Even though this article is about ground source heat pump (GSHP) problems, they don’t normally give homeowners much trouble.

GSHP systems are reliable and durable, with an expected lifespan of 25 years or more.

But, like any mechanical system, they can break down or require repair from time to time.

Here are the 15 most common problems that ground source heat pump owners face:

1. Faulty Heat Pump Sensors

One of the main problems you will have with any type of heat pump, ground source or otherwise, is faulty sensors.

These sensors are responsible for telling the heat pump when to turn on and off, as well as regulating the temperature.

If they are not working properly, it can cause the heat pump to overheat or cycle on and off too frequently.

You can usually tell if your heat pump has faulty sensors by monitoring the unit closely.

If you notice that it is turning on and off more often than usual, or that the temperature in your home is not consistent, then there is a good chance that the sensors are to blame.

Related: Heat Pump Statistics

2. Faulty Heat Pump Circulation Pumps

The heat pump circulation pump is responsible for circulating the refrigerant through the system. If this pump fails, it can cause the entire system to break down.

In most cases, a faulty heat pump circulation pump will make a loud noise when it is turned on.

If you hear this noise, it is important to have the pump checked by a professional as soon as possible.

Related: Where Do Heat Pumps Work Best? (FULLY EXPLAINED)

3. Controller Problems

No matter which type of heat pump you have, it will be controlled by a controller. This controller is responsible for regulating the temperature and ensuring that the system is running efficiently.

If the controller on your heat pump is not working properly, it can cause a number of problems, including poor heating and cooling performance, as well as increased energy costs.

4. Corroded Heat Pump Flexi Hoses

Since plant rooms are not heated, the heat pump’s flexi hoses can become corroded over time. This corrosion can lead to leaks, which can be a serious problem.

The lifespan of a flexi hose is typically around 5 years. However, if you live in an area with a lot of salt in the air, it is important to check your hoses more often.

If you notice that your heat pump is leaking, it is important to have the flexi hoses checked by a professional. In most cases, they will need to be replaced.

How often should flexible hoses be replaced?

I recommend replacing your flexi hose every 5 years to avoid corrosion and leaks.

To be honest, if you have scheduled maintenance on your heat pump regularly, these flexi hoses will also be checked and replaced if needed.

What causes flexi hoses to burst?

When the braided lining fails, these hoses tend to burst. This may be due to corrosion or physical harm, although it can also happen as a result of wear and tear.

At some time in the future, this inner core will burst. Because a ruptured pipe might release water at a rate of 1,500 litres per hour, and flooding is possible.

Related: How Do I Keep My Patio From Flooding? (Out of the Box Solutions)

5. Heat Pump Compressor Failure

Not as popular as the other GSHP problems, compressor failure is still one of the issues you may face.

The compressor is responsible for circulating the refrigerant through the system. If it fails, it can cause the entire system to break down.

This can happen when the heat pump in over six or seven years of age. In some cases, the compressor may also fail due to a lack of maintenance.

Compressors are the main mechanical part of the heat pump and undergo the largest amount of stress.

This normally happens when they either starting or stopping. As a result, the bearings can become worn out, which will eventually lead to compressor failure.

You can usually tell if your heat pump has a faulty compressor by listening to a loud noise when it is turned on. If you hear this noise, it is important to have the compressor checked by a professional as soon as possible.

6. Refrigerant Gas Issues In Heat Pumps

GSHPs work in the same as your fridge but in reverse. The heat pump uses a refrigerant to absorb heat from the ground and then transfers it to your home.

Over time, the refrigerant in your heat pump will start to leak. This can happen for a number of reasons, including physical damage, corrosion, or even a manufacturing defect.

If you notice that your heat pump is not performing as well as it used to, it is important to have the refrigerant level checked by a professional. In most cases, you will need to have the refrigerant replenished or replaced.

7. Glycol Breakdown

When you have your heat pump serviced they will generally check glycol transfer fluid in systems with a water loop.

Glycol is an agent added to the water to help protect it from freezing in winter. The ground is heated and then dumped as heat at the heat pump’s evaporator via a pump run by glycol. The freezing point of the purchased heat transfer fluid is raised to minus 12°C by mixing it with water.

If you notice that your heat pump is not performing as well as it used to, it is important to have the glycol level checked by a professional.

8. High GSHP Electricity Bills

You may get high GSHP bills when folks inadvertently select the luxury hot water option on their immersion heater, which activates it every day to increase the tank’s hot water.

You can also find that your electricity bills are high if your heat pump is not properly insulated.

Also, the size of your heat pump might be wrong based on the size of your property. If this is the case, your heat pump will have to work harder to heat your home, which will use more electricity and increase your bills.

9. Stuck Reversing valve

A common problem with any heating system is a stuck reversing valve. The reversing valve is used to change the direction of the flow of refrigerant. This allows the heat pump to operate in both heating and cooling mode.

If the reversing valve becomes stuck, it can cause the heat pump to stop working altogether. In most cases, the only way to fix this problem is to replace the entire reversing valve.

10. Low Refrigerant Levels

Low refrigerant levels are one of the most common problems with heat pumps. The refrigerant is what helps to transfer heat from the ground to your home.

Over time, the refrigerant can start to leak out. This can happen for a number of reasons, including physical damage, corrosion, or even a manufacturing defect.

If you notice that your heat pump is not performing as well as it used to, it is important to have the refrigerant level checked by a professional.

11. Too Much Indoor Humidity

One of the drawbacks of utilizing a heat pump is that it can raise the humidity level in your house. Too much airflow or a unit that is too big for your home might be to blame for the high humidity levels in your home.

If you notice that your home is more humid than usual, it is important to have your heat pump checked by a professional. They may be able to adjust the settings on your heat pump to help reduce the amount of humidity in your home.

12. Fouling Of The Heat Exchanger

The accumulation and deposition of unwanted materials such as scale, suspended solids, insoluble salts, and even algae on the interior surfaces of the heat exchanger is the most frequent definition of fouling in relation to heat exchangers.

Fouling can have a major impact on the efficiency of your heat pump, as it decreases the amount of heat that is able to be transferred. If you notice that your heat pump is not performing as well as it used to, it is important to have the heat exchanger checked by a professional.

13. Radiator Too Small To Accommodate Heat Pump

If your radiators are too small to accommodate your heat pump, it can cause a number of problems. The most common problem is that the heat pump will not be able to properly heat your home.

In some cases, you may be able to replace your radiators with larger ones. To be fair, this isn’t normally a problem for newly fitted GSHP systems as the installer should size the radiators to suit the heat pump at the time of installation.

14. Weird Smells Or Noises Coming From The Equipment

Sometimes you can get a musty or mouldy smell coming from your heat pump. This is due to the build-up of bacteria and mould in the system.

If you notice any strange smells or noises coming from your heat pump, it is important to have it checked by a professional. They will be able to clean out the system and get rid of the bacteria and mould.

15. Visible Water Leaks From System Components

This is highly unusual for a GSHP system, but on the odd occasion, you might see water leaks from some of the system components.

This could be due to a number of different problems, including a faulty heat exchanger or condensation build-up as I mentioned earlier.

If you notice any water leaks, it is important to have your heat pump checked by a professional. They will be able to determine the cause of the leak and fix it.

FAQs

Do Geothermal heat pumps use refrigerants?

There are two commonly used types of fluids in GSHP systems – antifreeze (Propylene Glycol), and refrigerant (R-410a).
This is because water has a very high specific heat capacity, meaning it can store a lot of heat. It is also relatively easy to pump and doesn’t require much maintenance.
The downside to using water is that it can freeze, so the system needs to be designed carefully to prevent this from happening.

References:

WGisol, CC BY-SA 4.0, via Wikimedia Commons
About the Author

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

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