Lennox Furnace Code E110
Warning
Low line voltage. The 120-volt supply to the furnace is lower than the unit nameplate rating.
Manual wording: “Low line voltage. Line Voltage Low (Voltage lower than nameplate rating). Check power line voltage and correct.”
Documented for: EL296UHE and SLP98UHV series
Likely causes, most common first
- Utility supply voltage low or a brownout condition
- Undersized or loose branch circuit wiring feeding the furnace
What you can safely check yourself
- Check whether lights and other appliances in the house are also dimming or misbehaving
- Check that the breaker feeding the furnace is fully on
When to call a technician
Have an electrician or HVAC technician measure the supply voltage at the unit and correct the source of the low voltage.
A Lennox furnace throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Sources
- EL296UHE Service Literature (Corp. 1246-L10), Table 4 - Integrated Control Diagnostic Codes (Lennox Industries Inc., EL296UHE series 96% AFUE two-stage upflow/horizontal gas furnace (EL296UH045XE36B, EL296UH070XE36B, EL296UH090XE48C)) · checked 2026-08-25
- SLP98UHV Service Literature (Corp. 1029-L7), Table 14 - LED 7 Segment Status / Error Code and Integrated Control Diagnostic Codes (Lennox Industries Inc., SLP98UHV series variable-capacity communicating gas furnace (66,000-132,000 Btuh)) · checked 2026-08-25