Whether you have a heat pump, HVAC, or a furnace, winter will likely be the worse time of year for your system.

One problem you may experience is short cycling, where your system turns on and off more frequently than normal. This can be caused by a number of factors, but the good news is that it can usually be fixed relatively easily!

Here are some of the most common causes of short cycling and what you can do to fix them:

What Does Heat Pump Short Cycling Mean?

A heat pump’s short cycling means that your heat pump is turning on and off more frequently than it should and/or it doesn’t complete its normal cycle. What happens then is the system will briefly shut down to restart again.

The result is less heat in your home and a shorter lifespan for your heat pump! So, if you notice that your heat pump is short cycling, it’s important to take action to figure out the cause and fix the problem.

Related: Heat Pump Statistics

What Causes a Heat Pump to Short Cycle?

The thermostat is set too low

If your thermostat is set lower than the temperature outside, your heat pump will have to work overtime to try to reach the desired temperature.

This puts a lot of stress on the system and can cause it to short cycle. To sort this out, simply raise the thermostat a few degrees.

Related: Advantages and Disadvantages of Heat Pumps

The thermostat is set too high

If your thermostat is set too high, the heat pump will turn on and off frequently as it tries to reach the desired temperature.

This can also cause the system to overheat and shut down, leading to short cycling. To fix this, lower the thermostat a few degrees.

Related: Can A Bad Thermostat Cause Short Cycling? (POSSIBLY?)

Problem with the control board

The control board on your heat pump oversees all the functions of the system. If there is a problem with the control board, it can cause the heat pump to short cycle.

Your control board directly controls the thermostat, so if it’s not working properly, the thermostat may not be reading the temperature correctly. This can cause the heat pump to turn on and off more frequently than necessary. If this is the case, you’ll need to replace the control board.

Low refrigerant levels

If your heat pump is low on refrigerant, it won’t be able to cool your home effectively. This can cause it to short cycle as well as freeze up.

There’s a problem with the air filter

If the air filter is clogged, it can restrict airflow to the heat pump. This can cause the heat pump to work harder than necessary and may lead to short cycling. To sort this out, simply replace the air filter with a new one.

There’s a problem with the outdoor unit

If there’s a problem with the outdoor unit, it can cause the heat pump to short cycle. In essence, the outdoor unit is responsible for exchanging heat with the outside air.

To fix this, you’ll need to call a professional to diagnose and repair the problem.

The heat pump is too small

If the heat pump is too small for your home, it will have to work harder to heat or cool your home.

This can put a lot of stress on the system and may cause it to short cycle. To fix this, you’ll need to replace the heat pump with a larger one.

A damaged compressor

If you have a damaged compressor, it can cause your heat pump to short cycle.

Mainly because the compressor is responsible for circulating the refrigerant throughout the system.

To fix this, you’ll need to call a professional to diagnose and repair the problem.

Note: Many of the problems listed here will be the same for air conditioning units.

How to Fix Heat Pump Short Cycling

Now that we’ve gone over some of the most common causes of heat pump short cycling, let’s take a look at how you can fix it.

Note: For each one of these fixes, we recommend that you have a qualified HVAC/heat pump technician do the work.

Check the thermostat

The first thing you should do if you think your heat pump is short cycling is to check the thermostat.

If it’s set too low or too high, simply adjust it to a comfortable temperature and see if that fixes the problem.

Clean or replace the air filter

If the air filter is clogged, it can restrict airflow to the heat pump. This can cause the heat pump to work harder than necessary and may lead to short cycling.

To fix this, simply replace the air filter with a new one.

Check for low refrigerant levels

If your heat pump is low on refrigerant, it won’t be able to cool your home effectively.

This can cause it to short cycle as well as freeze up. This means the refrigerant will need to be topped up.

Inspect the outdoor unit

If there’s a problem with the outdoor unit, it can cause the heat pump to short cycle.

This is because the outdoor unit is responsible for exchanging heat with the outside air.

Replace the control board

If it’s not working properly, the thermostat may not be reading the temperature correctly.

This can cause the heat pump to turn on and off more frequently than necessary.

Does Short Cycling Matter?

Yes, it does matter. It is pretty much your first indication that something is wrong with your heat pump.

Short cycling puts a lot of stress on the system and can cause it to break down prematurely.

It can also lead to higher energy bills as the heat pump will be working harder than necessary.

So, if you think your heat pump is short cycling, be sure to have it checked out by a qualified technician.

They’ll be able to diagnose and fix the problem so that your heat pump can run efficiently for years to come.

FAQs

Is it bad if auxiliary heat comes on?

No. However, when the temperature outside drops, aux heat is a crucial part of keeping your heat pump operating properly. Because this sort of device works differently than a furnace, it can become chilly.

How often should a heat pump cycle on and off

Every two to three hours is when a heat pump should cycle on and off. The cycle of a heat pump should last 10 to 20 minutes. However, in the event of severe outside temperatures (below 30-40 degrees), a heat pump will operate constantly to maintain the temperature inside your home.

Is it normal for a heat pump to run constantly?

If temperatures drop below 30-40 degrees, it’s not uncommon for a heat pump to run constantly. The reason is, that the heat pump will be working harder to maintain the temperature inside your home.

Why does my heat pump shut off before reaching temperature?

This is down to the fact that your heat pump is short cycling. Short cycling is when the heat pump turns on and off more frequently than necessary. This can be caused by a number of different things, such as a dirty air filter or a thermostat that’s set too low or too high.

Why is my heat pump short cycling in heat mode?

This is because your heat pump has overheated. When this happens, the heat pump will turn off until it cools down. This is a safety feature to prevent the heat pump from overheating and damaging itself.

What causes an electric furnace to short cycle?

Your electric furnace will short cycle if you have a dirty air filter that is likely clogged with dirt. This means that your heat exchanger will overheat due to a lack of airflow, causing the furnace to turn off until it cools down.

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Passionate about helping households transition to sustainable energy with helpful information and resources.

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