No-Heat Furnace Repair in Montana

Furnace Running but No Heat? Or Won't Start at All?

No heat comes in two forms, and both are common in Montana winters. Sometimes the furnace will not start at all — no sound, no fan, nothing. Sometimes it starts, the blower runs, and the air coming out of the vents is cold or barely warm. Both mean the furnace is not doing its one job, and both have a specific cause that a diagnosis will find. The fix is almost never a whole new furnace — it is usually one failed part.

The most common no-heat failures are small and fixable: a dead ignitor, a dirty flame sensor, a tripped breaker, a clogged filter, a failed thermostat, or a gas valve that is closed. A repair professional checks them in order, finds the one that failed, and replaces it.

Common Causes of No Heat

• Thermostat problems — dead batteries, a wrong setting, or a thermostat that has stopped talking to the furnace
• Tripped breaker or blown fuse — the furnace has no power at all
• Clogged air filter — restricted airflow overheats the furnace and trips the safety limit switch
• Failed ignitor or pilot — the furnace cannot light the burners
• Dirty flame sensor — the furnace lights, then shuts off within seconds because it cannot sense the flame
• Gas supply problems — a closed gas valve or an interrupted gas supply
• Blower motor failure — the burners fire but the warm air never reaches your rooms
• Limit switch or control board failure — the furnace's safety controls are shutting it down

What to Check Before You Call

1. Thermostat — set to HEAT, temperature set above the room temperature, and fresh batteries if it takes them.
2. Filter — if it is gray and packed with dust, replace it and try the furnace again.
3. Breaker — check the furnace breaker in your electrical panel. Reset it once; if it trips again, leave it off and call.
4. Gas valve — if you have a gas furnace, make sure the gas valve near the furnace is open.
5. Vents — make sure supply vents are open and not blocked by furniture or rugs.

If none of those fixes it, the problem is inside the furnace — and that is a job for a repair professional.

Our No-Heat Diagnosis

1. Listen and inspect — what is the furnace doing, and what is it not doing?
2. Check power and gas — breaker, switch, and gas supply confirmed first, because the simplest cause is the most common.
3. Test the ignition sequence — thermostat signal, ignitor, flame sensor, and gas valve, in order.
4. Test airflow — filter, blower, and ductwork, because a furnace that cannot move air cannot heat a home.
5. Explain and repair — you get the diagnosis, the price, and the repair, in that order.

Related Services

See also: Emergency Furnace Repair, Thermostat Repair, and Blower Motor Repair.