Heat Pump Condenser Maintenance Tips, Problems and Repair Tips

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If there’s something essential for the well-being and correct functioning of a heat pump unit, it is the condenser. Without the proper conditioning, your heat pump can start having many problems, including total motor failure, low energy deficiency, bad air quality, and more. Luckily for you, frequent heat pump condenser maintenance is an easy way to prevent problems.

Here we go over the benefits a well-preserved condenser offers, the problems that can occur when it isn’t, and a short guide on how to take care of your heat pump condenser.

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Condensing unitCondensing unit
photo: Ducane

What is a condenser and how does it work

A heat pump condenser, also known as the “outdoor coil”, together with the evaporator, is the heat exchanger, that consists of the condenser coil (pipes) and fins, through which the refrigerant flows. The pipes are usually made of copper and fins from aluminum but can be from aluminum as well. This is where the condensation occurs, and where the pressurized refrigerant changes its state from a gas to a liquid.

During this process, the heat is removed from the refrigerant and dispensed to the outdoors. This is a cooling mode. In the heating mode, the flow of the refrigerant changes, thanks to the reversing valve, and the condenser coil extracts the heat from the air, becoming actually the evaporator. So, the indoor and outdoor coils can function either as the evaporator or condenser, depending on the mode.

The condenser or more accurate condenser cabinet is located outside the house. The cabinet contains the condenser coil, a compressor and a fan, including controls, valves, and sensors. The functionality of the outdoor components is vital to the performance and efficiency of your HVAC system. And because it is located outside, it is exposed to elements non-stop; hot, cold, frost, rain, debris… And that is why it has to be maintained regularly.

Tips for the best unit location

Condensing units are mostly installed outside. Why? 

When installed outside, a condenser unit is able to exchange the heat with the surrounding air. And due to an abundance of fresh air, the efficiency is high. As soon as you put the unit in the confined space, such as a garage, with a limited supply of air, the efficiency drops. During the summer, the room air gets hotter, increasing the temperature of the surrounding too – that is not good. In winter, as the heat is taken from the air, the room temperature gets lower, making the place cold and uncomfortable.

So the best place for the installation of the outdoor unit is where there is an abundance of air, a good air flow, away from direct sun exposure, bushes, trees and anything that can affect the normal operation.

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Benefits of a cleaned and well performing condenser

How important is to clean the condenser coils we will see in the statement from the US Department of Energy (DOE) “a dirty condenser coil can increase compressor energy consumption by 30%”.

Keeping the condenser in a good state offers several benefits you wouldn’t receive otherwise. Among them you’ll find:

Better energy efficiency

The airflow inside a condenser tends to get clogged when there’s too much dirt and debris inside, so the system has to run longer and harder, putting more stress on the expensive compressor. But when it’s clean, the air flows freely through the coils and promotes a much better energy efficiency that’s eventually translated into lower energy bills.

Better performance

Along the efficiency, by cleaning the condenser you’ll also get excellent performance from the device. It will heat up or cool down faster, making it more convenient to use.

Better lifespan

Maintaining the condenser clean also promotes a longer lifespan of the heat pump. Doing bi-annual cleanings (at least) will be enough to keep the device working correctly and promoting better durability.

Better air quality

There’s no mistake, a dirty heat pump delivers dirty air. To keep your indoor air quality healthy, doing constant maintenance will be your best choice.

Inside of the condenser unit

Condenser Coils

These coils are the ones withstanding the pressure from the refrigerator, up to 400 PSI when the weather is warm. This part should always be clean, so the heat transfer is more efficient without any interference.

Condenser fan

Then you have the fan, the responsible for circulating air through the condenser coil. It makes it easier for the heat to travel around. When the fan does not work correctly, either because it is broken or because it is dirty, the air won’t travel freely and will reduce the airflow inside. With little airflow, the condenser won’t work as efficiently.

Condenser controllers

These are the electronic parts related to the condenser, sometimes known as just sensors. Different types of condensers have different kinds of controllers, but in each one of them, they have the same purpose: giving orders to the condenser. These controllers sometimes also work as overheating protectors, and sometimes help the condenser to work more efficiently.

Common issues with heat pump condensers

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Condensers tend to have problems as any other component that can eventually end up in a deficient or broken heat pump. Dirty coils often lead to premature system failure as the components wear out faster. Here we list and explain each one of them:

Fan motor failure

As we said before, the condenser fan is one of the important parts of a condenser, and it can fail due to a hot day and extreme temperatures, for example. This makes the high-pressure trips or compressor to overload and shut down. A compressor that shuts down will eventually shut down the entire heat pump, which ultimately means you won’t receive any type of response from the device.

To fix it, you will have to know first the reason why the fan stopped. The first reason can be because there’s too much debris or dirt inside the condenser which made the fan to overheat and shut down automatically, due to an overload. Otherwise, it could be that the fan just broke, due to longevity or by clogging of the foreign objects.

Other reasons for the condenser fan to stop can be the electronic circuit or controllers that broke. It could also be the compressor contactor which is not sending a signal to the condenser to work. Or just any other electrical part related to the condenser.

To any of these, it is recommended to use electricity protection, or call a professional instead. But if the fan itself is broken or with any problem, it is always better to replace it.


A condenser normally produces hot air, pouring it around the heat pump and towards the surroundings. But when the heat pump is enclosed or too tight in a non-aerated place, it’s very likely that it will fall short to cool down when needed. This, eventually, causes the condenser to overheat and ultimately shut down.

This mostly happens when the device is dirty, but can also occur because the heat pump is located in the wrong place. Other reasons can be damaged controllers or sensors. Whatever the reason, it is always better to call a professional to check it.

Otherwise, you can try to move the heat pump yourself to a place where it receives enough ventilation. Outdoors are always great choices, especially in gardens of patios where the heat pump can receive more air. This not only helps them to prevent overheating but to extend their lifespan too.

Energy deficiency

Having bad energy efficiency is another problem most heat pump condensers can have. This mostly happens when the coils are dirty. As you know already, cleaning them twice or thrice per year is one of the best ways to maintain the product working correctly.

A deficient condenser demands up to 60% more energy than a condenser that’s working correctly and provides up to 40% less heating capacity. That’s why it is so important to keep them neat so you can make them work correctly and avoid overcharged bills.

Dirty air quality

Sometimes, a heat pump may start to exert dirty air from its console. Usually, this happens when the condenser coils are too greasy or dusty, and the fan only sprays dirt out. Eventually, this makes the air quality inside the house very uncomfortable and sometimes even unsafe. That is why cleaning the condenser is always necessary.

Freezing up problem

Heat pump condenser could develop frost or ice. This is often normal. When it happens, the heat pump starts the cooling mode so the hot refrigerant can move through the coils and melt the ice. This is a defrosting mode. And when the process is over, the heat pump goes back to a normal mode before defrosting.

There are, of course, other reasons why your heat pump is freezing up:

  • Your heat pump is low on a refrigerant
  • Defrost controls failure
  • Malfunctioning defrost thermostat
  • Issues with the outdoor fan motor
  • Issues with the reversing valve
  • Dirty filter, air vents, and coil

How to maintain a heat pump condenser

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If you want to avoid any of the previous problems, we know exactly what you should do: do maintenance to the heat pump condenser every six months (at least). Here’s how:

Turn off the power. Before meddling with anything related to the heat pump, including the condenser, make sure to turn it off completely. To do this, just go to the shutoff box, and turn the breaker to the off position.

Cleaning the condenser area. Now it is time to start cleaning. But this is not directly cleaning the condenser but everything around it. Take anything, including equipment and covers from the device, clear out the area from debris and nearby vegetation, and make sure that the clearance of 2-3 feet from the condenser sides and edges is provided.

Remove the outer piece. Remove the outer piece or shell. It is the one that protects the condenser from the outside. After removing it, you can clean it too with a soft-bristle brush, a vacuum, or anything similar.

Unscrew the top grille. Then after removing the outer piece, you need to unscrew the top grille. A condenser fan and other electrical connections are attached to the grille. Be careful with the electrical connections, and put all the wires to the side before taking the fan out to avoid any disconnection or broken wire. 

Spray with a hose. Whether it is a pressurized hose or garden hose, make sure the pressure is slight and soft, but enough to take most of the dirt and debris away. Here you will aim mostly to the condenser coil and prevent the electrical connections and electronic parts from getting wet. You may also spray a cleaning solution (especial for coils) and use the hose once again to get rid of the dirt even more effectively.

Try to aim to the condenser fins as well. You can spray them with the solution too. If any of them bends, you can fix them later without any issues. Then, just leave the heat pump to dry for a few minutes.

Put the elements back together. After letting the condenser part of the heat pump dry, you can now put it back together. Remember to be careful when putting the top grille and fan back again, taking into consideration the wires and electric connections inside the heat pump. If you need to bend any fins back to original form, you can use a fin comb. It is the only way to fix them without damaging the device. If the fins are not straightened the airflow will reduce so as the efficiency.

Turn on the heat pump. Now that you’ve cleaned the condenser and put it back together, it is time to let it work to see how it does. Go to the breaker and turn it ON. Make sure to adjust the thermostat if needed. Then wait to see how the heat pump works for a few minutes or hours. If you sense any irregular noise, you can turn it off and revise. Otherwise, you’ve successfully cleaned your heat pump condenser.

Note: When doing maintenance keep in mind that there is a high voltage inside the condenser cabinet.


With the previous guide, you’ll be able to successfully take care of your product for years, sometimes without the need of a professional. But if you think this is too much work or too dangerous, calling an expert is always the best choice.

And remember, proper and regular maintenance leads to better efficiency, lower energy bills, fewer repairs, and longer lifespan.

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