Furnace Not Heating? Check These First

Quick checks before you call

Do these in order. They take a few minutes and solve a lot of no-heat calls.

• Set the thermostat to Heat and raise the temperature a few degrees above the room. Replace the batteries if the display is blank or dim.
• Check the breaker panel for a tripped furnace breaker. Reset it once. If it trips again, leave it off.
• Look for the switch near the furnace that looks like a light switch and make sure it is on.
• Check the air filter. A badly clogged filter can make the furnace shut off before the house warms up.
• Make sure the vents and return grilles are open and not blocked by furniture or rugs.

Why a furnace will not heat

When the quick checks do not fix it, the problem is usually one of these:

• A dirty flame sensor or a failed igniter, so the burner will not stay lit.
• A clogged filter or weak airflow that makes the furnace overheat and shut down.
• A failed blower motor or capacitor.
• A bad control board or a thermostat that is not sending the signal to start.
• A pilot light or gas supply problem.
• A blocked condensate line or a safety switch that has tripped.

What not to do

• If you smell gas, leave the house and call your gas company or 911 from outside. Do not turn anything on or off.
• Do not keep resetting a breaker that trips again. That points to an electrical problem.
• Do not open the furnace panels or work on the gas or electrical parts yourself.
• Do not use an oven or a stove to heat the house.

When to call Cool Guys

Call us if the checks above do not bring the heat back, if the furnace starts and shuts off again, if the breaker keeps tripping, or if you hear clicking or banging but get no warm air. A technician finds the cause, tells you the price before any work begins, and fixes it. The dispatch fee is $49 and it is waived with any repair. If the furnace is near the end of its life, we will show you the repair and a replacement option side by side. Replacement estimates are always free.