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Why Does My Air Source Heat Pump Freeze in Winter?

Why Does My Air Source Heat Pump Freeze in Winter?

May 31,2022
If the temperature in your area is extremely cold (below 32℉ or 0℃), it is normal for the heat pump to run almost continuously.

This is largely due to the defrost function of your pump - we will discuss this in detail in this article. But in short, the defrost cycle helps avoid a lot of ice buildup on the air source heat pump.

If your heat pump is struggling with icing, the system may not be operating efficiently and there is a bigger problem at hand.

Here are some factors that contribute to icing:

The refrigerant level of your air source heat pump is low.

Time to replace the air filter.

One (or more) components inside the heat pump unit have failed. You need to investigate thermostats, temperature sensors, and refrigerant metering devices.

Ice blocks the fan blades or coils of the blower.

The outdoor blower motor has failed.

The diverter valve is stuck.

While these are all factors that should be cause for reasonable concern, it's important to note the following: If you live in an area where temperatures can drop below freezing, you may find your air source heat pump frozen. Please don't panic. This is perfectly normal during long periods of cold weather.

It's perfectly normal for frost to build up on the coils when your heat pump is trying to heat your home.

But why is this so?

When the pump generates heat, the refrigerant turns into a gas and then condenses when it comes into contact with the outdoor coil. So in winter, it makes sense that this condensation freezes. This is where the defrost function of the heat pump comes into play.

Air source heat pump defrost cycle

The defrost function of the heat pump is essential in cooler climates. This feature prevents the pump from freezing completely. But to save your energy, it doesn't run continuously, but only when necessary.

So how does it know when to run?

Each unit has a temperature sensor responsible for triggering this function. But don't worry about this process is too energy-intensive. These cycles typically only last 10-15 minutes at a time, depending on external conditions.

When can icing on a heat pump be a problem?

What you want to pay attention to here is the defrosting ability of the heat pump. If your device is not defrosted properly or not fast enough, damage and therefore failure can occur.

This is problematic for a number of reasons:

A clogged coil (from ice) cannot effectively draw cold air from your home.

Your system heat output capacity will drop dramatically.

Continuing to run an air source heat pump when air cannot pass between the fins is detrimental.

A heavily icing heat pump can damage fan blades, affect outdoor coils, cause refrigerant to leak, and damage other components.

Signs of a problem to watch out for

If you're having any of the following issues with your air source heat pump, it's time to get the professionals involved:

You find your heat pump is freezing

It has been frozen for a long time

Both the top and inner coils of the unit are covered with ice.

The defrost cycle function is not activated.

Air is not drawn into the fins of the device.

If you are looking for an affordable way to heat your home, then an air source heat pump is the way to go.

While these pumps aren't too heavy for your wallet, they also serve you and the planet by:

Reduced electricity consumption - Heat pumps operate very efficiently, around 400%. For every unit of electricity you use, you generate 4 units of heat energy. Traditional electric heaters are up to 100% efficient, so you need 75% less electricity to heat your home. The electricity that may be produced by a power station that burns fossil fuels.

Maintenance - Air source heat pumps require minimal maintenance

Zero emissions - The heat pump process does not release any local harmful emissions.

Refrigerant fluids - Historically, refrigerant fluids have had a bad reputation. Fortunately, several recent alternatives have a much lower global warming potential (GWP), if not none.

Lower carbon impact potential - They produce less carbon dioxide than other more traditional heating methods.

If you still have questions or want to buy an air source heat pump, please contact us.

SUOHER is a professional heat pump manufacturer and supplier, we have a team with rich experience in heat pump design, processing, quality control, and controller function development. Our target is global, including Europe, South America, South Africa, and Asia. Our team has had extensive experience in the heat pump field since 2006.

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