How to Prepare Your Swimming Pool Heat Pump for Winter

As temperatures begin to fall, preparing your swimming pool heat pump for winter should be an important part of your end-of-season pool maintenance.

Whether you plan to continue heating your swimming pool throughout the cooler months or shut the system down until spring, a little preparation can help protect your heat pump, maintain its performance and make reopening your pool much easier.

Most importantly, if your swimming pool heat pump is going to be switched off during freezing weather, simply turning off the power may not be enough. Water left inside the heat pump can freeze, expand and potentially cause damage.

In this guide, the pool heating specialists at HeatPumps4Pools explain how to prepare and winterise your swimming pool heat pump correctly.

Do You Need to Winterise a Swimming Pool Heat Pump?

Whether you need to winterise your pool heat pump depends primarily on whether your swimming pool will remain operational throughout winter.

If you intend to continue swimming, your heat pump may be able to remain in operation, provided the particular model is designed to work within the temperatures you expect and is operated in accordance with the manufacturer’s instructions.

Some swimming pool heat pumps are specifically designed for extended-season or all-year operation, while others have more limited operating temperature ranges.

If you’re closing your swimming pool for winter, however, the heat pump should be properly winterised rather than simply switched off and forgotten about.

Always follow the winterisation instructions provided by the manufacturer of your particular heat pump.

1. Decide Whether You’ll Use Your Pool During Winter.

Before doing anything else, decide whether your swimming pool and heat pump will remain in use.

Keeping Your Pool Open.

If you plan to continue heating your pool, check the minimum operating temperature specified for your swimming pool heat pump.

Operating a heat pump outside its designed temperature range could affect its ability to heat effectively and may cause operational issues.

You’ll also need to continue maintaining the wider swimming pool system, including filtration and water circulation.

Closing Your Pool.

If your pool is being closed until spring, your heat pump should be shut down and winterised according to the manufacturer’s instructions.

Particular attention should be paid to removing water from areas where it could freeze.

2. Clean Around Your Swimming Pool Heat Pump.

Autumn leaves, dirt and other debris can quickly accumulate around an outdoor heat pump.

Before winter, clear away debris from the surrounding area and ensure that the heat pump’s air inlet and outlet are unobstructed.

Adequate airflow is essential for correct heat pump operation.

You can also visually inspect the evaporator for dirt and debris. If cleaning is required, follow the manufacturer’s recommendations and take particular care around the evaporator fins, as they can be delicate and easily damaged.

Keeping the area around your heat pump clear is particularly important if you plan to continue using it throughout autumn and winter.

3. Check Water Flow Through the Heat Pump.

If your swimming pool heat pump will remain operational, make sure there is sufficient water flowing through it.

Restricted water flow can reduce performance and may result in a water-flow-related error on the heat pump.

Check:

• The swimming pool filter is clean.
• Circulation pumps are operating correctly.
• Valves are in the correct positions.
• Water is flowing freely through the system.
• There are no obvious restrictions or leaks.

Your swimming pool heating and filtration systems work together, so keeping on top of general pool maintenance can make a significant difference to heat pump operation.

4. Protect Your Pool Heat Pump From Frost.

Frost protection is one of the most important parts of swimming pool heat pump winterisation.

If a heat pump is being shut down and temperatures could fall below freezing, water should not be left trapped inside the unit.

When water freezes, it expands. If this happens inside the heat exchanger or associated pipework, it can potentially cause serious damage.

The exact winterisation procedure will depend on your heat pump and installation, but it may involve:

• Switching off and electrically isolating the heat pump.
• Isolating the unit from the swimming pool circulation system.
• Disconnecting water connections where appropriate.
• Draining water from the heat exchanger.
• Draining associated pipework where required.

Always follow the manufacturer’s winterisation procedure for your particular swimming pool heat pump.

If you’re unsure how to correctly drain or winterise your heat pump, seek professional advice rather than risk leaving water trapped inside the system.

5. Don’t Just Switch Your Heat Pump Off.

One of the most important things to remember is that switching off a swimming pool heat pump doesn’t automatically make it winter-ready.

Turning off the electrical supply stops the unit from operating, but it doesn’t necessarily remove the water sitting inside it.

If that water is exposed to freezing conditions, it could freeze and expand even though the heat pump isn’t running.

For a swimming pool being closed for winter, correct draining and winterisation are therefore essential.

Off doesn’t necessarily mean winterised.

6. Inspect the Heat Pump and Installation.

Winter preparation provides a useful opportunity to inspect your entire pool heating installation.

Take a look around the heat pump and check for:

• Signs of water leaks.
• Loose pipework or fittings.
• Damaged pipes.
• Visible damage to the unit.
• Excessive dirt or debris.
• Vegetation growing too close to the heat pump.
• Anything obstructing the air inlet or outlet.

Finding a small problem at the end of the swimming season gives you an opportunity to address it before it becomes a bigger issue when you want to start heating the pool again.

7. Should You Cover a Swimming Pool Heat Pump in Winter?

It can be tempting to completely wrap an outdoor swimming pool heat pump to protect it from the weather, but this isn’t necessarily the best approach.

Swimming pool heat pumps are designed for outdoor installation, and completely wrapping a unit could trap moisture.

If you want to use a winter cover for your swimming pool heat pump, make sure it is suitable for your particular model and follow the manufacturer’s recommendations.

Most importantly, never operate a swimming pool heat pump while it is covered or when its airflow is obstructed.

If you’re continuing to use the heat pump throughout winter, the air inlet and outlet must remain clear.

8. Keep Leaves and Debris Under. Control

Preparing your heat pump shouldn’t be a one-off job at the beginning of autumn.

Leaves and other debris can continue to collect around outdoor pool equipment throughout the colder months.

If your heat pump remains operational, periodically check the area surrounding it and remove anything that could restrict airflow.

This is particularly worthwhile after storms, strong winds or periods of heavy leaf fall.

9. Plan Ahead for Restarting Your Pool Heat Pump in Spring.

Correct winterisation doesn’t just protect your heat pump during winter. It can also make restarting your swimming pool heating system in spring much easier.

Before restarting a winterised heat pump:

• Reconnect any pipework or connections that were removed.
• Check valves are correctly positioned.
• Restore water circulation
• Check the system carefully for leaks.
• Make sure the heat pump has unobstructed airflow.
• Follow the manufacturer’s start-up procedure before operating the unit.

Don’t simply switch the heat pump back on without first ensuring water is circulating correctly through the system.

Can I Run My Swimming Pool Heat Pump During Winter?

Potentially, yes.

Whether you can use a swimming pool heat pump during winter depends on the operating temperature range of the particular model, your desired pool temperature, local conditions and the overall design of your pool heating system.

Some modern inverter swimming pool heat pumps are designed to operate at low outdoor temperatures and can therefore support an extended swimming season or, in suitable applications, all-year pool heating.

However, a heat pump being technically capable of operating at a particular outdoor temperature doesn’t necessarily mean it will provide the same heating capacity or efficiency that it achieves during warmer conditions.

This is why correct heat pump sizing is particularly important when planning to heat a swimming pool during colder months.

What Happens If Water Freezes Inside a Pool Heat Pump?

Water expands when it freezes.

If water is trapped inside a heat pump’s water circuit during sub-zero temperatures, this expansion can potentially damage components such as the heat exchanger or associated pipework.

This is one reason correct winterisation is so important for swimming pool heat pumps that won’t be used during winter.

Don’t assume that switching the unit off is sufficient protection against freezing conditions.

Swimming Pool Heat Pump Winter Maintenance Checklist.

Before winter arrives, remember to:

✓ Decide whether the pool will remain operational.
This determines whether your heat pump needs to continue running or be winterised.

✓ Check the heat pump’s operating temperature range.
If you’re continuing to heat your pool, make sure your model is suitable for the expected conditions.

✓ Clear away leaves and debris.
Keep the air inlet, outlet and surrounding area unobstructed.

✓ Check your filtration and water flow.
Good circulation is essential if the heat pump remains operational.

✓ Inspect the installation.
Look for leaks, damaged pipework, loose fittings and anything unusual.

✓ Protect the system from freezing.
If you’re shutting the heat pump down, follow the manufacturer’s instructions for draining and winterisation.

✓ Don’t simply switch it off and forget about it.
Water remaining inside the heat pump may still be vulnerable to freezing.

✓ Prepare for spring.
Correct winterisation now can make restarting your swimming pool heating system much easier next season.

Expert Swimming Pool Heat Pump Advice From HeatPumps4Pools.

Swimming pool heat pumps are designed to live outdoors, but that doesn’t mean they should be ignored when temperatures start falling.

Keeping your unit clean, maintaining adequate airflow and water flow, and correctly winterising a system that won’t be used can all help protect your equipment and prepare it for the next swimming season.

At HeatPumps4Pools, swimming pool heating is our speciality.

Whether you need help choosing a new swimming pool heat pump, understanding how your existing system should operate during colder weather or preparing your pool heating system for winter, our team can provide advice based on your particular installation.

Need Help With Your Swimming Pool Heat Pump?

Don’t wait until the first frost to think about your pool heating system.

Contact the HeatPumps4Pools team for expert swimming pool heat pump advice, or explore our range of swimming pool heat pumps if you’re considering upgrading your pool heating system.

A few minutes of preparation now could save a much bigger headache when the temperatures fall, and help ensure your pool heating system is ready when swimming season returns.