Bryant 581A Installation And Service Instructions Manual page 36

PROBLEM
Burners will not ignite.
Inadequate heating.
Poor flame characteristics.
Burners will not turn off.
LEGEND
GR — Ground
Table 19 — Heating Service Analysis
CAUSE
Misaligned spark electrodes.
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.
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.
Incomplete combustion (lack of combustion air)
results in:
Aldehyde odors, CO, sooting flame, or floating
flame.
Unit is locked into Heating mode for a one minute
minimum.
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 if necessary.
Check all wiring and wire nut 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 alternate motor, if applicable, 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
power to unit.
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REMEDY