![background image](http://html.mh-extra.com/html/carrier/weathermaker-48aj020/weathermaker-48aj020_operating-and-service-manual_2560309077.webp)
77
Table 89 — Gas Heating Service Analysis
Table 90 — Electric Heat Service Analysis
PROBLEM CAUSE
REMEDY
Burners Will Not Ignite.
Active alarm.
Check active alarms using
Comfort
Link™ Scrolling
Marquee.
No power to unit.
Check power supply, fuses, wiring, and circuit breakers.
No power to IGC (Integrated Gas Control).
Check fuses and plugs.
Heaters off due to time guard to prevent short
cycling.
Check using
Comfort
Link Scrolling Marquee.
Control calling for Cooling.
Check using
Comfort
Link Scrolling Marquee.
No gas at main burners.
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.
Water in gas line.
Drain water and install drip.
Inadequate Heating.
Dirty air filters.
Replace air filters.
Gas input too low.
Check gas pressure at manifold. Refer to gas valve adjust-
ment in Installation, Start-up, and Service Manual.
Control calling for W1only (low heat).
Allow time for W2 to energize.
Unit undersized for load.
Decrease load.
Restricted airflow.
Remove restriction.
Too much outdoor air.
Check economizer position and configuration. Adjust mini-
mum position using
Comfort
Link Scrolling Marquee
.
Limit switch cycles main burners.
Check rotation of blower, thermostat heat anticipator set-
tings, and temperature rise of unit. Adjust as needed.
Poor Flame Characteristics.
Incomplete combustion (lack of combustion air)
results in: Aldehyde odors, CO, sooting flame, or
floating flame.
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.
Burners Will Not Turn Off.
Unit is in Minimum on-time.
Check using
Comfort
Link Scrolling Marquee.
Unit running in Service Test Mode.
Check using
Comfort
Link Scrolling Marquee.
PROBLEM CAUSE
REMEDY
No Heat.
Power failure.
Call power company.
Fuse blown or circuit breaker tripped.
Replace fuse or reset circuit breaker.
Thermostat occupancy schedule set point not call-
ing for Heating.
Check using
Comfort
Link Scrolling Marquee.
No 24 vac at primary contactor.
Check transformer and circuit breaker.
No power (high voltage) to L2 of primary contactor. Check safety switches “one-shot” backup and auto limit.
Bad electrical elements.
Power off unit and remove high voltage wires. Check resis-
tance of heater, replace if open.
Summary of Contents for WEATHERMAKER 48AJ020
Page 95: ...95 Fig 13 Typical Main Control Box Wiring Schematic A48 7787 ...
Page 96: ...96 TO NEXT PAGE Fig 14 Auxiliary Control Box Wiring Schematic A48 7294 ...
Page 98: ...98 Fig 15 Typical 2 Stage Gas Heat Wiring Schematic Size 051 and 060 Units Shown A48 6866 ...
Page 102: ...102 TO NEXT PAGE Fig 18 Typical Power Schematic Size 051 and 060 Units Shown A48 7298 ...
Page 104: ...104 Fig 19 Controls Option Wiring Schematic A48 7810 ...
Page 105: ...105 Fig 20 Small Chassis Component Location Size 020 035 Units A48 7301 ...
Page 106: ...106 Fig 21 Large Chassis Component Locations Size 036 060 Units A48 7302 ...