Electric Furnace Heating Element Stays On [Solution & Analysis]

It can be very inconvenient when your electric furnace heating element stays on. Your house will heat up more than you want it to. Or, you’ll need to manually keep shutting it on and off. Keep reading to know why your heating elements are malfunctioning and what you should do about it.

Why Your Electric Furnace Heating Element Stays On

An electric furnace usually has two or more heating elements. They heat up the air that is later pushed out by the blower to your home. Your heating elements are controlled by the heat sequencer. When you turn on the furnace, the heat sequencer will allow the coils to heat up. Only one coil heats up at a time. After the first coil, the second one will start heating.

When the heating element is running non-stop usually, there is something wrong with the heat sequencer. Your heater can have one to two sequencers. If you have a double stack 10 KW heater, all the elements will be in one particular sequence. 

The heat sequencer metal flexes when the bottom is energized with low voltage. There’s a little pushpin inside the relay and it can get stuck causing the heating elements to stay closed and running all the time. 

You may get only constant heating element operation or constant heating element and blower operation. The former is dangerous as it can severely overheat your unit and cause a house fire. Having the blower on allows the heat to leave the much safer unit.

Why Do Heat Sequencers Fail?

It is natural for heat sequencers to fail after heavy use. They run in adverse conditions where there’s a lot of heat. Their lifespan is thus considerably shorter. Here are the reasons why your heat sequencer has gone bad.

Reason 1: Bimetal Switch Stuck 

The heat sequencer turns the heating elements on or off continuously maintaining a delay of 30-90 seconds. This is to make sure that a power surge doesn’t take place by trying to heat up more than one element at a time. Power surge will cause the heater safety switch to trip.

When the bimetal switch is stuck at an on or off position, it doesn’t function properly. In the on position, the heating elements will get continuous power. In the off position, the heating elements will get no power at all.

Reason 2: Straightening of The Bimetal Switch

The electric heater’s sequencer has a bimetal switch and heater coils. Voltage is first applied to the heating coils which is then transmitted to the bimetal switch. Due to the heat, the bimetal switch flex. As heat causes metal to expand in general. From this flexing, the heating elements get a power supply.

Over time the bimetal switch stays straightened out and doesn’t contract to its original size when cool. This means the heating elements will get constant power and keep running. 

Reason 3: Heater Not Used for Extended An Period

Extensive disuse is also a reason that can lead to a malfunctioning heat sequencer.

How To Fix A Heat Sequencer?

You can’t repair the heat sequencer once it has gone bad. All you can do is replace it. If your heating elements are running continuously, you should get professional advice. Don’t attempt to replace the sequencer yourself. Leave it to the professionals unless you have good experience with DIY repairs.

FAQs

How much does it cost to replace heat sequencers?

It will cost you about $300.

How much does an AC relay cost?

Anywhere between $80-300.

What controls the heating elements in most electric furnaces?

The thermostat and the heat sequencer control the heating elements in general.

How long do electric furnace elements last?

The heating elements of an electric furnace can last up to 15-25 years. 

Does an electric furnace have a fan limit switch?

Yes, electric furnaces do have fan limit switches to control the blower operation.

Conclusion

Now that you’re clear on what is going on with your heater, you can decide your next steps. If you have any queries, leave us a comment below. You’ll hear from us soon.

Note: Here you can read why your Goodman Furnace won’t stay lit and easy solution.

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