Payne Furnace Code 42
WarningShown as: 4 short flashes, 2 long flashes; minor codes 42.1, 42.2 and 42.3
Inducer RPM fault. 42.1 means no RPM feedback at start-up or before ignition proved; 42.2 means the RPM signal was lost for 5 seconds after ignition proved; 42.3 means the inducer is exceeding its model-specific RPM limit.
Manual wording: “42.1 NO RPM FEEDBACK - at start-up or before ignition proved. 42.2 NO RPM FEEDBACK - after ignition proved, signal was lost for 5 seconds. 42.3 EXCEEDING INDUCER RPM LIMIT”
Documented for: PG80MSU
Likely causes, most common first
- Improper vent sizing
- Restricted combustion air supply
- Failed inducer motor
- Improper or loose motor wiring or a bad connection
What you can safely check yourself
- Check the outdoor intake and exhaust pipes for snow, ice, leaves, or a nest blocking them
When to call a technician
The inducer motor and its wiring must be tested by a technician. A furnace that cannot run its inducer cannot vent combustion gases safely.
A Payne furnace throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.
Source
- PG80MSU: Installation, Start-up, Operating and Service and Maintenance Instructions (Payne, PG80MSU 80% multipoise gas furnace with 3-digit display and pressure transducer) · checked 2026-08-25