Heating help · Surprise, Arizona
Heater Not Working? What to Check When There’s No Heat
The first cold night of the year is when most heaters show their problems. Before you call, a few safe checks can get the heat back on. If they don’t, we answer around the clock.
The short answer
If your heater won’t turn on, make sure the thermostat is set to HEAT and a few degrees above room temperature, replace the thermostat batteries, reset any tripped breaker for the furnace or air handler, check the furnace power switch and that the door panel is fully closed, and replace a clogged filter. Still no heat? Call a technician.
Step by step
Safe checks when there’s no heat
1. Thermostat
Set it to HEAT and raise it 3–5 degrees above the room. A blank screen usually means dead batteries or a tripped breaker.
2. Breakers
Check the panel for tripped breakers labeled furnace, air handler, heat pump or heat strips. Reset once only.
3. Furnace switch
Most furnaces and air handlers have a switch that looks like a light switch nearby. Make sure it’s on.
4. Door panel
Furnaces have a safety switch that keeps the system off if the front panel isn’t seated tightly.
5. Filter
A badly clogged filter can make the system shut itself off to prevent overheating.
6. Gas supply
For gas heat, make sure the gas valve to the furnace is open and other gas appliances work.
Smell gas (rotten eggs) or hear a carbon monoxide alarm? Don’t troubleshoot. Leave the house, then call 911 or Southwest Gas from outside. Call us once everyone is safe.
What it might be
Common reasons a heater won’t start
Thermostat problems
Dead batteries, a loose wire, the wrong mode or an old thermostat that no longer calls for heat.
Ignition failure
A worn hot surface igniter or dirty flame sensor keeps a gas furnace from lighting or staying lit.
Tripped safety switch
Overheating, a backed-up condensate drain or a loose door panel can lock the system out.
Blower motor or capacitor
If you hear a hum but no air moves, the blower motor or its capacitor may have failed.
Control board error
A blinking light on the furnace board is an error code. Note the pattern before you call; it helps us diagnose faster.
Heat pump issues
A failed contactor, outdoor fan or reversing valve, or heat strips that won’t engage.
Heater running but blowing cold? See Heater Blowing Cold Air.
Avoid the next cold night
Most no-heat calls are preventable
A fall heating tune-up catches worn igniters, dirty flame sensors, weak capacitors and clogged drains before they leave you without heat. Annual maintenance plans start at $120 a year. Book a tune-up before the holidays →
Common questions
No heat: questions
Why won’t my heater turn on?
The most common causes are a thermostat set wrong or with dead batteries, a tripped breaker, the furnace power switch turned off, a loose door panel, a clogged filter, or a failed igniter or flame sensor.
What should I do if my heat goes out at night?
Do the safe checks: thermostat, breakers, furnace switch, door panel and filter. If there’s still no heat, call us. We answer 24/7 and don’t charge extra just because it’s after hours.
Why is my furnace light blinking?
A blinking light on the control board is a diagnostic code. Count the blinks and tell the technician; the legend is usually on the inside of the furnace door.
Can I reset my furnace?
You can turn the furnace switch or breaker off for a minute and back on once. If it locks out again, something is causing it to shut down and it needs a technician.
Is no heat an emergency in Arizona?
It can be on cold nights, especially for older adults, babies or anyone with health concerns. Call any time, and call 911 first if you smell gas or a carbon monoxide alarm sounds.
How much does a heating repair cost?
It depends on the part. A diagnostic or service call typically runs $95–$250 and is free with any approved repair, and you get the price before work starts.
No heat? Call or text, 24/7.
Furnace, heat pump and rooftop gas pack repair across Surprise and the West Valley.
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