What is a the Cooling Mode on a Heat Pump?

The cooling mode on a heat pump is when the heat pump is used to cool the air in your home. The refrigerant in the outdoor unit absorbs heat from the air, converting it to cold gas.

The cold gas is transformed to hot gas by applying pressure to it. The heated air is used in this process, which warms the cool liquid and condenses the gas into the warm liquid.

The amount of energy used in this process is reduced because the temperature difference between the two liquids is not as great as in a conventional air conditioner.

The Reason Your Heat Pump Is Stuck in Cooling Mode

If you are looking to troubleshoot why your heat pump is stuck in cooling mode, here are some potential reasons:

A Broken Reversing Valve

The number one reason why your heat pump would be stuck in heating mode is due to a broken reversing valve.

The reversing valve is what allows your heat pump to change from cooling mode to heating mode. If this valve is broken, then your heat pump will be stuck in either heating or cooling mode.

The valve can be found running parallel to your refrigerant line and is located in your outdoor unit.

If you know a little about air conditioning units, you’ll know that the reversing valve is what makes a heat pump and an air conditioner different.

The valve in your heat pump breaks down, not only will you not have heating. You won’t have any cooling either since the reversing valve is what makes the heat pump change directions.

The good news is, this is relatively easy for a technician to fix and/or replace.

Related: Where Is My Heat Pump Located? (ALSO IDEAL LOCATIONS)

Where is reversing valve on heat pump?

The valve will be located close to the compressor or condenser, and will have two refrigerant lines running to it – one from the compressor, and one from the evaporator.

It is soldered to the pipes or copper tubing, which are typically going in and out the device towards the other parts of the heat pump.

How do you reverse a valve stuck in cooling mode?

With modern heat pumps the reversing valve is self-automated. You will usually have a switch on the wall that you can set to the heating or cooling mode.

Older models may require you to physically change the reversing valve yourself. This is done by shutting down your heat pump, removing the access panel, and finding the reversing valve.

Once you’ve found it, turn the knob or lever to the desired setting and replace the access panel. Start up your heat pump again and test to see if it’s working in the correct mode.

Note: We would recommend you to contact a professional to do this for you as it can be dangerous working with refrigerants.

Related: Why Does Your Heat Pump Keep Shutting Off Prematurely?

What are the signs of a bad reversing valve?

The main sign that you have a bad reversing valve is when your heat pump is stuck in one mode.

If you think your reversing valve may be going bad, we recommend setting your heat pump to the opposite mode and seeing if it switches modes.

If it doesn’t, then it’s likely you have a bad reversing valve and will need to replace it.

What is the most common problem with reversing valves?

The most typical issue with a reversing valve is that it can get frozen in position. If it gets trapped in the heating position, there will be insufficient refrigerant flow to adequately cool your house.

Related: The Top Problems With Ground Source Heat Pumps

Reversing valve replacement cost

The cost to replace a reversing valve will depend on the heat pump model, the contractor, and the complexity of the job.

As a general rule, you can expect to pay between £350 and £500 ($450 and $600) for the replacement.

Related: How Much Does A Heat Pump Cost To Install And Run?

A Damaged Thermostat

Another reason why your heat pump might be stuck in cooling mode is due to a damaged thermostat. If your thermostat is not working properly, it might not be sending the correct signal to your heat pump to change modes.

To test if your thermostat is the issue, you can try turning it off and on again. You can also try changing the batteries in your thermostat. If neither of these things work, then you might need to replace your thermostat.

Refrigerant Loss/Leak

Sometimes the first sign of a refrigerant leak would be the smell of chemicals near your heat pump.

If you notice this, it’s important to shut off your heat pump immediately and call a technician.

Refrigerant leaks can cause serious damage to your heat pump and are also dangerous to your health.

You very rarely need to change the refrigerant in your heat pump, so if you notice any leaks, it’s best to call a professional.

A technician will be able to repair the leak and recharge your system with fresh refrigerant.

Can you lose refrigerant without a leak?

No, the only way to lose refrigerant is through a leak. If you think you might be losing refrigerant, the first thing you should do is check all the connections and fittings on your heat pump to make sure there are no leaks.

If you can’t find any leaks, then it’s likely that your heat pump was not charged correctly when it was installed. In this case, you will need to call a technician to recharge your system.

Faulty Compressor

If your compressor is not working properly, it can cause your heat pump to get stuck in cooling mode. The compressor is responsible for circulating refrigerant through your system.

If it’s not working, the refrigerant can’t flow and your heat pump won’t be able to change modes. A faulty compressor will need to be replaced by a qualified technician.

They will likely use a Refrigerant Leak Detector to find the leak, and then they will repair or replace the compressor.

Wiring Issues

Another potential cause of your heat pump getting stuck in cooling mode is wiring issues. If there are any loose wires or faulty connections, it can prevent your heat pump from switching modes.

Icy Evaporator Coil

If your evaporator coil gets too cold, it can cause your heat pump to get stuck in cooling mode. This usually happens when there’s a loss of refrigerant.

The first sign of this would be ice build-up on your evaporator coil. If you see this, you should shut off your heat pump.

How to prevent your heat pump from getting stuck in cooling mode

The best way to prevent your heat pump from getting stuck in cooling mode is to have it regularly serviced by a qualified technician.

A technician will be able to spot any potential problems with your heat pump and fix them before they become an issue.

Regular servicing will also help to prolong the life of your heat pump and ensure it runs efficiently.


Why does my heat pump blow cold air sometimes?

Depending on the model of your heat pump, it may well be in defrost mode. This happens when the evaporator coils get too cold and ice starts to build up.
The heat pump will then switch into a cooling mode to thaw the coils out. This can cause the air coming from your heat pump to be colder than usual for a short period of time.

How do I know if my heat pump is in defrost mode?

Most heat pumps will have a light that comes on when it’s in defrost mode. If you’re not sure, you can always check the manual for your specific model.
What should I do if my heat pump is in defrost mode?
If your heat pump is in defrost mode, there’s not much you can do other than wait for it to finish.
Once the coils have thawed out, your heat pump will switch back into heating mode and the air coming from it will return to normal.

Why does my heat pump blow hot air in cool mode?

This will be down to a broken reversing valve. The reversing valve is responsible for changing the direction of the refrigerant flow.
If it’s not working properly, the refrigerant will flow in the wrong direction and your heat pump will blow hot air.

How often should I have my heat pump serviced?

You should have your heat pump serviced at least once a year. This will help to keep it running smoothly and prevent any potential problems.
A service includes things like checking the refrigerant levels, cleaning the coils, and lubricating moving parts.
It’s also a good idea to check your heat pump regularly yourself and give it a quick clean if needed.

My heat pump only works in emergency mode

Your heat pump is trying warm the air in your home a lot quicker than usual, so it’s only using the compressor and fan.
This is why you’ll only feel a small amount of warm air coming from your heat pump.
If your heat pump is only working in emergency mode, you should check the thermostat to see if it’s set to emergency mode.

How do I reset my heat pump?

The reset button is normally located near the bottom of the outdoor unit. It may be labeled as a ‘reset’ button or a ‘fuse’.
To reset your heat pump, simply press the button and wait for the heat pump to restart.
If your heat pump doesn’t have a reset button, you’ll need to switch it off at the fuse box. Leave it for a few minutes before turning it back on again.

About the Author

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

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