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Things To Check When Your Heat Pump’s Not Working Right

Note: This post may contain affiliate links. This means that at no cost to you, we may receive a small commission for made purchases.

A heat pump is an appliance that uses electricity to move heat from outdoors into your house.

If your heat pump isn’t working properly, it could cause damage to your home.

Your heat pump should be checked by a professional before winter begins, but here are some things you can check yourself if you find you have any problems.

Why Is My Heat Pump Not Working?

Heat pumps work by using electricity to move heat from inside your house to the outside or vice versa.

You’ll need to know what kind of heat pump system you have before you begin troubleshooting.


Heat pumps use electricity to move heat from inside your house to outside.

When the heat pump isn’t working, check the thermostat first. Make sure it’s set correctly. 

Check the wiring around the unit. Is the power cord connected properly?

Does the unit have enough refrigerant? Are the air filters clean? Do you need more insulation?

Let’s go into more detail about troubleshooting a malfunctioning heat pump. 

Check The Thermostat

When you face a heat pump that doesn’t work, check the thermostat setting first.

If you want it to heat and it’s set to cool, you’ll likely get cold air coming from the vents.

The opposite happens if you want it cooling and you’re getting hot air.

Another item on this list of heat pump problems could be a problem with the thermometer.

If it seems like it’s working but you can’t seem to get the temperatures in your house to where you want them, the thermostat might need to be recalibrated.

Things can get out of sync if you bumped into it, and the thermostat isn’t level anymore.

This can cause the thermometer it uses for temperature readings to be off.

Another possible cause is dust and dirt in the unit. Try removing the faceplate and cleaning any dust or dirt you can see on the contacts.

Check The Power

A circuit breaker must be checked first before calling for help. The outdoor and indoor units should be on different breakers.

The outdoor unit has a power disconnect switch. 

If the switch is turned off or broken, the problem is most likely caused by a blown fuse.

You may need to contact an electrician to repair this issue.

Check The Air Filters

Air filters remove dust, allergens, and particles from your house.

If they get too dusty or clogged, they may stop working properly. If it gets bad, you may need to replace them.

Air filters should be checked regularly to ensure they are clean enough to work properly.

Dirty filters can cause heating and cooling systems to run inefficiently. A $5-10 filter can help lower your energy bills.

Check The Outdoor Unit

You should always check the temperature of your air conditioner before calling an HVAC company.

If you notice frost or ice on the coil, it means the unit is not transferring heat effectively.

Check the filter and make sure it’s not clogged.

Clean off the coils and replace them if necessary. Make sure the compressor is running smoothly.

Check Refrigerant Levels

Check Refrigerant Levels

A frozen coil could mean that there is a leak in the unit. The technician can check for leaks and fix them if needed.

Check The Reversing Valve

Heat pumps are used to cool homes during hot summer days.

A heat pump uses electricity to run an electric fan inside the house, which blows air over coils that produce cold.

When the temperature drops below a certain point, the fan stops blowing air over the coils, and instead sends the cooled air back into the house.

To make sure the heat pump works properly, check if the reversing valve is working correctly.

Check Your Ductwork

Leaky ducts could mean you’re losing money because you’re not using the full capacity of your heater or cooler.

You should check your ducts to make sure they aren’t leaking air.

It could also mean that the ducts have been damaged by a tree branch falling through the roof.

Check For Water Damage

If water damage is found in your home, call a professional immediately.

If you don’t act quickly, mold will start growing. Mold can cause health issues and even lead to structural damage.

Common Problems

Heat Pump Running Constantly

The most likely reason why your heat pump is always running is because of dirty filters.

Cleaning out the filter regularly will help save money on electricity bills.

You should try to avoid setting your thermostat at 78 degrees Fahrenheit because it might be too cold for comfort.

Lowering the temperature by 2 degrees may help you get more comfortable.

You should adjust your thermostat to 68F during winter.

If you are having difficulty adjusting to this temperature, then add more clothes.

This isn’t enough either? Lower the temperature by a few degrees and gradually increase the temperature again.

If you’re comfortable at 72F, then lower the temperature even more.

Air filters must be cleaned regularly. You can check if they’re dirty by holding them up to a light source.

If you can see through them, they’re fine. If not, you need to wash them with soap and let them air dry.

Outdoor Unit Is Frozen

In winter, you should clean your heat pump every week. You should also check the temperature gauge before leaving your house.

If the temperature gauge shows -5 degrees or below, then you should turn off your heat pump.

Outdoor units are blocked by snow. Clearing snow from the area around them helps prevent further accumulation of ice.

Using a hose to spray water on the ice melts it slowly.

Don’t use a sharp tool to remove the ice because you’ll damage the coil. Spray water instead.

If your outdoor fan is defective you need to contact a professional to fix it.

Low refrigerant means that the compressor isn’t working properly. Heat pumps won’t work without refrigerant.

A refrigerant leak could cause damage to the system or even burn up the compressor.

Don’t try to fix it yourself. Always call a qualified technician.

If the unit is not defrosting, check the reversing valve responsible for switching the heat pump from heat mode into air conditioning mode.

If the reversing valve breaks, the heat pump doesn’t defrost. Contact a seasoned HVAC professional.

Your unit could also have a faulty defrost timer.

Defrost timers are designed to turn on periodically, but if your defrost timer is malfunctioning, you may be experiencing problems with your heat pump.

A heating and cooling expert can help diagnose the problem.

Clogged filters cause dirty air to circulate around the coils. Dirty coils prevent heat from transferring to the air.

This causes the coils to get too cold, which then freezes the coils. The coils cannot lose heat to air anymore, so they stay frozen.

This leads to more freezing, which makes the coils even colder.

Eventually, this leads to an entire layer of ice building up on the coils.

This blocks the airflow, making the coil even colder.

This cycle continues until the coils freeze completely, or until the compressor stops working.

Also, water sometimes drips on your outdoor unit in winter. You need to defrost the unit first before you repair the leak.

Indoor Air Handler Not Working

If your indoor air handler is not working properly, it is because there is something wrong with the outdoor unit.

You should contact an HVAC technician to fix this problem.

A trip circuit breaker means there is something wrong with your air conditioning system.

For instance, a bad wiring connection. Loose or frayed wires prevent power from reaching the indoor unit.

Or, a blown blower motor. The worst case scenario is that you have a blown blower motor.

The heat pump cannot circulate air throughout your home in this case. Contact an HVAC professional.

Heat Pump Not Heating

Your heat pump stopped working because there was a power outage or something else happened.

You should check whether the thermostat is set properly. Also, make sure that the heat pump is plugged into an electrical outlet.

Maybe you’ve set the thermostat incorrectly. Check if you’ve set it to cooling mode.

If you haven’t, then check if your fan is working properly. If your fan isn’t working correctly, turn off the fan and set the system to heat.

Incorrectly calibrated thermostats may lead to problems with heating. Dirty air filters may cause heating issues.

Professionals can replace dirty air filters or calibrate them correctly.

Air filters should be washed regularly to prevent dust and other particles from building up inside.

Dirty air filters may cause your furnace to stop working properly. Cleaning the filters yourself is easy and inexpensive.

You can do it by hand or use an automatic filter washer.

Low refrigerant means you need to replace your compressor. Cleaning the outside unit will help get rid of ice buildup.

Leaks are a common problem in central heating systems.

To fix this issue, you need to call a professional who knows how to detect leaks and repair them.

Heat Pump Not Cooling

Your heat pump may be malfunctioning because of a faulty thermostat (see also ‘Is A Heat Pump Thermostat Needed?’).

To fix this problem, check if your thermostat is working properly.

If your heat pump works fine in heating mode but not in cooling mode, then you may have a faulty reversing valve (or a defective compressor).

You should contact a professional to repair this problem.

Your refrigerant level must be checked regularly. A low refrigerant level can cause your heat pump to work poorly.

Call an expert to check your system.

Cleaning the filter regularly helps the system work better. Debris blocks the unit, making it less effective.

Cleaning the area around the unit prevents blockage. Dirty coils prevent heat transfer between the refrigerants and the air.

Cleaning them helps improve efficiency. Ice buildup on coils damages the delicate fins. Don’t try to physically remove the icicles.

Your heat pump (see also ‘How Big Is A Heating Pump And What Size Do I Need?‘) must be sized correctly. You should call an expert if you think your unit might be too small.

Heat Pump Doesn’t Switch from Heat to Cool Or Vice Versa

Your reversing valve may need replacing if you’re having problems switching modes.

Contact an HVAC professional to check out your reversing valve.

Heat Pump Is Short Cycling

A short-cycling heat pump may be caused by improper sizing.

Your heat pump should be sized appropriately for your home.

Call an HVAC technician if you think your heat pump is too big or too small.

Overheating systems shut off when the temperature gets too high.

Dirty air filters prevent airflow and cause overheating. Refrigerant leaks make your system unable to cool properly.

Only a professional can diagnose and repair these problems.

Incorrectly calibrated thermostats cause heat pumps to work harder than necessary.

Recalibration is recommended if the thermostat isn’t working properly. Placing the thermostat in the correct location is also important.

When you set the temperature of your house, you should know what temperature you want.

You shouldn’t let the heat pump run longer than necessary.

And when setting the temperature of your house you should consider the location of your thermostat.

Unit Is Leaking Liquid

There are many ways to prevent leaks. You should check your heat pump regularly to make sure it is working properly.

If you notice mold growing around your heat pump, this might mean that there is a leak. Don’t ignore any signs of leakage.

You should check your refrigerant levels regularly. When you do, make sure to replace them before they get too low.

If you notice leaks, you should fix them right away.

A clogged drain line can cause flooding inside your house. To prevent this, you should clean out the drain (see also ‘How To Clean The Drains In Your Home‘) line regularly.

Weird Smells

Weird Smells

Your sense of smell is one tool to check if there is something wrong and if you need heat pump troubleshooting.

Mold growth inside your heat pump or around the walls could be an issue. Mold in air duct systems can cause problems as well.

Turn off the heat pump until you can get help from professionals.

If there is a significant amount of mold, call a professional to do the job right.

Animals crawl into homes and die. You should check your air conditioner for dead animals.

A burning smell could mean that something is wrong with your air conditioning unit.

You should turn off the power to the unit and call an HVAC technician right away.

Heat pumps are versatile appliances that provide heating and cooling services. These units are prone to occasional problems.

Heat Pump Making Unusual Noises

Strange noises coming from your heat pumps are usually caused by an issue with the unit.

Banging, screeching, rattle, buzzing, grinding, and gurgling are common signs of a malfunctioning heat pump.

Loud sounds and extended sounds indicate a serious problem.


In some cases, like when hearing unusual noises coming from your heating system, you need to contact an HVAC technician right away.

For other issues, such as having problems with your air conditioner, there are several simple steps you can take to fix them yourself.

However, if these methods fail, or you don’t feel comfortable doing them yourself, an HVAC technician is always the safest option to help your heater get back up and running again.

author avatar
Anthony Barnes
Anthony Barnes is the founder of Water Heater Hub and a second-generation plumber by profession. Before developing Water Heater Hub, Anthony Barnes was a full-time plumber, and he has undertaken a wide variety of projects over the decades. As a second-generation plumber, it was easy for Anthony to get used to the technicalities of all from a tender age


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