Why Does Electric Furnance Come on Run Turn Off and Turn on Again
If you notice that your furnace blower is turning on and off when it shouldn't, yous'll want to have that checked every bit soon every bit possible. Non only does this decrease your comfort, information technology can damage your furnace.
So what's causing this? Well, it depends on your situation.
Is your blower turning on/off constantly during a heating cycle? If and so, information technology'southward near probable caused by
- Poor duct pattern
- Abnormally cold temperatures inbound the estrus exchanger
- Abnormally hot temperatures in the estrus exchanger
Is your blower turning on/off when your furnace isn't heating? If so, it'due south most probable caused past a bad fan limit switch.
We'll go over what you can practice on your own to solve your problem and when you'll demand a professional.
But showtime, let's take a quick look at how your furnace blower works in normal operation to determine whether you actually have a problem or not.
How your furnace blower unremarkably works
In normal operation, your furnace blower fan should come on 1.5 to 3 minutes after your thermostat calls for estrus and should turn off several minutes later on the heating cycle ends.
Your blower should run constantly until the heating bicycle ends.
When your furnace isn't actually heating, though, your furnace blower shouldn't be running at all.
So, if your blower is turning on/off during a heating bicycle or later the phone call for estrus stops, you take a trouble.
Now, allow'due south await at what'due south causing your blower to "misbehave" in both of these situations…
If your blower is constantly turning on/off during a heat bicycle…
...you have one of these 4 bug:
- Ductwork that is leaky or designed poorly
- A furnace that is oversized for the domicile
- Abnormally depression temperatures in the heat exchanger
- Abnormally loftier temperatures in the heat exchanger
Then, what can y'all do to end your blower from constantly turning on and off during a heat cycle?
Unfortunately, you'll need a professional to solve near of the problems listed above. But before you call a professional person, two things you can exercise to try and solve the problem are:
1. Check for a dirty air filter and replace if needed. A clogged filter limits the amount of cool air that passes over the heat exchanger, causing it to overheat and close off. At the same time, your blower turns on to assist cool it down. Equally soon every bit the estrus exchanger cools downward, though, the burners turn back on (because the thermostat is nonetheless calling for heat) and the process repeats.
And so, if your air filter looks similar the one to the right, replace it immediately and meet if that fixes the trouble.
2. Check for a dirty air handler blower fan. Similar to a clogged filter, dirt on the blades of the air handler fan volition decrease cold airflow over the estrus exchangers, resulting in the same blower on/blower off pattern. And so, if your air handler looks like the one below, try wiping the blades carefully with a dry towel or toothbrush.
If you're withal noticing that your blower turns on and off constantly during a heat cycle, yous'll demand to take a professional person inspect your unit of measurement to find the problem and correct it.
If your blower is constantly turning on/off when the furnace isn't heating…
...y'all most likely have a bad fan limit switch.
Your furnace fan limit switch is basically a command arrangement that determines when the furnace blower assembly should turn on and off. The system uses a "temperature probe" to observe temperature changes inside the heat exchanger (run across paradigm beneath) and turns your blower on and off in response.
Simply since temperatures within the heat exchanger should stay relatively stable when the furnace burners aren't on, your blower fan shouldn't be needed at all.
Then if your furnace blower is turning on and off when the furnace isn't in a oestrus cycle, information technology unremarkably means the fan limit switch is defective.
Unless you lot're familiar with the components of your fan limit switch and how it works, we suggest letting a professional repair or supplant the switch.
Need help from a MN tech?
If you're not sure why your furnace blower is cycling on and off when it shouldn't be, we're here to assist.
If yous live in the Minneapolis-St. Paul area, schedule your appointment with MSP today.
We'll transport a tech over immediately to take a look at your arrangement and fix the problem in no time.
Source: https://mspplumbingheatingair.com/blog/why-does-my-furnace-blower-turn-on-and-off-constantly