Top 5 Heat Pump Problems: Troubleshooting the Popular Brands

Carolina Evans
Carolina Evans
Research Writer
Holds a Master’s degree in Engineering and is keen on her own home’s climate. Sometimes we think that Carolina owns every single product she writes about – that’s ho read more
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Richard Powell
Richard Powell
Expert Consultant
For 8 years, Richard had been working as an HVAC specialist and AC unit installer since his student years. Now, he’s our main consultant on every technical aspect that may read more
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A heat pump puts out 2 or 4 times Trusted Source Heat Pumps - Performance and Efficiency Ratings - The Engineering ToolBox Several methods can be used to rate heat pump performance and efficiency. as much energy as it consumes. Compare that to 95% energy conversion for a furnace or 100% energy for infrared heaters. This makes heat pumps the most efficient home heating option.

However, even the best heat pumps are vulnerable to various challenges. When your heat pump starts acting up, look out for these common heat pump problems that you can easily troubleshoot and solve at home.

Top 5 Heat Pump Problems: Troubleshooting the Popular Brands

Top Heat Pump Problems

Heat pumps are like just reverse refrigerators, which means that there is a host of problems from which they can suffer. When your heat pump starts acting up, you will definitely feel the difference in your home temperature.

Before you call in the professional heat pump technicians and possibly lose money and time on what could be just a simple fix, try going through these troubleshooting procedures.

The Heat Pump Won’t Turn On

When your heat pump won’t come on or the outdoor unit won’t show any signs of being operational, there are several reasons why this could be.

Loss of power

This is one of the most common reasons why your heat pump won’t turn on. Check whether the circuit breaker has tripped and if so, turn it back on. You should also check whether you have a blown fuse in the panel box. If these two are okay, confirm that the unit’s emergency switch is on and that the outdoor reset button hasn’t tripped.

Faulty thermostat

Your pump’s thermostat is meant to tell the unit when to turn on and off. However, if the thermostat fails or goes into emergency mode, you may need a replacement. If your unit has a manual override switch, try cranking it and see if it runs. In any case, your unit will require a professional visit.

Bad starter capacitor

Like any modern electric motor, the air compressor unit of your heat pump requires a capacitor to supply the required starting force. If this capacitor is bad, you may experience any of the following symptoms.

  • A burning smell or smoke coming from your outdoor unit
  • The fan hums but no air seems to blow into the house
  • The unit stutters as it attempts to turn on

Bad capacitors require professional assistance to diagnose and replace if necessary.

Faulty control module

Your unit’s control module may also be faulty due to a problem with the wiring or simply from physical damage. The unit will not turn despite having power until the module is replaced.

The Heat Pump Is Not Heating

The most common reason why your heat pump may not be heating is because of thermostat problems. You should first check that the thermostat is properly programmed with time and temperature.

To check on thermostat issues, see if the temperature it displays is the same as that shown on an independent device. Also confirm that mode shown on the thermostat is indeed the mode that the unit is in, that is, On/Off, Auto, Heating, or Cooling mode.

The third reason why your unit would not be working is a problem with the reversing valve. This valve is responsible for converting the heat pump mode from heating to cooling. It does so by reversing the flow of refrigerant from one direction to the other.

If the pump is cooling but not heating or vice versa, this could be a problem with the reversing valve. In that case, have a technician take a look at your heat pump.

Other reasons why your unit may not be heating your house include:

  • The unit’s refrigerant is low or leaking. This is usually accompanied by frozen coils
  • If the outside temperature is too chilly (below 30F), there won’t be enough ambient heat for the heat pump to absorb. Some heat pumps are equipped with an auxiliary unit, although some people opt to install a furnace to support the heat pump unit. Find more detailed information about heat pumps and furnaces in this guide
  • If the outdoor unit is clogged or frozen with ice, it won’t be able to exchange heat with the circulating air. Leave this to the professionals because you can easily rupture or burst the delicate copper tubes if you attempt to unclog the unit yourself
  • A dirty or clogged air filter can prevent proper airflow and thus reduce your unit’s efficiency to zero

The Heat Pump Is Not Cooling

In reverse mode, a heat pump becomes a very efficient cooling system. However, if you perceive that the air coming out of the vents is either warm or there is very little air, check the following:

  • Check the thermostat. Make sure that it is properly calibrated and displaying the right mode and ambient temperature. Sometimes replacing the thermostat battery is all you need to d
  • If there is very little airflow, check the air filter and clean or replace it
  • If the air seems warm or not very cold to you, it’s possible that your refrigerant is low or is leaking. Have a technician check that out for you
  • A problem with the reversing valve can also have the unit stuck on heating mode instead of cooling

If you need a unit that does a lot more than moderate heating and cooling, an integrated mini-split heat pump and air conditioner is probably your best solution. Such a unit can serve as a replacement to conventional central heating and cooling systems while taking up less space and being much quieter.

One of the most recommended ductless mini-splits is the Pioneer Air Conditioner. As a top-quality model, many users appreciate the effective heating and cooling offered by this unit which leaves no hot or cold spots. As a bonus, this unit stays whisper-quiet.

The Heat Pump Is Running Constantly

At low outside temperatures, your heat pump will probably be running full-out to keep your inside temperatures comfortable. However, that shouldn’t happen at temperatures above 40F and certainly not in mild weather.

If the unit is running constantly instead of cycling on/off when required, that could be a problem with any of the following:

  • Low heat pump efficiency, which can be caused by lack of proper home winterization or low refrigerant levels
  • Improper airflow caused by a clogged air filter, interference near the outdoor unit
  • Thermostat problems. Ensure that the thermostat is set to the correct temperature and mode
  • Broken control unit. With broken controls, the heat pump won’t be able to turn itself on and off properly
  • The outdoor unit may be clogged or frozen. In this case, the heat exchanging coils won’t be able to work properly and will force the unit to run constantly
  • Broken refrigerant pump. If the condensate is not getting pumped, the whole unit might keep running constantly to compensate

The Heat Pump Is Making Strange Noises

A heat pump is not exactly a quiet device, especially when it is working really hard deep in the winter. You will have many defrost cycles, increased compressor sound, shifting valves, pressure equalization, and more. So, what noises qualify as “strange” in this case?

  • Metal-on-metal grating sounds – these should definitely not be there and could signify something wrong with the fans. They could have ice buildup causing them to scrape, or a piece of foreign matter. Faulty bearings could also cause this problem
  • Constant gurgling – this is a noise that usually indicates low levels of refrigerant, an issue which you should have professionally addressed right away
  • Shaking and vibrating – this problem can come from the outdoor unit when rotating parts come off-balance or become obstructed. A busted air compressor can also cause severe shaking, especially when starting. However, a gentle vibration when starting and running is to be expected
  • Whistling sounds indicate air loss somewhere in the ducts
  • Rattling and buzzing could be a sign of valve problems or loose parts. If you hear loud rattles especially in the outdoor unit, it’s wise to have a professional look at it

York Heat Pump Problems

Top 5 Heat Pump Problems: Troubleshooting the Popular Brands

York is one of the biggest heat pump brands. They are very popular because of their reliability, ease of maintenance, and long warranty. That being said, there are still some common problems that affect York heat pumps that you can easily troubleshoot.

1.   Thermostat problems

As described above, a problem with your thermostat could cause any number of problems including inadequate heating, cooling, or constant running of the unit.

If you suspect that your York heat pump has such a problem, the built-in override switch is the easiest way to rule that out. Remove the snap-on cover on the thermostat to access the override switch beneath and see if the pump runs.

2.   Problems with the outside unit

There are many reasons why you may want to check with the outside unit such as clogged or frozen coils. To access the inner parts, use a screwdriver to remove the screws holding the outer cover in place. If the heat pump coils are dirty, you can use a whisk broom to clean them gently. Check also that the fan is spinning.

3.   Cleaning the air filters

The air filters are contained in the indoor unit. Simply open up the outer cover and remove the air filters. You can clean them by washing them with warm water and soap or simply using a vacuum cleaner to suck up any dust and debris.

4.   Making sure the unit is ON

York outdoor units have a separate disconnect switch, which is a small grey metal box usually mounted near the unit onto the wall. Confirm that it on and that the blow motor is working. If nothing is still happening, continue with the troubleshooting checklist above such as checking the circuit breakers.

American Standard Heat Pump Problems

Top 5 Heat Pump Problems: Troubleshooting the Popular Brands

American Standard is another very popular heat pump brand. Like any other, however, you are likely to experience a few problems, most of which you can hopefully clear up yourself without too much trouble. Here are some of the known issues.

1.   The unit keeps tripping breakers

This is definitely an electrical problem, so you need to contact a professional to deal with it.

2.   Thermostat problems

Just like most other units, thermostat problems can arise from issues such as wrong programming or lack of communication. These can be resolved by resetting and/or replacing the batteries.

To rest your AS heat pump thermostat, simply take it from the wall and remove the batteries. You can discharge it by leaving it for a few hours without the batteries or simply reverse the battery polarity for a few seconds then start it again. You can also replace the batteries this way to see how it goes.

Other thermostat problems include:

  • No display – a blown fuse or lack of power is likely
  • The display goes on and off – there is no 360-ohm resistor. Installing one should solve the problem
  • The temperature limit is stuck – you may have reached the maximum allowed values
  • Under/overshooting the temperature value indicate extra-fast cooling and heating
  • No response from the keypad processes – the keyboard may have failed

The different thermostats also have their own individual codes which you can use to refer back to the owner’s manual to find the exact cause. For example, error code 79 represents low pressure or a failed seer switch.

3.   Low airflow

Check with the air filter first and confirm that the filters are clean and not clogged up. The air filters are easily accessible from your indoor unit. The second most common problem is an issue with the compressor. If the unit turns on but has poor airflow, check with the status LEDs and match it with the codes.

  • 7 red flashes indicate a low-pressure problem
  • 17 red flashes indicate a high-pressure problem

4.   Unit not heating or cooling

If you have already confirmed that the unit’s filter and outside unit do not have obstructed airflow, check the thermostat and refrigerant.

  • Amber light – refrigerant is required
  • 5 red flashes – you have a problem with the ambient temperature sensor
  • 6 red flashes – there is a fault with the coil temperature sensor. Also check that the coil is not clogged or frozen
  • 13 red flashes – you have a problem with the outside temperature sensor

Lennox Heat Pump Problems

Lennox is another big brand name when it comes to heat pumps. It has been in the business for a long time and made a name, although there have been a lot of dissatisfied customers in the past.

As long as we’re keeping it honest, Lennox has had a bit of a chequered history with the quality of its heat pumps. The main issue has been its evaporator coils, some of which seem to give up within 5 years of purchase instead of the proposed 10-12. In case you might want to consider replacing your Lennox unit, consider getting one of the best Goodman or Daikin heat pumps.

Lennox heat pumps will display an error code or a list of them in place of the temperature if there is a problem. It’s always advisable to take note of these before you contact technical support or call in a professional, and they will have the lookup information for diagnostics.

1.   Inefficient heating or cooling

Check for obstructions to the system, including air filters. If there are none, check the fan speed. You should also make sure that your home is properly winterized.

2.   Frozen indoor evaporator coil, no airflow

This is the most common sign of refrigerant leak. Shut the unit down and contact technical support immediately.

3.   Unresponsive thermostat

Lennox uses a wireless system to communicate between your remote control and thermostat. If the latter is unresponsive, use the manual power button to turn the unit OFF then ON and give it a few minutes to start. If you still have a problem, contact a technician.

If you are using the iComfort smart thermostat:

  • Check that the unit’s AAA batteries are good and replace if necessary
  • Flashing or steady amber light – this shows a WIFI connection problem. Ensure that the unit is connected to a WIFI network.
  • Flashing red indicator – this shows a problem with one or more of the unit’s functionality
  • Alert code showing on the unit – compare the code against your user manual and act accordingly

PS: If you are going to rely on your heat pump for the winter, make sure that you have an efficient water heater to go with it. A tankless water heater such as the Rheem Direct Vent system provides on-demand hot water with minimal delay. Except for the installation which can be a headache, this is the one system with excellent user reviews after years in the market.

Final Thoughts

A top-quality heat pump is your best bet for efficient and affordable home heating or cooling. With proper maintenance and care, your unit ideally should not be giving you any problems, but sometimes things happen.

These common heat pump problems can happen with any heat pump brand. The solution is to know your system inside out and learn your user manual so that you tell when a problem arises.

Here’s another handy tip for you: over 70% of heat pump problems are caused by installation errors. Always make sure that you have professional technicians install and service your units to minimize these problems in the future.


Heat Pumps - Performance and Efficiency Ratings - The Engineering ToolBox
Several methods can be used to rate heat pump performance and efficiency.
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