Furnace Repair in Sacramento

Shut it off and call right away if...

To shut it off, set the thermostat to Off, then turn off the switch on or near the furnace (it looks like a light switch). If you smell gas, leave the shutoff to the gas utility or fire department.

Common furnace problems we fix

Every start, a furnace runs a safety sequence: inducer fan, pressure switch, ignitor, gas valve, flame sensor, then blower. When one step fails, the furnace stops, so the symptom usually points to the part.

What you notice	Likely cause	Typical fix
Fan runs, no flame, tries again and locks out	Cracked or worn hot surface ignitor	Replace the ignitor and check voltage to it
Flame lights, then shuts off after a few seconds	Dirty flame sensor	Clean or replace the sensor, check the ground
Inducer hums but nothing lights, error code blinks	Pressure switch, blocked vent or plugged condensate trap	Clear the vent or drain, test or replace the switch
Heats for a few minutes, shuts off, repeats	Limit switch tripping from overheating	Fix the airflow problem first, then test the limit
Burners run but little or no air comes out	Failed blower motor or capacitor	Replace the capacitor or motor
Weak heat, high bills, furnace runs constantly	Clogged filter or restricted ducts	New filter, check ducts and registers

Ignitors

Most furnaces use a hot surface ignitor that glows like a toaster element. They are brittle, and a hairline crack is enough to stop ignition. We also check the voltage feeding it, since low voltage shortens ignitor life.

Flame sensors

The flame sensor is a thin metal rod that proves the burner is lit. A light coating on the rod weakens the signal, so the control board shuts the gas off as a precaution. Cleaning it is often the whole repair.

Pressure switches

The pressure switch confirms the inducer fan is pulling exhaust out of the furnace. It trips when the vent is blocked, the inducer is weak, or, on a 95% furnace, when the condensate trap or drain backs up. Replacing the switch without finding why it opened is a common mistake.

Limit switches

The high limit shuts the burners off when the heat exchanger gets too hot. If it keeps tripping, the furnace is not moving enough air. Clogged filters, closed registers, crushed ducts and a weak blower are the usual causes. If we find damaged ductwork, our air duct repair page explains the fix.

Blower motors and clogged filters

The blower moves both heat in winter and cooling in summer, so it works year round. A failing capacitor or motor shows up as humming, slow starts or no airflow. A filter that has not been changed in months is the most common cause of overheating and limit trips, and it is the easiest one to prevent.

Cracked heat exchangers and carbon monoxide

The heat exchanger keeps combustion gases separate from the air you breathe. After years of heating and cooling, the metal can crack, often at bends and seams. A crack can let carbon monoxide into the airstream or disturb the flame.

On a repair visit we look at the flame, measure CO in the flue and near the supply registers, and inspect the heat exchanger where we can reach it. If we confirm a crack, we will show you what we found, shut off the gas to the furnace and explain your options. Depending on the furnace's age and parts warranty, that can mean a heat exchanger replacement or a furnace replacement.

California law requires carbon monoxide alarms in homes with gas appliances, a fireplace or an attached garage. Put one on every level and outside sleeping areas, and replace them when they reach the end of life printed on the back.

Why furnaces fail during tule fog cold snaps

Sacramento winters are mild by most standards, with average December lows in the low 40s and a handful of nights at or near freezing. The hard weeks come when tule fog settles into the valley, usually after the first big rains of late fall. The sun stays hidden, daytime highs barely recover, and the furnace runs long cycles for days at a time.

That is when weak parts show up. A furnace that sat idle from March to November, then runs for hours on the first foggy cold spell, puts stress on ignitors, blower motors and capacitors all at once. Many Sacramento homes also have the furnace in the attic, where months of summer heat are hard on wiring and electronics. A fall furnace tune-up catches most of these problems before the cold arrives.

Quick checks before you call

• Thermostat. Is it set to Heat, with the setpoint above room temperature? Replace the batteries if it has them.
• Filter. If it is gray and packed, replace it and wait a few minutes.
• Power. Check the breaker and the service switch near the furnace.
• Furnace door. The front panel presses a safety switch. If it is loose, the furnace will not run.
• Condensate drain. On a high-efficiency furnace, a full or kinked drain line can shut it down.

Still no heat? Call us rather than resetting the furnace again and again.

How a furnace repair visit works

1. Call or book. Tell us what the furnace is doing and any blinking light codes. For no-heat emergencies we have 24/7 service.
2. Diagnosis. The technician reads the control board, walks through the start-up sequence and tests the part that is failing.
3. Safety check. We test for carbon monoxide and check the flame, venting and heat exchanger.
4. Clear options and price. You get the repair, the price and, if the furnace is near the end, an honest comparison with replacing it.
5. Repair and test. We fix it, run a full heating cycle and confirm the temperature rise and safety controls.

Repair or replace your furnace?

Most furnace repairs are worth doing. Replacement makes sense when the furnace is past about 15 to 20 years old, the heat exchanger is cracked, or repairs keep stacking up. If you replace, ask whether a heat pump fits better, since Sacramento's mild winters suit them well.

What does furnace repair cost in Sacramento?

What moves the price:

• The part. A flame sensor cleaning or ignitor costs far less than a blower motor, inducer or control board.
• Furnace type. Variable-speed blowers and communicating controls use more expensive parts.
• Location. Attic furnaces with tight access take longer than a furnace in a garage or closet.
• Warranty. If the part is still under the manufacturer's warranty, you may pay only for labor.

Where we repair furnaces

We repair furnaces across Sacramento and nearby communities in Placer, El Dorado and Yolo counties, including Carmichael, Citrus Heights, Fair Oaks and Elk Grove.

Furnace repair FAQ