HVACopediaLennox · Furnace
E345 Relay O failure
What the control is telling you
Listed in the 107045-XX table as an O relay failure; no action text given. The manual (including its troubleshooting section) gives no corrective procedure for this code; steps are general checks only.
Applies to: EL296UHV(X) series furnaces with integrated control 107045-XX only
Likely causes
- O relay failure on integrated control
Test and repair steps
- Check wiring at the O terminal and on-board link W951 (R to O) configuration for dual-fuel/heat pump use.
- If wiring and configuration are correct, suspect the integrated control; this manual gives no further procedure.
Settings for these units
- Recommended filter size by cabinet width · EL296UHV
- Recommended filter size by cabinet width · Lennox SL280UHV
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Source: Lennox EL296UHV(X) Unit Information / Service Literature, Ignition Control 107045-XX Diagnostic Codes table, p.44. Summarized in our own words; check the original manual for your model.
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