Model reference

Lennox ML193UH070P36B

Furnace

1 document22 error codes1 service mode

Available documentation

Service Manual

ML193UH Series Units Service Literature55 pg
Covers this model

MyPros+ Max

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Test values, resistance specs, and wiring references
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M+

M+ Max·Lennox Furnace

1 FLASH on my Lennox ML193UH070P36B

M+

Flame present with gas valve

From Service Manual 975817, p.29:

1.Access service mode to confirm the active fault code and read stored error history.

2.Measure control board supply voltage at test points. Expected: 12 VDC and 5 VDC.

3.Inspect all connectors on the main control for corrosion or backed-out pins.

Part WPW10804018

Electronic control board

Error codes (22)

CodeMeaning

1 FLASHFlame present with gas valve de-energized (Control 103085).2 FLASHESPressure switch closed with combustion air inducer de-energized (Control…3 FLASHESPressure switch open with combustion air inducer energized (Control 103085).4 FLASHESPrimary limit switch open (Control 103085).5 FLASHESRollout switch open (Control 103085).6 FLASHESPressure switch cycle lockout (Control 103085).7 FLASHESLockout 8 FLASHESLockout 9 FLASHESLine voltage polarity incorrect (Control 103085).LED OFFNo power to control or control hardware fault detected (Control 103085).LED ONNormal operation (Control 103085).LED1 ALTERNATING FAST FLASH / LED2 ALTERNATING FAST FLASHImproper main ground or line voltage below 90 volts.LED1 ALTERNATING SLOW FLASH / LED2 ALTERNATING SLOW FLASHWatchguard 1 hour LED1 FAST FLASH / LED2 FAST FLASHNormal operation LED1 FAST FLASH / LED2 SLOW FLASHMain power polarity reversed LED1 OFF / LED2 SLOW FLASHPrimary or secondary limit switch open LED1 ON / LED2 OFFCircuit control failure or control wired incorrectly.LED1 ON / LED2 ONRollout switch open or 12-pin connector improperly attached.LED1 SLOW FLASH / LED2 FAST FLASHLow flame signal LED1 SLOW FLASH / LED2 OFFFlame sensed without gas valve energized.LED1 SLOW FLASH / LED2 ONPressure prove switch open, or blocked inlet/exhaust vent, or pressure switch…LED1 SLOW FLASH / LED2 SLOW FLASHPower on

Service modes (1)

Diagnostic Code Recall (Control 103085)Press the push button switch on control 103085 for less than 5 seconds, then release

Full entry steps, exit procedures, and test sequences are available in Max.

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