Why is my pool heat pump icing up?

Wu Kelly
5 min readJul 15, 2023

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During the winter months, some ice on your pool heat pump is common. However, when the entire unit is covered in ice, your unit will not work properly and may be at risk of damage, so you need to worry.

This article focuses on people who want to use a pool heat pump in the winter. Causes of equipment icing or freezing can include damaged circuits, frozen pools, burst pipes, etc. Ignoring a frozen unit can create major problems.

Causes of pool heat pump icing

The most common cause of pool heat pump icing is a lack of proper care and maintenance. This can lead to damage to the equipment and eventually cause it to freeze.

Here are some other possible causes of your pool heat pump freezing:

Damaged unit or system

Most heaters come with a defrost unit whose main purpose is to defrost any ice that may have settled in the unit. If the defrost unit fails, the unit will not heat the ice crystals that have frozen in the machine.

In addition, the lower temperature in the evaporator fins compared to the dew temperature in the ambient air can cause condensation to form on the surface of the evaporator fins. When the temperature is 0 degrees Celsius, the ambient air will cause the condensate to frost. Here are some other parts that, if damaged, may cause the machine to freeze.

►Refrigerator charge problem

►Damaged control board unit

►Sensor unit has problem

►Damaged evaporation coils

►Valve failure

Insufficient air flow

Once the refrigerant temperature in a pool heat pump drops below the freezing point, any moisture in the atmosphere will freeze, especially in the condenser coils and evaporator. This can happen if there is not enough airflow through the unit. Insufficient airflow can cause moisture to be trapped in the unit system, which can turn into frost during the cold season.

Chilled water

Freezing rain falls on the unit and turns to frost; once the top starts to freeze, the rest of the unit will quickly follow. Another cause of your pool heat pump freezing could be hail from the rain clogging the unit and freezing it from the inside out.

Heat pump leaks/condensation

Before jumping to conclusions, check the cause, as both issues present almost similar challenges. If the heat pump is leaking, there is a ruptured tube inside that is releasing water, and during the cold season, the released water can frost and freeze the unit.

You will need to shut off the heat pump and allow water to pass through to drain the condensate. If you are also considering fixing the air flow to the unit, this will help. There is a test one can run to determine which of these two issues is the problem.

Use a chlorine strip near the heater to test for a reaction; if there is a reaction, it indicates a heat pump leak. When there is no reaction it just means it’s condensing or raining.

Low or High Freon Pressure

Low Freon pressure is a common challenge that occurs when it is too cold outside to heat your pool. Low pressure is a sign of low temperatures and means low refrigerant, which will freeze the evaporative coils. Most heat pumps will work effectively as long as the atmospheric temperature exceeds 45F -50F.

On the other hand, high Freon pressure can occur at low flowing water pressure, which means that there is not enough water to pass through the heat exchanger for the heat transfer process. This condition is sometimes confused with a faulty valve that appears open but is closed in the pipe.

Understanding the cause of a frozen pool heat pump is the beginning of preventing or fixing the problem. Here are some techniques you can try to avoid or stop your pool heat pump from freezing.

Ways to prevent your pool heat pump from freezing

Sometimes, preventing your pool heat pump from freezing boils down to proper maintenance and upkeep. Checking your unit frequently to make sure it’s running well and replacing worn parts when problems arise can help ensure that your unit doesn’t get damaged.

In some cases, the problem may be as simple as adjusting the defrost settings to accommodate the temperature difference. Therefore, be sure to adjust all settings to accommodate the ambient temperature.

Use antifreeze.

Just as its name implies, antifreeze protectors protect your pipes and pool from freezing. The antifreeze protector is connected to your pool equipment to automatically circulate the water and activate the pool heat pump when the temperature reaches the freezing point. It acts like a robotic pool assistant, protecting your pool equipment and the pool itself.

Ensure good airflow

As mentioned above, insufficient airflow can lead to frost inside your equipment. Remember to clean your equipment regularly and remove any leaves, particles or debris that may be blocking perfect airflow.

Settling down

Often heat pumps are placed on a concrete slab, which over time settles on the slab. This can block drainage channels for melting ice and prevent good airflow, leading to ice buildup. If this is your problem, the fix is simply to move it around a little to make room for the ice to pass through as it melts.

Seal in your pool.

Sealing in your pool will help prevent it from freezing during the cooler months. Allow your pool heat pump to run for 12 hours on a regular basis to continue to reach the desired heat pump temperature above 50F. This will allow your heat pump to work properly as the temperature is favorable.

Call a technician.

If all else fails to produce results, then seeking out an experienced professional may be the best solution to fixing your frozen heat pump. It is best to choose a technician from the company you purchased the equipment from, as different equipment has different designs.

Overview

Don’t let your pool heat pump suffer the consequences of ignorance, while you can take steps to prevent it. This article provides the reader with the most common reasons why a pool heat pump may freeze and ways to avoid or fix the problem.

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Wu Kelly

Heat Pump Manufacturer-Foshan Guangteng New Energy Co., Ltd.