
Common no-heat causes we see
- Thermostat — dead batteries, wiring issue, or a failed unit
- Tripped reset — a "RESET" button on the burner that you can sometimes safely press once
- Out of fueluncommon with automatic delivery, but a tank gauge stuck above empty or a tripped propane shutoff can still starve the burner
- Clogged filter or air handlerrestricts airflow, trips the high-limit switch
- Failed igniter or flame sensorcommon on modern systems, usually a quick fix
- Bad zone valve or circulatorheat works in one part of the house but not another
- Cracked heat exchangera safety issue; the system locks out


