Furnace repair in Spokane, heat back on fast.

Most no-heat calls come down to a short list of parts, and knowing which one you are probably looking at means you can tell a fair diagnosis from a sales pitch.

It runs, then shuts off after a few minutes. This is short-cycling, and the most common cause is the cheapest one: a clogged filter starving the furnace of air. Heat builds up where it should not, and a safety device called the limit switch shuts the burners down to protect the heat exchanger. Replace the filter first. If it keeps happening with a clean filter, the limit switch itself, a failing blower motor, or blocked return vents are the usual suspects.

It tries to light, then gives up. On most furnaces built in the last twenty-five years this is a dirty flame sensor — a thin metal rod that confirms the burner actually lit. When it gets coated, the furnace cannot prove there is a flame, so it shuts the gas off as designed. Cleaning it is a small job. The other frequent culprit is a cracked hot-surface igniter, also an inexpensive part.

Nothing happens at all. Work through the free checks before anyone is dispatched: thermostat set to heat and above room temperature, fresh thermostat batteries, the furnace’s own power switch on (it looks like a light switch nearby and gets flipped by accident more often than you would think), the breaker not tripped, the gas on, and the furnace door seated properly — a door that is not fully closed holds a safety switch open and the furnace will not run. Our furnace not turning on guide walks through every step in order.

It blows, but the air is cold. If the blower runs constantly and the air is cool, the thermostat fan setting may simply be on ON instead of AUTO. If the burners are not lighting at all, you are back to the ignition problems above. Our furnace blowing cold air guide covers the common causes and what a tech checks first.

Noises that mean stop now. A rumbling that continues after the burners shut off, a persistent smell of gas, or a carbon monoxide alarm are not diagnose-it-yourself situations. If you smell gas, leave the house first and call from outside. A cracked heat exchanger can leak combustion gases into the air you breathe, which is why a technician checks it before signing off on any heating repair.

Spokane furnaces run hard from October through March, and failures cluster around the first hard freeze — the night the system is finally asked for everything it has. That is also the night every heating company in the county is busy, which is why the dispatch here runs around the clock — see our 24/7 emergency HVAC page for what counts as a true after-hours call. Coverage also extends across the towns north and east of the city, where nights get colder and needs differ; the Spokane County service areas page covers what changes by town.

If your home heats with a heat pump rather than a gas furnace — which heats and cools from a single outdoor unit and is increasingly common in newer Spokane builds — the faults and diagnostic steps are different; our heat pump repair page covers those. And when summer arrives, the Spokane AC repair dispatch works the same way — same-day service, upfront quote before any work starts.