Heat Pump Not Heating Troubleshooting

Heat Pump Not Heating Troubleshooting Guide

Troubleshooting a heat pump might seem a little complicated, but it is not impossible. When your heat pump fails to meet heat or cooling demands, there could be more than one reason. Sometimes, the solution might be as minor as turning a simple, and sometimes it’s bigger than that.

This article will help you understand everything you need to know about heat pump not heating troubleshooting. Before diving straight into troubleshooting, it’s important to understand what a heat pump is and how it works.

What is a Heat Pump

The pump is a part of a heating and cooling system. During the colder season, it is used to provide heat to the home and cooling in the hotter season.

One of the most attractive aspects of the heat pump is how energy efficient they are. It has up to 360degree energy efficiency, which means it provides more heat energy than the electrical energy it consumes. Furthermore, the energy efficiency of a heat pump allows you to use less energy and save on energy bills.

How Does A Heat Pump Work

Heat Pump

It’s simple. The heat pump transfers heat from one place to another instead of burning fuel to make heat.

When in heating mode, a heat pump absorbs heat energy from the outside air, then transfers it to the inside air. In cooling mode, a heat pump absorbs heat from the indoor unit and releases it through the outdoor unit, just like an air conditioner.

There are two main types of heat pumps:

  • Air source heat pump 
  • Ground source heat pump

Air Source Heat Pump

The air source heat pumps conduct heat transfer between the air outside your home and your home. They use the outside air as a heat source when in heating mode or the heat sink when in cooling mode.

Air source heat pumps use a vapor-compression refrigeration process, heat exchanger, and a fan to produce heat and cooling, just like an air conditioner.

They are two types of air-source heat pumps.

Ducted Heat Pump

The ducted heat pumps have one central unit connecting the indoor and outdoor units. This unit heats or cools your home through the home ducts. 

Ductless Heat Pump

The ductless heat pumps are not as invasive as the ducted heat pumps. It only needs a tiny hole in the wall to connect the indoor and outdoor units. 

Ground Source Heat Pump

The ground source heat pump conducts the transfer of heat between the air inside your home and the ground outside. It comprises a network of water pipes buried underground and a heat pump at ground level.

The ground source heat pump absorbs the natural heat in the ground and then transfers it into your home through the pipes.

A combination of water and anti-freeze is pumped into the pipes to absorb the heat. The water mixture is then turned into usable heat by the heat exchanger.

The heat exchanger extracts the heat from the water mixture and then transfers the heat to the heat pump. The heat pump then pumps the heat into your home’s heating system

Top Ten Heat Pump Problems And How to Troubleshoot Them

Identifying the main problem of your heat pump can be a little complicated since it could be a lot of things. However, it is not impossible to diagnose and fix with a proper investigation and a few simple instructions.  

Here are the top ten most common heat pump problems and their troubleshooting tips: 

Heat Pump Not Running

Heat Pump

If your heat pump is not turning on, there are a few easy troubleshooting steps you can follow to fix it. But, sometimes, you might need to consult with a trained professional to conduct a proper diagnose.

However, below are the likely causes for your heat pump not turning on.

Faulty Thermostat

The thermostat regulates the temperature of your heat pump. It tells it when to turn on and off as well as what temperature to maintain. If your heat pump’s thermostat stops working, it cannot tell the heat pump to do anything like turn on.

So, if your heat pump is not working, the first to check is the thermostat.

  • First, check the thermostat’s display. If the display does not have power, then it means that the thermostat has not to matter. To fix this, replace the thermostat’s batteries. 
  • For hardwired units, check your home’s electrical board. In most, cases the circuit breaker may have tripped, or a fuse may have blown. If the circuit breaker is tripped, turn it back on. And if you see a blown fuse, then replace it. 

Note: Before replacing the fuse, first turn off the electrical power.

Power Loss

If the thermostat has power, check the power supply to other system components of your heat pump. The indoor and outdoor units of your heat pump are operated with different control switches.

  • First, check the power switch located on or near the indoor unit to see if it is on. If the power switch is off, then turn it back on.  
  • Next, check the other power switch located on or near the outdoor unit and set it to oN if it is not. 
  • If none of the above instructions worked, then check your home’s electrical panel. Make sure the circuit controlling the indoor and outdoor units is not disrupted by a tripped breaker or a blown fuse.
  • If the circuit breaker is tripped, reset it. And if the fuse is blown, then replace it. 

Blocked Registers

If your heat pump is ducted, check to see if the registers are open. If the registers are obstructed by objects in the house like furniture or toys or clogged with dirt, it may feel as though the heat pump is not working.

  • If an object blocks the register, remove it to restore the flow of heat or cooled air onto your home. 
  • If there is still no flow, then the registers are likely clogged. Consult a trained professional to unclog the registers

Clogged or Dirty Air Filters

Your heat pump will stop receiving fresh air if its air filter gets dirty or clogged. And when the air filters are clogged or dirty, the heat pump has to work overtime to maintain your desired temperature. Also, when the heat pump overworks, the stress can cause it to overheat and possibly shut down completely. 

  • Take out the air filters for inspection. Hold them out against a light source and check for an obstruction. If you can look through them without any obstructions, then your air filters are clean. 
  • If the air filter is not clean, then wash them with soapy water and let them dry. 

Faulty Starter Capacitor

The starter capacitor supplies power to the motor driving the heat pump. It provides enough energy to turn on the unit.


So, if anything happens to the starter capacitor goes bad, your heat pump will not turn on. If you notice any noise like a clicking sound when you turn on your heat pump, then that is that your starter capacitor is faulty.

  • If you can replace the starter capacitor on your own. Be careful when handling it because it carries a very high amount of electric charge. It can electrocute you even with the power disconnected. 
  • However, if you cannot replace the stater capacitor yourself, please consult a trained professional.

Faulty Reversing Valve

The reversing valve is one of the major components in the heat pump that allows it to produce heat or cooled air. As the heat pump changes mode, the reversing valve opens and closes.

  • If your heat pump only turns on for one of the modes, it means something is wrong with the valve. Contact a trained professional for proper inspection. 

Frozen Outdoor Unit

Heat Pump

Sometimes during the colder seasons, the outdoor unit of your heat pump can be covered by the light layers of ice. When this happens, it can prevent the heat transfer between the outside coil and the air.

In typical cases, the heat pump will go into defrost mode to remove the ice layer. But, if the ice is left on the external unit for a long time, it can prevent the heat pump from providing proper heat to your home and possibly permanently damage it. 

Below are the possible causes of a frozen outdoor unit and some troubleshooting tips:

Blocked Outdoor Unit

An existing accumulation of snow around the outside unit can stop any ice sticking to the outdoor unit from melting. 

  • Clean out snow from the area around the outside unit. 
  • Use water to melt away the ice. Remember not to use any sharp object to take out the ice as it can cause damage to the coils. 

Faulty Outdoor Fan

The fan is important to the heat transfer process needed to heat and cool your home. It blows air over the coil with refrigerant in it. If your outdoor fan is faulty, there will be no airflow, causing the outdoor unit to freeze over.

  • If this is the case, then contact a trained professional to inspect the outdoor fan and motor. 

Low Refrigerant

A refrigerant leak often causes this. There will not be a proper heat transfer if there is a refrigerant leakage in your heat pump. This means your heat pump will not be able to produce enough heat to melt the ice on the outside unit. 

  • If you suspect a refrigerant leakage, please do not attempt to fix it on your own. 
  • Contact a trained professional immediately. 

Unit Not Defrosting

Occasionally, the heat pump switches to air conditioning mode to defrost the ice on the outside unit in the winter. The air conditioning mode heats the unit in order to melt any ice or frosts. The ice, however, can build up quickly if the unit is not defrosting. 

  • If the reversing valve of your heat pump spoils, the unit will not defrost. The reversing valve is responsible for switching the heat pump from heat mode to air conditioning mode. 
  • Contact a trained professional to inspect the reversing gas valve. 

Clogged Filters

Airflow can be blocked by clogged or dirty air filters. If enough air does not circulate the coils, the coil will get too cold and then eventually freeze over. Frozen coils cannot heat or cool properly, thereby causing more ice to accumulate on the outside unit. 

  • Contact a trained professional for help. 

Dirty Coils

Dirty coils can affect heat transfer effectiveness between the coils and the outside air. If the coils fail to lose heat to the air, the refrigerant inside them will become too cold.


This can cause a layer of ice to form on the coils, resulting in the heat pump not heating or cooling properly. The heat pump, not heating properly also makes the icing on the outdoor unit worse. 

Water on Outdoor Unit

In winter, if in any way water happens to drip continuously on the outdoor unit, it can freeze and form a layer of ice. 

  • Turn on the defrost mode or spray water to defrost the outside unit. 
  • Now locate the source of the water and fix it.

Faulty Indoor Air Handler 

Heat Pump Replacement

The air handler in the heat pump is essential for the distribution of air inside your home. If you don’t feel any air coming from the registers while the outdoor unit is on, then your indoor air handler may not be running.

Here are some possible causes for your indoor air handler not running and how to troubleshoot it: 

Tripped Circuit Breaker or Blown Fuse

As mentioned above, your heat pump’s indoor and outdoor units have separate electrical connections. 

  • Check the circuit breaker of your indoor unit. If you detect a tripped breaker, reset it. If the circuit breaker keeps tripping, then contact a trained professional. 
  • And if a fuse is blown, then a replacement is required. 

Wrong Connection of the Wire

Another possible reason for the air handler not running is a loose or frayed wire. This can prevent power from reaching the indoor air handler. 

  • If you suspect or notice a bad wiring connection, contact a trained professional. 

Faulty Blower Motor

Finally, if none of the above instructions have worked so far, the last option is the blower motor. The blower motor of the heat pump circulates air throughout your home. If the blower motor is blown, it means that the heat pump cannot distribute air across your home. 

  • In this case, contact a trained professional to replace the blower motor. Please do not attempt to replace it on your own.

Heat Pump Not Heating

Heat Pump Troubleshooting

It can be uncomfortable when your heat pump stops producing heat, especially during the winter.

Below are the most likely reasons why your heat pump would stop producing heat:

Wrong Thermostat Settings

An incorrect thermostat setting can result in your heat pump not producing heat. 

  • For heating, check the thermostat to see what mode it’s in. If the thermostat is in cooling mode, set it back to heating. 
  • For cooling, follow the same process as mentioned above and make sure it’s set to cool. 
  • If none of the above worked, check your fan to see if it is constantly running. If the fan is continuously running, it means the system is not running actively. In that case, set the system to heating mode and the fan to auto. 

Wrong Thermostat Calibration

A proper thermostat calibration makes sure that the sensor correctly reads your home’s temperature. If something is wrong with the calibration, your thermostat could be reading the wrong temperature, which can cause heating problems. 

  • First, check the thermostat’s manual to see if there are any instructions you can follow on your own. 
  • If not, please get in touch with a trained professional to either replace or calibrate the thermostat professionally. 

Clogged or Dirty Air Filters

If the air filters of your heat pump have not been cleaned or replaced in a while, dirt or debris can clog them, therefore, leading to reduced or no airflow. No air flow means no heating. 

  • Wash the air filters with soapy water to clean and unclog, or replace them if necessary. 

Low Refrigerant

A low refrigerant affects the heat transfer of the heat pump, therefore not producing warmth to your home. Leaks often cause low refrigerants. 

  • Sadly, you cannot fix refrigerants on your own. Contact a trained professional to fix this.

Blocked Outside Unit

A blocked outdoor unit cannot pull air from outside, which means your heat pump cannot transfer heat.   

  • Clean the snow or any debris from the outdoor unit to fix this. 

Ducts Leakage

A leaking ductwork can result in your heat pump not providing enough heat to your home. 

  • Contact a trained professional to fix this. Do not attempt on your own. 

Heat Pump Not Cooling

Heat Pump

Below are some possible reasons why your heat pump stopped producing cooled air.

Faulty Thermostat

As mentioned above, a defective thermostat can affect the performance of the heat pump. 

  • To fix this, first check to make sure your thermostat is set to cool mode. 
  • If the settings are correct, then contact a trained professional to calibrate the thermostat correctly. 

Faulty Reversing Valve

You will likely have a faulty reversing valve if your heat pump works in heating mode but not in cooling mode. 

  • If this is the case, contact a trained professional to replace the valve. Do not attempt on your own. 

Low Refrigerant

Your heat pump will not cool or heat appropriately if its refrigerant level is low. Also, low refrigerant means there may be leakage. 

  • please get in touch with a trained professional to check for leaks before refilling the refrigerant. 

Dirty or Clogged Air Filters

If your air filters are dirty or clogged, they cannot be able to draw enough air from the inside to cool appropriately. 

  • A regular cleaning or replacement is advised to fix this. 

Blocked Outdoor Unit

If the outdoor unit is blocked by anything, it will not pump out hot air, which means the heat pump cannot cool properly. 

  • Clean the outdoor unit area to clear the blockage. 

Dirty Coils

If the coils of your heat pump are dirty, there will not be heat transfer between the refrigerant in the coils and the air. 

  • Clean out any dirt or frost from the coils if any is found. 
  • Remember not to remove ice physically to avoid causing damage to the coils. Allow any ice to melt on its own. 

Undersized Unit

Another possibility of your heat pump not being able to cool properly is that it may be too small for your home. 

  • Contact a trained professional to determine if your heat pump is the right size for your home.   

Heat Pump Not Staying On

Below are a few possible reasons why your heat pump keeps turning off on by itself whenever you turn it on.

System Overheat

System overheat is often caused by restricted airflow, and as you know by now, restricted airflow means that the air filters of your heat pump are either clogged or dirty. 

  • Clean the air filters with soapy water to unclog. 
  • If the heat is still overheating, then contact a trained professional.  

Oversized Unit

If you have a bigger heat pump than your home, it will cool or heat your home too fast, and once it gets to the highest, it will shut down. 

  • Contact a trained professional to determine if the heat pump is the appropriate size for your home. 

Wrong Thermostat Calibration

An incorrect thermostat calibration means that your heat pump’s thermostat will not be able to read correctly; this can result in your heat pump turning on and off. 

  • Check to make sure the thermostat is calibrated correctly. 
  • If you can calibrate or replace the thermostat on your own. And if you can’t, contact a trained professional. 

Refrigerant Leaks

Your heat pump may not have enough refrigerant for an entire cycle if the refrigerant is leaking. 

  • Only a trained professional can fix this, do not attempt on your own. 

Liquid Leakage

It is dangerous to avoid liquid leakage from the heat pump. A fluid leak from the heat pump causes not only decays and stagnant water but also electrical damage. 

Here are some reasons your heat pump would be leaking liquids and how to troubleshoot it.

Refrigerant Leak

Ice can form on the evaporator coils if you have a refrigerant leak, reducing the effectiveness of your heat pump. Furthermore, when your heat pump is turned off, the ice melts, causing your heat pump to leak water.

  • Contact a trained professional to fix leaks. 

Clogged Drain Line

The heap pump draws air into your home to cool when it’s on cooling mode, leading to evaporation. Condensation is the outcome of this process. The vapor is drained through the drain line after passing through the condensate pan.


If there are any cracks on the condensate pan, water can leak through there. A clogged drain line, on the other hand, can cause water to overflow.

  • If this is the case, contact a trained professional to fix it. 

Strange Odor

When your heat pump stops functioning appropriately, a weird smell can mean something serious and should be checked out. 


Here are a few reasons why your heat pump may be giving off a strange odor and how to troubleshoot:

Mold Growing In Heat Pump

If you happen to smell any musty odor, this could mean that a mold is growing inside your heat pump or around the walls. If a mold is present in the ducts of your heat pump, it could potentially cause harm to your health. 

  • Turn off the heat pump to avoid the circulation of mold spores in your home. 
  • Then clean out the mold from the unit if it’s not too much. 
  • However, if the mold has grown too much and there’s a significant mold in the unit, contact a trained professional to deep clean. Sometimes if the damage is too severe, the whole unit might need to be replaced. 

Infiltration by Small Animals

Sometimes, small animals can crawl into the heat pump and die due to overheating, cold, or suffocation. If you smell any rotting odors from your heat pump, then chances are there is a dead animal inside. 

  • Open the heat pump by first removing the cover. 
  • Then take out the carcass if you can. 
  • If you are having difficulties taking all of it out, contact a trained professional for help. 

Electrical Problems

If you smell the burning odor from your heat pump, it means there’s electrical damage inside. 

  • Once you detect an electrical issue from the heat pump, turn of the circuit breaker and contact a trained professional immediately. 

Continuous Running of the Heat Pump

Heat Pump

Typically, the heat pump is designed to run constantly in order to provide the desired temperature. But sometimes, there may be other reasons why the heat pump is continuously running. Here are some reasons why your heat pump is running too much and how to troubleshoot it.

Faulty Compressor Contactor

The compressor contactor controls the flow of electricity to the components in your heat pump. If the compressor contactor breaks, it could cause your heat pump to run constantly. 

  • In this case, contact a trained professional for a proper diagnose. 

Refrigerant Leak

Heat cannot transfer appropriately in the heat pump if the refrigerant charge is low. Without a proper heat transfer, the heat pump will not be able to produce enough heat and cooled air which means the heat pump has to run constantly to maintain the desired temperature. 

  • In this case, don’t hesitate to contact a trained professional to conduct a proper diagnosis. Do not attempt on your own. 

Dirty or Clogged Filters

Another possibility for your heat pump running constantly is dirty or clogged filters. If you have not cleaned or replaced the air filter in a while, this is the cause. 

  • Check the air filter and clean any dirt if you find any. 
  • If it’s clogged, then contact a trained professional. 

Wrong Thermostat Settings

Your heat pump works continually to maintain the specified temperature if the thermostat is set too high or too low.

  • Check to make sure the thermostat is set accurately according to the weather and your desired temperature. 
  • In the summer, the heat pump should be set to 78ºF. From 78ºF, you can then adjust to your desired temperature. 
  • In the winter, the average temperature for the heat pump is 68ºF to 72ºF. 

Undersized Heat Pump

An incorrectly sized heat pump can be a reason for it running constantly. If your house is too big, your heat pump will have to run constantly to achieve the right temperature. 

  • If you think the heat pump is too big for your house, contact a trained professional to determine the compatibility. 

Heat Pump Not Switching Modes

If your heat pump is having issues with switching from heating to cooling or vice versa, it means the reversing valve is faulty. The valve is responsible for changing the heat pump from one mode to another. 

  • If you suspect your heat pump valve is faulty, contact a trained professional to replace it. 

Frequently Asked Questions (FAQs)

Question: How Often Should a Heat Pump be Maintained?

Answer: The heat pump should be maintained regularly, especially cleaning. You should clean your heat pump once in a while to avoided dirt accumulations.

Question: How Much Does a Heat Pump Cost?

Answer: The cost of heat pumps ranges from 1,500USD to 30,000USD, depending on the type of heat pump you want.

Question: How Much Does it Cost to Maintain the Heat Pump?

Answer: Professional maintenance of the heat pump costs around $156 to $174.

Question: Can the Heat Pump Produce Enough Heat for House?

Answer: The heat pump can produce enough heat for an entire house.

Question: Do Heat Pumps Work in Colder Weather?

Answer: Yes, it can. The heat pump is highly efficient.


We all value the comfort of a well-heated or cooled home. Like any other heating system, the heat pump does a great job at providing the desired temperature while lowering the cost of energy bills.

A faulty heat pump means there will be a shortage of that comfort and potential harm to our health. This article contains all instructions on how to troubleshoot a heat pump.


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