Carrier WEATHERMASTER 48/50Z030-105 Operation And Service Manual page 87

PROBLEM
Burners Will Not Ignite.
Inadequate Heating.
Poor Flame Characteristics.
Burners Will Not Turn Off.
PROBLEM
No Heat.
Table 72 — Gas Heating Service Analysis
CAUSE
Active alarm.
No power to unit.
No power to IGC (Integrated Gas Control).
Heaters off due to time guard to prevent short
cycling.
Thermostat or occupancy schedule set point not
calling for Cooling.
No gas at main burners.
Water in gas line.
Dirty air filters.
Gas input too low.
Thermostat or occupancy schedule set point only
calling for W1.
Unit undersized for load.
Restricted airflow.
Too much outdoor air.
Limit switch cycles main burners.
Incomplete combustion (lack of combustion air)
results in: Aldehyde odors, CO, sooting flame, or
floating flame.
Unit is in Minimum on-time.
Unit running in Service Test Mode.
Table 73 — Electric Heat Service Analysis
CAUSE
Power failure.
Fuse blown or circuit breaker tripped. Check CB1,
CB2, and CB3.
Thermostat occupancy schedule set point not call-
ing for Heating.
No 24 vac at primary contactor.
No power (high voltage) to L2 of primary contactor. Check safety switches "one-shot" backup and auto limit.
Bad electrical elements.
Check active alarms using ComfortLink™ scrolling
marquee.
Check power supply, fuses, wiring, and circuit breakers.
Check fuses and plugs.
Check using ComfortLink scrolling marquee.
Check using ComfortLink scrolling marquee.
Check gas line for air and purge as necessary. After purg-
ing gas line of air, allow gas to dissipate for at least 5 min-
utes before attempting to re-light unit.
Drain water and install drip.
Replace air filters.
Check gas pressure at manifold. Refer to gas valve adjust-
ment in Installation, Start-up, and Service Manual.
Allow time for W2 to energize.
Decrease load or increase of size of unit.
Remove restriction.
Check economizer position and configuration. Adjust mini-
mum position using ComfortLink scrolling marquee.
Check rotation of blower, thermostat heat anticipator set-
tings, and temperature rise of unit. Adjust as needed.
Check all screws around flue outlets and burner compart-
ment. Tighten as necessary.
Cracked heat exchanger, replace.
Unit is over-fired, reduce input. Adjust gas line or manifold
pressure.
Check vent for restriction. Clean as necessary.
Check orifice to burner alignment.
Check using ComfortLink scrolling marquee.
Check using ComfortLink scrolling marquee.
Call power company.
Replace fuse or reset circuit breaker.
Check using ComfortLink scrolling marquee.
Check transformer and circuit breaker.
Power off unit and remove high voltage wires. Check resis-
tance of heater, replace if open.
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REMEDY
REMEDY