Why is my heat pump not working?

Fast read

There is a variety of reasons why your heat pump may have stopped working, and all issues should be properly assessed.

If the heat pump has stopped working entirely, the first step of protocol would be to check the thermostat and power supply, as this is how the heat pump functions; if this is malfunctioning, it will cause faults to the system as a whole.

If you live in an area in which temperatures get extremely cold, your heat pump may be at risk of freezing; therefore, if your heat pump isn't working, it may be frozen. In this situation, turn on the defrost cycle manually and ensure no vents or filters are blocked.

Why has my heat pump stopped working?

A heat pump to generate hot water is a wise investment, assuming it doesn’t break down. Heat pumps are no different from other electrical devices because various problems can develop and lead to failure. There are numerous approaches to fixing them, though. This FAQ will give you an overview of why your heat pump is not working and explain a way forward. 

Experiencing a malfunction in your heat pump could be extremely upsetting, particularly if it serves as your primary source for heating your hot water. In the case of an air conditioning heat pump, a breakdown could mean being without cooling on a sweltering night.

Customers frequently call a maintenance expert to diagnose and repair their heat pump immediately. However, the owner can fix some minor problems with a heat pump. 

Knowing the most frequent causes of heat pump problems is crucial to be able to undertake such DIY analyses of the issue. By knowing when you do and do not require expert assistance, you can recognise the problem if it arises and save money in the long run. Additionally, you can discover various techniques for maintaining your pump’s peak performance. 

The top tips for troubleshooting your heat pump 

  • Listen for strange noises from the heat pump; they could indicate a problem with the compressor or other components. In such instances calling a servicing company could avoid more significant and costly issues.
  • Check the external part of the unit for any signs of damage; look for loose or damaged wires, leaks or rust.
  • If you have recently had any construction or renovations done to your home, it is possible that the unit was damaged or sucked in a lot of dust during the process.

If none are applicable, the following potential causes may help you identify why your heat pump has stopped working.

heat pump being installed
Check the external part of the heat pump unit for any signs of damage; look for loose or damaged wires, leaks or rust

Has your heat pump entirely stopped running?

If your heat pump stops working, the thermostat or power supply could be the most likely issue. Start by determining if there is power going to your unit. Ensure the power outlet is turned on and no circuit breaker has tripped. The breaker must be reset or replaced if it has blown or tripped. If you reset it and it trips again, you have an electrical risk, e.g. shortage, and to fix this, you need to call a qualified electrician. 

If your heat pump has stopped functioning once more after getting the thermostat updated recently, the possible flaws could be the thermostat’s mode not being fully compatible. In this case, seek guidance from a specialist to determine whether the thermostat is the right one for your system and if it’s in the correct setting. 

Has your heat pump frozen up?

If you notice that your heat pump has frozen and ceased operating, there is no need to panic. If you live in a cold climate, heat pumps freeze up relatively quickly; the outdoor unit of a heat pump can ice over and stop working.

Modern heat pumps have an inbuilt defrost cycle that turns on at a specific temperature, but this protection system can sometimes fail. So, your heat pump freezing up could indicate that this in-built system has failed. 

To resolve the issue, manually turn the defrost cycle on, if your unit has this option, to allow the condenser unit to defrost itself. Also, check if any air filters and vents are dusty or blocked. Your manual will clearly show where these are located. 

Does your heat pump fan not work?

If the blower/fan in your heat pump has stopped working, it is most likely caused by a broken belt. A broken belt can only be fixed by installing a new unit. Therefore a new belt must be purchased and fitted, in most cases, by a professional. 

Reclaim heat pump

Blown motherboard

The motherboard in the heat pump’s outside unit is the operation’s brain. After years of service, motherboards can malfunction, for example, due to corrosion, and if this is the case, unfortunately, the repair is not economically viable. This is because motherboards are expensive to replace and sometimes hard to source if the unit is older than 5 to 7 years old. 

Are your heat pump cycles wrong?

If your system consistently turns on and off, it is likely a thermostat issue. Check if your thermostat is malfunctioning throughout the day; if it is, you must recalibrate or replace it. 

Another cause for this issue could be a blocked filter. If an air filter is clogged up with dust (which happens over time), the heat pump cannot expel the air correctly. Thankfully this is an easy fix, as you can manually clean the filter. Less likely causes of this issue are a faulty valve or damaged fan.

Other causes

Power supply

Ensure that your system is getting the power it needs, and check circuit breakers to see if any have been tripped; resetting the power supply or circuit breakers might solve the issue.

Thermostat settings

The thermostat controls the heat pump’s operation and may be set to the wrong mode or temperature. It could also be malfunctioning.

Airflow issues

A dirty air filter, dirty coils, or a blocked condensate drain can cause a blockage in the system and can stop the heat pump from working. Regular maintenance can help to avoid any airflow issues.

man carrying air conditioner gas canister

Refrigerant Leak

Heat pumps need refrigerant to operate; therefore, if the refrigerant fluid leaks, the system may stop working. Always contact a professional in the case of a refrigerant leak.

Motor or compressor problems

The motors and compressor fail due to old age, lack of maintenance, or other factors. This would cause the system to stop working.

Faulty start capacitor

If your unit is not turning on, it could be due to a faulty start capacitor. The start capacitor provides the initial jolt of electricity to start the motor, and if it malfunctions, the motor won’t start.

Damaged ductwork

A blockage or damage, which will lead to air leakage, in the ductwork that distributes the heated or cooled air from the system to your home will impact the quality of heating or cooling you are receiving despite the system itself working. 

Software problem

Modern heat pumps often have complex digital controls. Sometimes a software glitch or firmware problem could cause your equipment issues. In this case, a professional system software update will be required.

Wiring issues

Heat pumps have complex electrical systems, and while it is a rare problem, sometimes wiring problems can occur and lead to the system not working correctly. If your investigation leads you to believe that wiring is the issue, e.g. a rat chewed on the supply cable, you should call a qualified professional to inspect the system.

So, if your system has stopped working, go through the potential list of causes, and if you cannot find a straightforward solution, book a professional company for the fault-finding mission.

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