User`s manual

Table 17--Troubleshooting Guide-Heating
SYMPTOM CAUSE REMEDY
Water in gas line Drain. Install drip leg.
No power to furnace Check power supply fuses, wiring, or circuit breaker
Check transformer.
No 24-v power supply to contro{ circuit NOTE: Some transformers have internal overcurrent
protection that requires a cool-down period to reset.
Miswired or loose connections Check all wiring and wirenut connections
Burned-out heat anticipator in Replace thermostat.
Burners will not ignite, thermostat
Broken thermostat wire Run continuity check Replace wire if necessary
Check flame ignition and sense electrode positioning
Misaligned spark electrodes Adjust as necessary.
1Check gas line for air Purge as necessary
NOTE: After purging gas line of air, wait at least 5 minutes for any
No gas at main burners
gas to dissipate before attempting to light unit
2 Check gas valve.
Dirty air filter Clean or replace filter as necessary.
Check gas pressure at manifold match with that on
Gas input to furnace too low unit nameplate
Unit undersized for application Replace with proper unit or add additional unit.
inadequate heating. Restricted airflow Clean or replace filter Remove any restriction.
Use faster speed tap if available, or install alternate
Blower speed too low
motor.
Check rotation of blower, thermostat heat anticipator settings,
Limit switch cycles main burners
temperature rise of unit Adjust as necessary.
1Tighten all screws around burner compartment
Incomplete combustion results in: 2 Cracked heat exchanger Replace.
Poor flame characteristics. Aldehyde odors, carbon monoxide, sooting 3 Unit overtired. Reduce input (change orifices or
flame, floating flame adjust gas line or manifold pressure).
4 Check burner alignment
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