Lennox furnace E113: High line voltage
E113 means the incoming line voltage is above the furnace's nameplate rating. Lennox's action is to bring the supply within range; normal operation resumes five seconds after it recovers.
Applies to: Lennox gas furnaces with a seven-segment diagnostic display on the control board, such as the ML193UHEK, per installation instructions 508565-01.
What it means
Less common than low voltage and less discussed, but harder on electronics. High supply voltage stresses the control board, the motor windings and anything with a capacitor in it, and it shortens component life without producing any obvious symptom until something fails. The furnace measuring this and reporting it is the useful part — a house with chronically high supply voltage will quietly age every appliance in it, and a stored E113 is often the first written evidence anyone has of that.
Most common causes
- A utility supply running high, which affects the whole house.
- A transformer tap set incorrectly on the utility side.
- Light loading on a circuit that normally carries more, raising the measured voltage.
- A wiring fault producing an abnormal reading.
How to diagnose it
- Note whether other electronics in the house have been failing unusually often — that is the pattern high supply voltage produces.
- Note whether the code is constant or intermittent.
- Measurement is technician or electrician work.
- If the whole house is affected, the utility needs to know.
How to fix it
- Provide power voltage within the proper range, which is Lennox's instruction.
- If the supply is genuinely high at the meter, this is a utility matter rather than an HVAC one.
- Normal operation resumes five seconds after the fault recovers.
- Worth acting on even though the furnace keeps running — the damage is cumulative.
Notes
The nameplate on the furnace states the rating this is measured against, so what counts as high is specific to the unit rather than a universal number.
Related
All codes for this manufacturer
Lennox furnace alert codes — every code, with what differs between models.