Model reference
Lennox 90UGFA3-75
Furnace
1 document13 error codes
Available documentation
Service Manual
- 90UGF Series Service Literature40 pg
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Error codes (13)
CodeMeaning
LED#1 Alternating Fast Flash / LED#2 Alternating Fast FlashImproper main ground or line voltage below 75 volts; OR broken ignitor; OR open…LED#1 Alternating Slow Flash / LED#2 Alternating Slow FlashWatchguard modeLED#1 Fast Flash / LED#2 Slow FlashMain power polarity reversed; switch line and neutral.LED#1 OFF / LED#2 ONCircuit board failure or control wired incorrectly.LED#1 OFF / LED#2 Slow FlashPressure switch open or has opened 5 times during a single call for heat; OR…LED#1 ON / LED#2 OFFCircuit board failure or control wired incorrectly.LED#1 ON / LED#2 ONCircuit board failure or control wired incorrectly.LED#1 ON / LED#2 Slow FlashRollout switch open OR 9-pin connector improperly attached.LED#1 Simultaneous Fast Flash / LED#2 Simultaneous Fast FlashNormal operation, signaled when heating demand initiated at thermostat.LED#1 Simultaneous Slow Flash / LED#2 Simultaneous Slow FlashPower on, normal operation; also signaled during cooling and continuous fan.LED#1 Slow Flash / LED#2 Fast FlashLow flame signal, measures below 0.7 microamps.LED#1 Slow Flash / LED#2 OFFFlame sensed without gas valve energized.LED#1 Slow Flash / LED#2 ONPrimary or secondary limit open; limit must close within 5 trials (boards…Related Lennox furnace models
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