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Robbins Heating & Air Conditioning, Inc. Blog

The Furnace Comes On After I Set My Thermostat: Is This a Problem?

Homeowners with gas furnaces want to see that the unit is always working properly, and understandably so. A problem with a gas furnace is not only an inconvenience—it could also indicate a safety issue. If you set the thermostat, but don’t hear the familiar sounds of the furnace right away, you may be concerned about the condition of your unit or your thermostat.

However, in most cases, a discrepancy between the furnace start-up time and when you set your thermostat is normal. Find out why furnaces start up late, or why you might hear your furnace running before the prescheduled settings, in today’s guide.

Thermostat delays are usually normal

If your furnace takes a couple of minutes to start warming you up, this is actually completely normal. In fact, a technician might be concerned if the furnace does start up right away, as this can indicate that a component of the system is not working properly. The fan switch is the component that causes the delay. This switch closes and allows the fan to start only after the furnace plenum has reached a certain temperature, which should be within a couple of minutes.

However, delays that last several minutes could indicate a larger problem, and even shorter delays could mean an issue when accompanied by a loud banging noise or a boom. If you suspect that your thermostat delay is longer than usual, call a technician ASAP.

Are you concerned about early startup?

Some homeowners struggle more with the furnace starting up too soon, rather than too late. They may set the thermostat to start up at 6:00 A.M., for example, only to wake up to the furnace running many minutes ahead of time. This problem also does not indicate a broken thermostat. Manny thermostats work with an adaptive recovery mode that attempts to get your home to the proper temperature by the time set on the thermostat. Because it will take some time to get warm, the furnace starts running before the scheduled time.

We install and service furnaces in Aztec, NM and the surrounding cities. Don’t waste your time with the run-around. Give Robbins Heating & Air Conditioning, Inc. a call and let us do it right the first time!

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