatically reset, but IGC will continue to lock out
unit. Check gas valve operation. Ensure that induced-draft blower
wheel is properly secured to motor shaft. Reset unit at unit disconnect.
If error code is not cleared by resetting unit power, replace the IGC.
IMPORTANT:
Refer to Table 19 — Heating Service Analysis for ad-
ditional troubleshooting analysis.
REMEDY
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REMEDY