The 8-step no-heat checklist
Work down this list in order — each step is safe for a homeowner and takes a minute or two:
- 1. Thermostat: set to HEAT, temperature above the room reading, fresh batteries if battery-powered
- 2. Furnace switch: the light-style switch on or beside the furnace is ON (it gets bumped more than you'd think)
- 3. Breaker: the furnace breaker in your panel hasn't tripped — flip it fully off, then on
- 4. Filter: pull it and look — a packed filter overheats the furnace and shuts it down
- 5. Furnace doors: access panels are fully seated; a safety switch cuts power when they're loose
- 6. Intake/exhaust pipes: the two PVC pipes outside aren't blocked by snow, ice, or nests
- 7. Condensate: on high-efficiency furnaces, a full drain pan or frozen line triggers a shutdown
- 8. Reset: turn the furnace switch off for 60 seconds, then back on, and give it 10 minutes to run its startup sequence
When to stop troubleshooting and call immediately
Two situations are not do-it-yourself territory. If you smell gas — rotten eggs — do not flip switches or relight anything; leave the house and call your gas utility and a professional from outside. And if your carbon monoxide detector alarms, get everyone out first. CO is odorless, and a failing heat exchanger is one of the ways it enters a home's air.
Short of those, repeated clicking without ignition, burning smells, or a furnace that starts and stops every few minutes (short-cycling) all warrant a professional diagnosis before serious damage develops.
Why no-heat calls spike on the coldest nights — and our answer
Extreme cold stresses every marginal component at once, which is exactly when you cannot wait days for help. True Comfort is open 24 hours a day, every day — a member of the family answers the phone, and our team has installed furnaces through blizzard conditions and -30° wind chills. Savings Plan members never pay an after-hours fee.
Frequently asked questions
Why is my furnace running but blowing cold air?
Common causes: the thermostat fan is set to ON instead of AUTO (the blower runs between heating cycles), a clogged filter has overheated the furnace and tripped its limit switch, or the ignition system is failing so the blower runs without a flame. Check the fan setting and filter first; ignition problems need a technician.
Why does my furnace keep turning on and off every few minutes?
Short-cycling usually points to overheating from a clogged filter or blocked airflow, a faulty flame sensor, or a system that was oversized for the home. Replace the filter first; if cycling continues, have it diagnosed — repeated short-cycling wears components quickly.
Is it safe to relight a furnace pilot light myself?
On an older furnace with a standing pilot, following the printed instructions on the unit is generally safe — but if the pilot won't stay lit, or you smell gas at any point, stop and call a professional. Repeated pilot failures usually mean a failing thermocouple, which is a quick professional fix.
Do you really answer at 2 a.m.?
Yes. True Comfort is open 24 hours a day, every day of the year, and a real person answers at 515-444-9154 — no phone maze. Emergency no-heat calls get a technician dispatched, not a callback the next business day.
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