The red switch on your furnace: what it does
That red switch plate on or near your furnace is the emergency switch. It cuts power to the furnace, and because it looks just like a light switch, it gets flipped off by accident more than you’d think.
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From one of our jobs
A red emergency switch, right on the furnace
Right now: Find the switch near the furnace and make sure it’s on before you call about no heat.
The switch is there so anyone can shut the furnace down fast without hunting for the breaker. Flip it off and the furnace stops: no burner, no blower, no heat. Flip it on and the furnace starts again on the thermostat’s next call.
So if your heat is out, check this switch before anything else. If it’s on and the furnace still won’t run, the problem is further in, and that’s where we come in.
Quick answers
What people ask about the red furnace switch
What is the red switch on my furnace?
The emergency switch, sometimes labeled gas burner emergency switch. It turns the power to the furnace on and off, the same way a breaker would.
Why won’t my furnace turn on?
Check the red switch first. It’s often turned off by someone who thought it was a light. Then check the breaker, the thermostat batteries and the filter. If all of those are fine, call.
Should the furnace emergency switch be on or off?
On, all the time, unless you’re shutting the furnace down on purpose.
When should I use the emergency switch?
If the furnace is making a loud new noise, you see flames outside the burner area or something smells like it’s burning, switch it off. If you smell gas, leave the house and call your gas company from outside.
Who do I call if my furnace still won’t start?
Call SwiftPro at (703) 997-9757. We fix gas, propane and electric furnaces across Northern Virginia and tell you the price before any work starts.
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SwiftPro Heating, Cooling & Plumbing
4230 Lafayette Center Dr N, Chantilly, VA 20151
44679 Endicott Dr, Suite 211, Ashburn, VA 20147
SwiftPro Plumber & Water Heaters
4200 Lafayette Center Dr, Suite N, Chantilly, VA 20151
Virginia Class A contractor license #2705192276