Why Won\u2019t My Furnace Turn On?

A furnace that will not start on a cold Utah County morning is stressful. Several common issues can be checked before you call for service.

Quick answer: A furnace that will not turn on is often caused by a thermostat issue, a tripped breaker, a clogged filter, a dirty flame sensor, or a safety switch that shut the unit down. Check the thermostat, breaker, and filter first, then call a technician if it stays off.

Common Causes

  • Thermostat set wrong, dead batteries, or a wiring issue
  • Tripped breaker or a blown fuse
  • Very dirty filter triggering a safety shutoff
  • Dirty flame sensor so the burners will not stay lit
  • Blower door not fully closed, which opens a safety switch

What You Can Check Yourself

  1. Set the thermostat to heat and raise it above room temperature, and replace the batteries
  2. Check the breaker and reset it one time
  3. Replace a dirty filter and make sure the furnace panel is fully closed

When to Call Air Plus Heating

If the quick checks above do not solve it, the problem needs a trained technician. Air Plus Heating has served Utah County since 1982 with honest pricing, free estimates, and same day and 24/7 emergency service. Learn more about our furnace repair in Utah County, or see all of our HVAC troubleshooting guides.

Related Questions

Why Won’t My Furnace Turn On?

A furnace that will not turn on is often caused by a thermostat issue, a tripped breaker, a clogged filter, a dirty flame sensor, or a safety switch that shut the unit down. Check the thermostat, breaker, and filter first, then call a technician if it stays off.

Why does my furnace start then shut off quickly?

This short cycling is often a dirty flame sensor, a clogged filter, or an overheating limit switch. It should be cleaned or checked so it runs safely.

Should I keep resetting my furnace?

Reset the breaker only once. If it trips again or the furnace still will not run, stop and call a technician, since repeated resets can be unsafe.

Need HVAC Help in Utah County?

Call (801) 362-5115 for same day and 24/7 emergency service, or request a free estimate.

📞 Call Now: (801) 362-5115