Heat Pump Not Defrosting – What To Do?

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The heat pump is an integral part of any HVAC system in one's household. So, if the heat pump isn't defrosting properly, it could spell trouble for you at home. But no need to worry, as we did our research and asked professionals what to do in this situation.

According to professionals, being patient is the best advice they could give. Simply put, give the heat pump's defrost system about 3 to 4 hours to defrost. If the issue is still unresolved, your best bet is to call in an HVAC technician to have a look at your heat pump.

In this article, we will discuss several reasons that cause the heat pump's defrost system to fail. What's more, we will also talk about whether there are alternative solutions one can use at home to resolve the issue. So, continue reading until the end to find out this and more.

Two heat pumps on the back of the house, Heat Pump Not Defrosting - What To Do?

How Do Heat Pump Defrost Systems Work?

There are several components that work together in order for the whole system to work. But to keep it simple, a heat pump system has a sensor that tells the machine when it's time to defrost. This sensor is can also work in tandem with your home's thermostat.

The sensor would then send out a signal to the defrost system whenever it detects ice forming. Also, most manufacturers would set a given time for the defrost system to work. That's why, sometimes, it takes a while for the defrost cycle to start.

Technician checking the heat pump

But the usual amount of time for the defrost cycle is around 10 minutes. That's why it's best to check the user manual to learn more about your particular heat pump at home and what instructions the manufacturers have given out.

Check this heat pump system on Amazon.

8 Reasons A Heat Pump Is Not Defrosting - What To Look For?

In this section, we will talk about several reasons that may be causing your heat pump's defrost system to not work properly. Bear in the mind that these are some common issues that most heat pumps face.

However, there may be other obscure reasons that result in a faulty defrost system. That's why it's always best to have an HVAC professional do the inspection.

1. Ice And Snow

During winter, extreme temperatures can cause your heat pump to malfunction and have reduced efficiency. Internal components freezing is a natural occurrence, especially if not handled immediately.

That's why it's important to remove any build-up of snow and ice that would appear on your heat pump. Be careful not to use sharp objects when doing so, as you may accidentally damage the heat pump during the cleanup process.

Below, we provided a link to an article that discusses this topic in greater detail. So, consider checking it out to find out more.

How Much Ice Is Too Much On A Heat Pump?

2. Drainage Problems

Random debris, like twigs, leaves, and dirt, can block the drainage. This prevents the heat pump from working as intended, as its fans would be unable to pull air from the outside.

Even more than this, it can cause further damage during the winter as these debris can freeze up and turn solid. So, make sure that nothing is blocking the drainage, clearing up any debris that you might find.

3. Low Refrigerant Levels

The refrigerant is key for defrosting. Without enough refrigerant, the heat pump's defrost system would either be inefficient or it won't start up at all.

Normally, you can resolve this by having an HVAC professional recharge the system or fix any leaks. Usually, the costs would be between $200 and $1,000 for both services.

4. Improper Installation

Another reason your heat pump at home is not defrosting properly is because of improper installation. It's important to note that only those with the proper experience and background should do the installation. Hire anyone else and it might cause the whole system to fall apart.

What's more, installing the heat pump in a less than ideal placement can greatly affect it as well. Heat pumps require proper airflow or else, it would work at less than half the optimal working condition. Call an HVAC professional if this is the case.

5. Bad Reversing Valve

The reversing valve is responsible for the switch between heating and cooling. So, it's safe to assume that a faulty valve would result in the machine not working properly.

If you notice both modes are not working properly, have a technician take a look. Although you can also inspect this yourself, it's best to have the professionals resolve it for you.

6. Wiring Issues

Over time, wear and tear can cause electrical issues. It can fray and cause short circuits inside the system. This would cause the system to not be able to properly relay the instructions from one another.

Have an electrician, or an HVAC professional do this job for you. It's best to let someone who has more experience in dealing with electricity handle this.

7. Faulty Sensor/Thermostat

Often, a poorly placed thermostat or a faulty sensor can cause the heat pump to not work. It can cause the defrost system to not work properly because it receives no signal from these devices.

Simply resetting them should do the trick. If not, you might need someone to have a look. In the worst case, you'll be in the market for a new thermostat or sensor.

Check this thermostat on Amazon.

8. Outdoor Fan Issue

The outdoor fan pulls in air from the outside. This then aids the system in defrosting.

The fault usually lies in the capacitor. Its main responsibility is to give the fan the extra electrical energy it needs to move. Have an electrician or an HVAC professional repair or replace this component for you.

Black heat pump mounted on a concrete slab

What To Do When Heat Pump Is Not Defrosting?

A tall double heat pump mounted on the side of a house

As mentioned earlier, the best way to resolve the issue is to give your heat pump more time. Three to four hours is what HVAC professionals recommend.

Normally, a heat pump system has no issues to speak of. So, all it really needs is some time to defrost. So, if you notice that your heat pump at home is taking a while, it's most likely to be within the normal range.

But if the heat pump still does not defrost even after four hours or more, then it's safe to assume that there's indeed an issue with the machine. Call an HVAC professional to deal with the problem for you.

Do you wish to know how to defrost a heat pump? Below, we provided a link to an article whose discussion centers on that topic. Consider checking it out to get a more in-depth answer.

How To Defrost a Heat Pump?

When The Worst Heat Pump Freeze Ups Are Likely To Occur?

A heat pump mounted near the driveway

When a heat pump freezes up is during the winter months, it's the worse-case scenario. This is especially the case when snow starts to fall.

During winter, the temperatures are low enough to freeze the outdoor coil of a heat pump. The outdoor coil's efficiency then drops, impacting the defrost mode of the heat pump.

Beyond that, the falling snow itself present and even greater issue. The outdoor fan pulls the falling snow into the system instead of letting it fall to the ground.

What ends up happening is that the heat pump would need another round of defrosting almost immediately after the first cycle ends.

This endless cycle can cause severe wear and tear on your heat pump, leading to significant damages on the machine. Replacement of parts or even the entire heat pump system is highly likely if left unchecked.

Below, we included a link to an article that discusses this topic in even more detail. It would tell you more about what you need to do when your heat pump freezes up in the winter.

Heat Pump Freezing Up In Winter; What To Do?

In Closing

Two heat pumps on the back of the house

In short, patience is the key to resolving your heat pump's issues. Giving the heat pump a few hours would usually resolve the issue. If not, it's best to call in an HVAC professional to troubleshoot the issue for you.

If you enjoyed reading through this article, consider checking the links below. They address topics that involve a heat pump not working properly. So, be sure to give these articles a read to find out more about troubleshooting your heat pump at home.

Heat Pump Not Keeping Up; What To Do?

Heat Pump Heats But Does Not Cool; What's Wrong?

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