Start with these quick checks
Many no-heat calls turn out to have a simple cause. Before you book service, take a few minutes to check:
- Thermostat: make sure it is set to Heat, the set temperature is above room temperature, and the batteries are fresh.
- Air filter: a clogged filter restricts airflow and can make the furnace overheat and shut down. Replace it if it looks gray or dusty.
- Power switch and breaker: furnaces have a switch that looks like a light switch near the unit. Confirm it is on and the breaker has not tripped.
- Vents and registers: open and unblock supply and return vents throughout the house.
- Gas supply: check that the gas valve to the furnace is open.
Common furnace problems and what they usually mean
Running but not heating
Often a dirty flame sensor, a failed igniter, a tripped limit switch, or a thermostat set to fan instead of heat.
Blowing cold air
Can point to ignition problems, a gas supply issue, or a furnace that keeps shutting off its burners for safety.
Strange noises
Squealing can mean a worn blower belt or motor bearing, while banging or booming may be delayed ignition that needs prompt attention.
Short cycling
Turning on and off every few minutes is often caused by restricted airflow, a dirty sensor, overheating, or a system that is oversized for the home.
What a full furnace diagnostic should include
- Testing the thermostat and control board
- Checking the igniter, flame sensor and burners
- Inspecting the blower motor and airflow
- Checking safety switches and limit controls
- Looking over the heat exchanger and venting
- Reviewing filters and ductwork for restrictions
A good technician checks the whole system instead of only the obvious symptom, then explains the repair options and costs before any work begins.
Repair or replace?
Most furnaces last around 15 to 20 years with regular maintenance. A helpful rule of thumb is to multiply the furnace's age by the repair cost. If the result is above $5,000, replacement often makes more financial sense. Below that, repairing is usually the better value.
Brands commonly serviced
Furnace repair is available for all major brands, including Carrier, Lennox, Trane, Goodman, Rheem and Bryant.
How to prevent the next breakdown
- Replace the air filter regularly during heating season.
- Schedule a furnace tune-up before winter.
- Keep the area around the furnace clear of storage and dust.
- Pay attention to new noises, smells or uneven heating and call early.
Frequently asked questions
Why is my furnace running but not heating?
The most common causes are a clogged filter, a thermostat set to fan, a failed igniter or flame sensor, or a limit switch shutting off the burners because the furnace is overheating.
Is it safe to keep using a furnace that short cycles?
It puts extra wear on parts and wastes energy. Replace the filter first, and if it continues, have it inspected.
Is same-day service available?
Yes. Zephyr offers same-day furnace service and 24/7 emergency response for no-heat calls.
Need your heat back today?
For fast, honest furnace repair in salt lake city, Zephyr Heating and Cooling offers same-day appointments, 24/7 emergency service, upfront repair options and licensed, insured technicians.
Call 801-471-0091 or visit zephyrheatingandcooling.com