HVACopediaLennox · Furnace · Standby/shutdown
Continuous fan with heat or cool calls
What happens, in order
- Fan switched to ON at the thermostat the G call runs the blower at fan speed and powers the EAC terminal
- If a call for heat arrives, the blower keeps running at fan speed until the 30 second heat delay is over, then goes to heating speed; EAC and HUM stay on
- If a call for cooling arrives, the blower moves to cooling speed and EAC stays on
- When the call ends, the HUM terminal drops after the inducer post-purge
- After the blower off delay the blower returns to fan speed and EAC stays energized
Timings and thresholds
| Item | Value |
|---|---|
| Heat speed switch delay | 30 s |
| Inducer post-purge | 5 s |
Applies to: EL195UHNE, ML180UHEK
Models
More Lennox furnace sequences
- Single-stage furnace ignition retries and watchguard · Ignition
- Two-stage furnace ignition retries and watchguard · Ignition
- Single-stage furnace gas heating cycle · Heating
- Two-stage furnace heating with single-stage thermostat · Heating
- Two-stage variable speed furnace heating with two-stage thermostat · Heating
- Cooling call on single-stage furnace blower · Cooling
- Two-stage variable speed cooling call · Cooling
Related
Lennox error codes · Lennox tips · Lennox parts · All Lennox sequences
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Source: Lennox EL195UHNE service manual Corp 1801-L1 (rev 04-2024), Sequence of Operation pp.9-10 and 49-54; Lennox ML180UHEK service manual 100166, Heating Ignition Sequence p.11 and Sequence of Operation pp.36-40. Written in our own words; timings can differ by model and software version, so check the manual for your exact unit.
For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.