Lennox Furnace Code E310
Warning
Discharge air temperature sensor failure. The sensor is reading shorted or out of range. There is no error if the sensor is simply disconnected. The code is activated during Field Test mode.
Manual wording: “Discharge error sensor failure - No error if disconnected. Only shown if shorted or out-of-range. Discharge air temperature(DATS) out of range, code is activated during "Field test mode".”
Documented for: SLP98UHV series
Likely causes, most common first
- Failed or shorted discharge air temperature sensor
- Damaged sensor wiring
What you can safely check yourself
- Turn the furnace power switch off for 30 seconds and back on once
When to call a technician
Checking sensor resistance against the temperature charts and replacing the sensor is a technician job.
A Lennox furnace throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Source
- 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