Troubleshooting Heat Pumps | Common Problems and Solutions (2022)

A guide and tips for troubleshooting heat pumps fast and easy. Check out this repair guide and learn how to deal with the most popular water heater heat pumps in North America: AO Smith, Bradford White, Rheem, State, Kenmore, Reliance, American, GE, and others.

The article deals with the leading causes of heat pump failure, symptoms, error codes, and easy and safe repair recommendations.

Troubleshooting Heat Pumps | Common Problems and Solutions (1)

We will assume that the water heater heat pump, before malfunction, was correctly installed - per codes and manufacturer's instructions. This includes an adequately selected room for the unit, also that the electrical and water connections are in place, so as the air filter and condensate lines, and the tank is filled with water.

The first step in diagnosing the problem and troubleshooting is to disconnect the unit for some time simply (the time depends on the model), resume the power, and determine if the error code is still present or not. If, after resuming the power, an error code is still ON, read further, and find the instructions on how to repair the unit.

To fix the problem fast and correctly, it is good to know the main heat pump parts and what's considered a regular operation.

For example, the average operating temperature of the heat pump is between 32 F and 150 F. All heat pumps are equipped with an electric fan and compressor, so it is normal to hear some noise, but not the abnormal sound.

Some noises can also be heard during the metal part contraction (cooling) and expansion (heating).

Common heat pump problems and solutions

For any issues related to the heat pump, the recommendation is to contact a licensed technician, but if you are planning to deal with the problem, here are the most common issues with the instructions on how to fix them:

  • The surrounding air gets colder
  • Water is dripping
  • No hot water / not enough supply of hot water to the shower/faucets
  • Water is too hot
  • Noise
  • TPR valve – noise and water dripping
  • Rotten egg odor
  • Discolored water
  • A problem with the compressor
  • High operating costs

Problem: Surrounding air is getting cooler


(Video) How To Fix Common Problems You May Have With Your Heat Pump

When the heat pump operates, the room air gets cooler… and that is normal. For the correct and efficient operation, the utility room where the unit is installed should have a recommended size, proper clearances around the unit, and vented correctly, so plenty of air is coming in and through the heat pump.

The heat pump uses the warm air for water heating while releasing the air, which is colder than the surrounding. One way to provide more air for the normal operation is to install the louvered door so that the air can get in from the adjacent room.

Problem: Water is dripping


If the water is dripping down the outside of the water heater, the water connections should be inspected for any loose joints or the heater's condensate drain, as it might be dirty and clogged.

For example, if the water leaks around the elements (a gasket or threads), re-seal or replace the gasket. The best solution for these problems is regular maintenance and unit cleaning.

During the water heater installation, a suitable drain pan should be installed under the unit to catch the condensate or leaky water, and piped to the appropriate drain. Since the leak can damage surrounding objects, installing an automatic leak detector with the shutoff device is recommended.

Problem: No hot water and not enough hot water


This is what needs to be checked and fixed:

The water temperature on the thermostat might be set too low – increase it if required.

If the unit is in Vacation mode – turn it off.

If the temperature is above the maximum or below the minimum recommended in some heating modes, the heat pump won't operate.

If the water heater hasn't been used for two weeks or more, the hydrogen gas can accumulate inside the tank – which is very flammable. Before running any of the electrical devices, open the hot water tap for several minutes.

(Video) Heat Pump Reversing Valve Troubleshooting Tips (Switchover Valve)

Check the air filter, and if it is dirty, clean or replace the filter.

When the demand for hot water is high, a heat pump cannot recover fast enough, so waiting for the full or partial recovery is the only option. Sometimes it is needed to change the heating mode due to the higher demand and therefore make the pump more efficient. If the water heater runs out of hot water quickly due to higher demand, the issue might be with the undersized water heater.

Check for the sediment or mineral build-up in the heater's tank or on heating elements – the limescale buildup reduces the heat transfer from the heat source to water. Draining and flushing is usually the best option. Water softeners are useful as prevention.

As the unit operates efficiently only in the suggested air temperature range, so when the air gets colder, the unit cannot heat the water to the desired temperature.

The incoming water is way too cold.

During the wintertime, the hot water loses the heat rapidly through the water pipes, so proper pipe insulation is required. The same problem is if the pipe is too long.

If the unit doesn't work, check the power, fuse, circuit breaker, TCO (manual reset limit), or ECO, requiring resetting. Also, check for the non-functioning temperature sensor – perform the resistance test and replace it if defective. Replace the heating element if burned out.

If the mixing valve is installed, check if it is malfunctioning. Also, make sure water connections are not reversed – incoming cold water gets into the hot water pipe, and outgoing hot gets into the cold side.

- Find Plumbers In Your Area -

Get FREE Quotes!

(Video) Very Common HVAC Heat Pump Package Unit Problem

Problem: Water is too hot


The thermostat might be set too high or not snug against the tank. A broken thermostat or shorted heating element can also result in extremely high water temperatures. If the electronic control is malfunctioning – the best is to call a technician. To prevent hot water scald, it is recommended to install a thermostatic mixing valve at each faucet.

Problem: The heat pump is noisy


As said before, some noise from a fan and compressor is normal, but if there is a rumbling noise, then the problem is with the mineral or sediment buildup on the heating elements. The elements have to be cleaned or replaced. The noises such as crackling, gurgling, or popping are usually related to scale or lime buildup, while the pounding sound can be reduced by installing the water hammer arrestor.

Problem: Temperature and pressure relief valve makes a popping sound and is dripping


A TPR valve is a safety element that should open only if there is an excessive pressure buildup within the closed heating system. It might also leak if the debris is stacked inside the valve. During the regular operation, the valve should not leak at all. The thermal expansion is kept under control with the installed thermal expansion tank.

To limit the water pressure inside the house plumbing, it is beneficial to install the pressure reducing valve - PRV. It should be installed on the cold water supply line to keep the pressure from 50 to 60 psi.

Problem: Hot water has a bad smell – the smell of a rotten egg


Due to the high sulfate content in water supplies (usually from a well) and its reaction with the anode rod (especially magnesium type), hot water might have rotten egg odor. One solution is to replace the anode with the kind that is less prone to this reaction (aluminum) or chlorinate the heater thoroughly.

Problem: Discolored water


If milky water is seen, the aerated faucets should be installed to eliminate the buildup gases inside the heating system.

Checking the anode rod regularly or switching to a powered anode can prevent corrosion (that makes the water look muddy or brown), as the metal tank is always protected with the effective element, which doesn't deteriorate over time.

(Video) Common Issues with Geothermal Heat Pumps Part 2

Problem: The compressor is not operating


Replace the broken compressor or check if there is a refrigerant leak. In the case of the AO Smith heat pump, check the run capacitor and look for any damages to the housing. Measure the resistance – if it is indefinite, the element has to be replaced.

Problem: High operating costs


The first things that need to be checked are the set temperature - which might be high, inefficient heating mode, and dirty air filter. Also, if the surrounding air temperature is not in the recommending range, the compressor might have trouble operating correctly.

The above problems are problems found on most of the heat pumps for residential use, but there are many more, of course. Due to the advanced electronics followed by the diagnostic system and small display screen found in almost every new unit, the error codes appear when the problem occurs – making problem diagnosing easy.

For example, an American heat pump uses the error codes such as E20, E21… Bradford White and GE heat pumps use the error codes such as F1, F2… F15, followed by the beeping sound - and each code means something; a faulty heating element, dirty air filter, compressor or air failure, sensor malfunctioning…

Every user manual contains the troubleshooting heat pumps guide with a list of the most common diagnostic codes.


  • American heat pumps (hybrids) review
  • AO Smith heat pumps review
  • Kenmore heat pumps review
  • Reliance heat pumps review
  • GE GeoSpring hybrids review
  • GE GeoSpring hybrid repair
  • Rheem hybrids review
  • State hybrids review
  • Most efficient hybrids
  • Troubleshooting heat pumps
  • Hybrid vs. solar water heater

Leave a Comment


What are common problems with heat pumps? ›

Heat Pump Failure: 5 Common Reasons for Heat Pump Malfunction
  • Heat Pump Does Not Run. ...
  • Does Not Heat or Cool Right. ...
  • Heat Pump Blower Does Not Work Or It Freezes Up and Trips Breaker. ...
  • Heat Pump Cycles Incorrectly. ...
  • Most Common Heat Pump Problem – Weird Noises.
29 Jul 2019

What would cause a heat pump to stop working? ›

A clogged air filter is a common cause behind a heat pump not working, as the system doesn't receive adequate airflow due to this obstruction. The system often overheats and shuts down, leaving you without cooling. Or, not enough cooling makes it into your home due to the restriction.

How do I reset my heat pump? ›

Reset the system by turning it off with the thermostat or breaker if your unit has a safety device locking it out. Wait 60 seconds and turn it back on. It may take up to 10 minutes for the outdoor unit to start.

How do you diagnose a bad heat pump? ›

How Can You Tell If Your Heat Pump Isn't Working As Well As It...
  1. Heat Pump Ices Up in Winter. ...
  2. Heat Pump Ices Up in Summer. ...
  3. Heat Pump Constantly Cycles On and Off. ...
  4. Blower Has Stopped Working. ...
  5. The Unit Is Noisy. ...
  6. Your Heat Pump Performs Poorly and Utility Bills Are Going Up.
10 May 2018

What temperature should heat pump be set at? ›

According to the Department of Energy, 68°F is the sweet spot that balances comfort and energy efficiency during the fall and winter months. When your home is occupied and when family members are awake, a heat pump setting of 68°F keeps the living areas reasonably warm.

How do I know if my heat pump is low on refrigerant? ›

Note the following signs that can signal that your heat pump is low on refrigerant: leaking, icing, and inefficient performance.
  1. Leaking Heat Pump. Even though a heat pump uses refrigerant to cool or heat a home, the refrigerant doesn't dissipate during regular operation. ...
  2. Icing. ...
  3. Inefficient Performance.
15 Oct 2016

Where is the fuse located on a heat pump? ›

How To Replace a Fuse on a Furnace or AC Air Handler Control Board

Why is my heat not turning on? ›

If your heating system will not turn on, the first thing you should do is check the thermostat. The thermostat's battery may have gone bad, causing it to power off. If your thermostat is hardwired, a power surge, brownout, or brief power outage may have caused the thermostat to lose its settings.

Why is my outside heat pump unit not turning on? ›

One of the most common problems is blown fuses or flipped circuit breakers. If your unit is not working, make sure to check your fuses and circuit breakers. It could be as easy as a flip of a switch.

Do all heat pumps have a reset button? ›

A lot of heat pumps don't have manual reset buttons. This might be done to prevent the homeowners from pushing the red button too often (as this, in a lot of cases, won't fix the problem).

Do heat pumps have reset switches? ›

Press the Heat Pump's Reset Button or Power Switch

Begin by turning the power off to the heat pump. You will need to reset both units by pressing the buttons or flipping the switches. If your heat pump does not have a reset button, it will have a power switch.

How long does it take a heat pump to reset? ›

How Much Time Does it Take for a Heat Pump to Reset? You can reset the unit by turning it off with the thermostat or circuit breaker. After some time, turn it on again. It can take up to 15 minutes for the outdoor system to restart.

How do you test a heat pump compressor? ›

How to Check for Bad Compressor - YouTube

How do you unclog a heat pump? ›

If you want to try to fix it yourself, all you need to do is turn the heat pump off, take apart the front cover, and unclog the drain using a towel or dry vacuum. Once it's unclogged, pour a little bit of distilled white vinegar in to help kill algae and fungi and eliminate bad odor.

How do you know when you need a new heat pump? ›

Your heat pump will let you know with these five signs.
5 Signs Your Heat Pump Needs To Be Replaced
  • It Needs Constant Repairs. ...
  • It's Older Than 10 Years. ...
  • Higher Energy Bills. ...
  • Safety Issues. ...
  • Unusual Noises.
13 Apr 2022

Should heat pump fan be on auto or on? ›

Keeping your fan on AUTO is the most energy-efficient option. The fan only runs when the system is on and not continuously. There is better dehumidification in your home during the summer months. When your fan is set to AUTO, moisture from cold cooling coils can drip and be drained outside.

What outside temperature is too cold for heat pump? ›

Heat pumps do not operate as efficiently when temperatures drop to between 25 and 40 degrees Fahrenheit for most systems. A heat pump works best when the temperature is above 40. Once outdoor temperatures drop to 40 degrees, heat pumps start losing efficiency, and they consume more energy to do their jobs.

Do heat pumps work below 20 degrees? ›

Do heat pumps work below 20 degrees? Yes, air source heat pumps work below 20 degrees Fahrenheit—in fact, they can perform well below -10!

How often do you need to add Freon to a heat pump? ›

How Often Does a Heat Pump Need Refrigerant? The refrigerant in your HVAC system should last as long as the unit itself, or about 15 years. However, if your unit has a leak, an HVAC professional may need to add refrigerant to your mini-split after repairs have been completed.

Will a heat pump run with low refrigerant? ›

Without sufficient refrigerant, a heat pump would lose the ability to actually operate as a heating or cooling system. Refrigerant is not consumed during normal heat pump operation, which means if your heat pump is low on refrigerant it was either not charged properly on installation or it has a leak in the system.

Why is my heat pump blowing cold air on heat? ›

When your heat pump goes into defrost mode, it switches into cooling mode, causing the outdoor coils to heat up to melt any frost or ice within the system. However, because the system is in cooling mode, it means that for a few minutes, it will blow cold air through the vents.

How do I know if my heat pump fuse is blown? ›

Test the load: If you saw a voltage reading during the previous step, run the same test on the “load” side of the fuses. You should again see a reading between 220 and 240. If you see a voltage reading on the “line” side but not the “load” side, it means you have a blown fuse.

How do you tell if a fuse is blown? ›

Remove the fuse from its holder. In some cases you may need a small screwdriver to unscrew the fuse holder cap. Look at the fuse wire. If there is a visible gap in the wire or a dark or metallic smear inside the glass then the fuse is blown and needs to be replaced.

How do I know if my HVAC fuse is blown? ›

If there is the voltage on the “line” side, test for voltage on the “load” side of the fuses by placing the meter's leads on the load wire lugs. If you read voltage on this side(220-240V), this means the current is flowing through the fuse. If you get a zero-voltage reading on the load, this means your fuse is blown.

What to check if heat is not working? ›

Heater Not Working? 7 Troubleshooting Tips:
  1. Check that your thermostat is set to “heat.” ...
  2. Change the filter. ...
  3. Make sure the gas is on. ...
  4. Clear the chimney exhaust flue. ...
  5. Clean away leaves and debris from exhaust vents. ...
  6. Flush out the drain lines. ...
  7. Check for blocked ducts restricting airflow.
16 Nov 2016

Why is my thermostat on but no heat? ›

Seeing that your home thermostat says 'heat on' while in reality there is no heat is one of the most annoying things ever. What could possibly be wrong? The most common reasons for such a problem are a dirty filter, thermostat malfunction, pilot ignitor, wrong settings, or low battery issue.

How do I reset my heater? ›

Locate the reset button on the furnace and press it to reset the furnace. It is usually located inside the blower compartment on the side of the blower motor. Be cautious as the housing may be hot. If the button is popped up, press it down.

How long does it take for a heat pump to turn on? ›

How Long Does it Take to Install a Heat Pump? - YouTube

Is the outside unit supposed to run when the heat is on? ›

The heating system is largely isolated to the interior. When you have a standard furnace, the outside AC unit shouldn't run at all. The interior system works with a few steps designed into it. As you activate the heater, a pilot light or electrical-heating element turns on.

How do I reset my thermostat manually? ›

Here are the step-by-step reset instructions:
  1. Turn your thermostat off by switching it to the off position.
  2. Find the breaker that powers your HVAC system and turn it off.
  3. Wait 30 seconds and turn the breaker back on.
  4. Turn your thermostat back on.

How do you reset a low pressure lockout? ›

A low pressure alarm indicates the controller has received an open signal from the normally closed low pressure switch circuit. Three active alarms within one hour will trigger a compressor lockout to protect the refrigerant circuit. The lockout can be cleared by power cycling the controller.

How do you reset a heat pump after a power outage? ›

Make sure the heat pump is off. You can do this during the power outage. Once power comes back on, turn the heat pump to the “Emergency Heat” setting. This will allow the compressor to warm up slowly and get the refrigerant warm enough to start flow freely again.

How do you reset a heat pump in the winter? ›

Please follow the steps below to restart your Heat Pump:
  1. 1 - Turn off the Thermostat.
  2. 2 - Turn off the Power Switch to the heat pump (located on either the.
  3. 3 - Turn off the 2 electrical breakers for the heat pump.
  4. 4 - Wait a few minutes (3 to 5 minutes should be long enough)

Why is my heat pump not blowing out warm air? ›

Heat Pump Has Leaking or Low Refrigerant

If your heat pump is not blowing warm air, the refrigerant may be the problem. The unit could be running low and need additional refrigerant added. Needless to say, this isn't something you can do on your own. A refrigerant leak can cause this problem.

How long does it take for HVAC to reset? ›

After you've turned the system back on, it will take a bit of time for the air conditioner's internal circuitry to reset. It usually takes about 30 minutes, so sit tight until then.

Is there a reset button on my HVAC unit? ›

Most air conditioning units are equipped with a reset button. These buttons tend to be red and quite small. If you're having a tough time finding it, consult your owner's manual.

Where is the reset button on the air conditioning unit? ›

Look for it first around on the exterior of your machine, especially along the bottom edge near the ground. An AC's reset button is typically red and visible, so it should be easy to spot. If you don't see a reset button on the outside, it could be located inside the unit behind the service panel.

Should I leave my heat pump on all the time? ›

While heat pumps are the most cost effective way to use electricity to heat your home during the cooler months, leaving them running day and night is not economically efficient. According to Energywise, you should switch off your heat pump when you don't need it. This is to avoid excessive energy waste.

Where is the best place to put an air source heat pump? ›

Almost always, we would recommend positioning the unit on the floor immediately outside your house or property. This has two large benefits: first, it reduces the amount of pipework you need in order for your air source heat pump to fully cater to your property, avoiding increased unnecessary heat loss.

Do heat pumps use a lot of electricity? ›

Heat pumps require some electricity to run, but it's a relatively small amount. Modern heat pump systems can transfer three or four times more thermal energy in the form of heat than they consume in electrical energy to do this work – and that the homeowner pays for.

How long do heat pumps last? ›

How Long Does a Heat Pump Last? Because heat pumps are often relied on year-round, they don't typically last quite as long as furnaces and air conditioners. Their average lifespan is about 10 to 15 years.

What is the cost of a heat pump? ›

While the national average for a heat pump runs $5,696, the final heat pump cost varies widely based on the size of the unit, the type of heat pump purchased, and its level of efficiency. Most homeowners can expect to pay somewhere between $4,133 and $7,294.

Should heat pump fan be on AUTO or on? ›

Keeping your fan on AUTO is the most energy-efficient option. The fan only runs when the system is on and not continuously. There is better dehumidification in your home during the summer months. When your fan is set to AUTO, moisture from cold cooling coils can drip and be drained outside.

Do heat pumps work below 20 degrees? ›

Do heat pumps work below 20 degrees? Yes, air source heat pumps work below 20 degrees Fahrenheit—in fact, they can perform well below -10!

Should I run my heat pump on AUTO or heat? ›

use "AUTO" mode. It's natural to think "AUTO" mode would be a more efficient setting. But if you use it, your unit runs the risk of toggling unnecessarily between heating and cooling. Your heat pump will run most efficiently when set to "HEAT" in winter and "COOL" in summer.

Do air source heat pumps need servicing? ›

Geo Green Power recommend an annual service for air source heat pumps and ground source heat pumps to ensure that they run efficiently. Heat pumps rarely require maintenance outside of this annual health check and you can expect a well-maintained system to run effectively for at least 20 – 30 years.

Are heat pumps worth it or just a lot of hot air? ›

Air source heat pumps are absolutely worth the investment, especially with the introduction of the Boiler Upgrade Scheme from April 2022.

Do heat pumps work with radiators? ›

Yes. Heat pumps can be used to heat buildings either with underfloor systems, with radiators or a mix of both. While underfloor systems are often used on lower floors, it might be that your preferred choice for heating upstairs is radiators.

Do heat pumps need to be in the shade? ›

simply put the answer is put it wherever you like. But bear this in mind, especially if your unit is old or has old software. Most units have a function where the unit wont heat above a preset temperature.

How high should a heat pump be off the ground? ›

Heat Pumps should be elevated 4 to 8 inches above ground level to keep coils clear of snow and ice and to allow for proper drainage.

Do heat pumps need to be in sun? ›

A big myth is that air source heat pumps need to be placed in a sunny position or on a south facing wall; this simply isn't true, but they should be sensibly placed in an area that isn't too confined. Also check that you have sufficient electrical power available on your fuse board for this extra appliance.


1. Diagnosing the stuck HVAC reversing valve
2. How heat pumps help decarbonize heating and cooling – an interview with Thomas Nowak
(Danfoss Climate Solutions)
3. Example Problem - Heat Pump
4. TOP 5 CONTACTOR Troubleshooting Problems!
(AC Service Tech LLC)
5. This is Why Heat Pumps May NOT Be The Future
(Skill Builder)
6. Top 10 Heating Problems EASY Fixes for No HEAT - Boiler / Furnace Troubleshooting OIL HEAT
(Silver Cymbal)

Top Articles

Latest Posts

Article information

Author: Ouida Strosin DO

Last Updated: 12/30/2022

Views: 6004

Rating: 4.6 / 5 (76 voted)

Reviews: 91% of readers found this page helpful

Author information

Name: Ouida Strosin DO

Birthday: 1995-04-27

Address: Suite 927 930 Kilback Radial, Candidaville, TN 87795

Phone: +8561498978366

Job: Legacy Manufacturing Specialist

Hobby: Singing, Mountain biking, Water sports, Water sports, Taxidermy, Polo, Pet

Introduction: My name is Ouida Strosin DO, I am a precious, combative, spotless, modern, spotless, beautiful, precious person who loves writing and wants to share my knowledge and understanding with you.