How To Unstick A Heat Pump Reversing Valve: A Complete Guide

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By Debarghya Roy


Are you having trouble with your heat pump’s reversing valve? A stuck reversing valve can lead to many issues, so it’s important to know how to unstick one yourself. Here we provide the information you need on understanding and troubleshooting a stuck reversing valve, i.e., from inspecting and cleaning it to replacing components, as well as tips on maintaining this critical component for peak performance.

How To Unstick A Heat Pump Reversing Valve

Image of a reversing valve of a heat pump

Key Takeaways

  • Understand the definition and function of a heat pump reversing valve, familiarize yourself with common issues that occur, and be aware of potential symptoms like low system pressure, reduced airflow from indoor vents or warm air being blown instead of cool.
  • Inspect capillary tubes for any buildup and clean regularly to avoid blocking, check for correct voltage in power supply and replace/repair faulty components if needed.
  • Frost buildup on outdoor coil caused by extreme weather conditions can cause serious problems, so it is needed to have your heat pump serviced before such events to make sure all parts are functioning properly.
  • Be mindful when handling electrical parts as this could result in electrocution, fire damage or even voiding certain manufacturer warranties; take proper safety precautions such as turning off the power before attempting repairs yourself.

Definition And Function Of The Reversing Valve

The reversing valve is a component in the refrigerant flow system of a heat pump. This device consists of two parts, a coil and a valve body, which helps it switch the direction of liquid refrigerants faster than usual methods within these systems.

When switched one way, it redirects the cold gas towards the indoor evaporator coil for heating capacity and when reversed, directs warm air out through condensing units to cooling areas.

It works in tandem with other components such as check-valves inside your heat pump to help regulate the amount of pressure inside your home or building’s HVAC unit for enhanced efficiency.

As its name suggests, reversing valves can reverse elements like hot-gas bypasses that will cause temperature swings unless secured correctly by this particular valve assembly.

Common Issues That Occur With The Valve

One of the common issues that occurs with a reversing valve on a heat pump is when it gets stuck or malfunctions. This can prevent the flow of air from switching between heating and cooling mode, which drastically reduces its effectiveness in both modes.

There are several signs to look out for if you suspect your reversing valve is malfunctioning.

Malfunctioning reversing valves can be caused by mechanical or electrical issues such as worn components, dirty coils, blocked filters, damaged wiring connections, low refrigerant levels or frost buildup due to extreme weather conditions.

It’s important to inspect all parts carefully for any build-up of debris and test points where possible so you know exactly what needs replacing before tackling any repairs yourself, otherwise hiring an HVAC professional might be necessary for harder fixes like replacing solenoids or compressor valves.

Symptoms Of A Stuck Reversing Valve

A stuck reversing valve can cause your heat pump to malfunction, resulting in no heating or cooling. It is important to know the signs and symptoms of a stuck reversing valve so that it can be diagnosed and fixed before more serious damage occurs.

Issues such as low system pressure, reduced airflow from indoor vents, warm air instead of cool or vice versa, and loud noises are common signs that something is wrong with your unit’s reversing valves.

If you notice any of these problems, then it’s time for an inspection by a professional technician.

In addition to the mentioned issues, there may also be visible signs which indicate repair is needed on the reversing valve itself. 

These include debris around the solenoid coil area; corrosion along electrical contacts; foreign materials lodged inside the cover; bent terminals connected directly to the body of a stuck open reverser valve; damaged units due to frost build-up during extremely cold weather conditions etc. It’s important to check all these areas when trying to figure out why your heat pump isn’t working correctly.

Causes Of A Stuck Reversing Valve

The three most common causes of a stuck reversing valve are 

  • dirt and clogs, 
  • electrical or mechanical issues, 
  • frost buildup caused by extreme weather conditions.

Dirty Or Clogged Valve

A cleaning or clogged reversing valve on a heat pump is an incredibly common issue that can cause the entire system to fail. Clogging of the valve occurs when dust, dirt, and debris build up in the capillaries.

This debris impedes the flow of liquid refrigerant, reducing airflow into individual rooms and causing performance drops throughout your home’s heating system. If ignored for too long, this buildup can lead to severe problems like a stuck reversing valve due to blockages within the lines.

Fortunately for heat pump owners, there are steps you can take to avoid these costly issues and keep your reversing valves in good working order. Regularly inspecting and cleaning the capillary tube should be part of a comprehensive maintenance plan as it helps prevent blockages from occurring.

Additionally, if temperatures drop below-zero during winter weather conditions be sure to clean off any frost buildup on or around your unit’s coils before turning them back on as this too might increase chances of getting stuck reversing valves.

Electrical Or Mechanical Issues

Electrical and mechanical problems are a common cause of reversing valve malfunctions in heat pumps. Electrical issues, such as incorrect voltage or power surges, can prevent the solenoid within the reversing valve from operating properly, causing it to stay stuck in one position.

Similarly, mechanical failures can cause the valve to remain stuck in either heating or cooling mode until replaced or repaired. If these issues aren’t resolved quickly, there may be serious ramifications for your HVAC system’s overall performance and efficiency.

For instance, an improperly-working reversing value that is stuck in cooling mode could lead to refrigerant overcharging or compressor burnout due to excessive temperatures produced by the system when trying to generate excess cool air.

Frost Buildup Due To Extreme Weather Conditions

Frost buildup on a heat pump’s outdoor coil can cause it to malfunction, particularly when it comes to the reversing valve. 

The reversing valve reverses the flow of refrigerant between heating and cooling mode and when it becomes stuck in one mode or another, the unit will only work for one type of action.

Frost buildup on the outside coil can be a contributing factor to this as well. Frost buildup puts additional strain on an already overworked system, decreasing efficiency and leading to issues with both airflow and pressure levels within the system. That can then reduce proper operation of components such as expansion valves and check valves and eventually lead to malfunctions in other parts as well, including sticking of the reversing valve due frosty accumulation around its parts.

To prevent frost buildup that may affect uptime reliability, be sure to have your heat pump serviced regularly. An annual maintenance visit from a certified professional is always recommended as they will ensure any necessary repairs are completed promptly.

Troubleshooting A Stuck Reversing Valve

Troubleshooting a stuck reversing valve involves 

  • turning off the power, 
  • visually inspecting and cleaning it, 
  • checking for electrical issues, 
  • defrosting when necessary,
  • knowing when to call a professional.

Turning Off The Power

It is essential to turn off the power to the heat pump before attempting any repairs or troubleshooting a stuck reversing valve. Working on an electrical appliance without first having turned off the power can result in electrocution, fire, or damage to components.

Additionally, it could void manufacturer warranties and/or cause permanent damage not covered by insurance companies. To properly turn off the power it is best practice to shut down electricity from both the house breaker panel and outdoor surge protector if equipped.

Inspecting And Cleaning The Valve

In order to troubleshoot a stuck reversing valve on a heat pump, inspecting and cleaning the valve is an important step. 

As with any appliance, dirt and other debris can cause parts to malfunction or stick due to build-up, Inspecting and clean the valve is required. Start it by turning off all power to the unit before attempting any repair.

Once electricity is shut off, locate the reversing valve which should be connected directly to the compressor on your heat pump system. Carefully remove the cover plate from your system’s electrical connection area so that you can view and access each component more easily.

Using low-pressure compressed air or a vacuum cleaner connection tool can help provide some suction while removing dirt particles from around both ends of the reversing valve body as well as inside its valves subjectively observing tension in the spring installed therein.

Checking Electrical Connections

It is important to ensure that the electrical connection between the heat pump and its reversing valve is secure, as without these secure connections there may be no power flow to switch the unit from heating or cooling mode.

Faulty electrical connections could lead to overheating of parts, or damaging components of the heat pump, making it more difficult for them to service correctly.

To check this connection one should begin by ensuring the circuit breaker is in working order and connected properly which will protect against any major discharge of energy.

Once this is done one can inspect both ends of each wire connecting from either side and linking them securely if necessary before re-connecting all wiring into place once again.

It is also wise when checking for faulty wires to look out for corrosion along with rust on connectors which may impede proper function, in these cases, replacement may be necessary depending upon severity.

Defrosting The Unit

When a reversing valve on a heat pump gets stuck, it can freeze during cold weather as the air conditioner does not activate. To unstick it, defrosting is necessary to melt any accumulated ice or frost that has built up over time and keep the unit functioning properly.

This process should always be done in an orderly fashion by turning off the power first and then carefully removing any excess moisture from around the condenser coil before applying gentle heat via hair dryers or other warming methods.

It’s also important to make sure that no freezing water accumulates around electrical parts of the refrigeration system nearby while performing this step. 

Additionally, when undertaking defrosting of your heat pump ensure that you are using products approved for use with HVAC components as well as safety equipment such as dust masks and goggles if required.

Knowing When To Call A Professional

When it comes to a stuck reversing valve on a heat pump, knowing when to call in a professional for repairs is essential. While troubleshooting the issue can be helpful, attempting complex repair without proper knowledge or training could result in further damages to the entire system.

Some warning signs that indicate potential problems with the reversing valve may include poor heating and cooling performance, leaking refrigerant or water from components of the heat pump, loud noises coming from inside of the unit, strange odors coming from within the system.

In addition to these warning signs, if you notice frost buildup around your outdoor unit or too much liquid bypassing through pipes than normal operation requires, these are strong indicators that something might not be working correctly and wearing out faster than it should be.

How To Fix A Stuck Reversing Valve

  • Replacing the solenoid, 
  • replacing the valve, 
  • potentially hiring a professional for repairs are a possible methods to fix a stuck reversing valve on a heat pump.

Replacing The Solenoid

Replacing the solenoid is one of the solutions to unstick a reversing valve on a heat pump. Before beginning this process, it is important to ensure that the power to the heat pump has been turned off completely.

To replace the solenoid, you must first locate it by tracing its wiring all the way back to where it connects with other components in or near your unit’s control box. After disconnecting and removing any covers, remove the bolt holding down solenoid using an adjustable wrench and then pull out old piece and discard.

Put new piece in place before securing with bolts from earlier step and connecting wiring again.

Replacing The Valve

Replacing the stuck reversing valve on a heat pump can be an arduous task, and is best left to the pros in most cases.

Before attempting to replace your reversing valve, make sure you have all of the tools needed, i.e.,  heavy-duty gloves for protection; Schrader tool wrenches or vice grips; side cutters; adjustable temperature wrench set (or equivalent); copper tubing cutter(s); universal pipe raker tool; brazing rods and an acetylene torch setup with suitable tips as well as hose clamps/set screws.

Start off by turning off power from both within your home (to avoid shocks) and from outside at your outdoor unit/heat pump main disconnect box before beginning any work.

Using a set of side cutters, carefully remove two bolts that secure valves body cover onto its housing base while avoiding any extreme bends along piping stud ends that might appear after being loosened or removed completely.

Hiring A Professional For Repairs

Every heat pump requires a functioning reversing valve to control the flow of refrigerant and maintain the proper temperature inside your home. When the reversing valve becomes stuck, it can affect the system’s performance and create uncomfortable air temperatures in your house.

Attempting to fix a stuck valve on your own may lead to further damaging the heat pump or compromising its efficiency, resulting in increased costs, wasted energy, and discomfort in your home.

Licensed HVAC technicians have specialized knowledge of how a heat pump works and experience working with similar problems. They are also equipped with the right tools needed for repairs such as replacing solenoids or valves if required as part of resolving this issue quickly and safely without any risks.

Prevention Tips And Signs Of A Stuck Reversing Valve

Regular maintenance and upkeep are key to preventing a stuck reversing valve, as is familiarizing oneself with the signs of a stuck valve such as diminished cooling or heating.

Scheduling Annual Maintenance

Regular maintenance visits are an important part of heat pump ownership and help to keep the system running properly year-round as well as extending its lifespan.

A typical maintenance visit includes a thorough inspection of the reversing valve, as well as other major components such as the compressor and evaporator coil. 

During this visit, technicians will clean any dirt or debris from the outside or inside of the unit, check for wear and tear on hoses, belts, filters, etc., lubricate moving parts where necessary and inspect refrigerant levels.

On occasion, they may also tighten electrical connections throughout the unit in order to prevent electrical problems later down the line. 

Of course, these tasks focus not only on maintaining good performance but also catching any potential issues that could cause damage to components if left unchecked. Keeping detailed notes during inspections can advise homeowners when it’s time for routine repairs before problems become worse over time.

Cleaning And Replacing Air Filters Regularly

Cleaning and replacing air filters is a crucial maintenance task to keep your heat pump running efficiently. This simple chore can help ensure that your heat pump’s components, including the reversing valve, are kept in good working condition and help to maintain peak performance.

With regular replacements of the air filter, you can prevent dirt from entering the motor which can cause it to overheat due to dust-clogged motors making them work harder.

Dirty air filters require more energy consumption and lead to increased utility bills as well. Cleaning or replacing the filter every 1-3 months is recommended depending on usage frequency and will maximize efficiency and improve overall system life expectancy.

When purchasing an air filter make sure it fits properly otherwise this could affect its performance reducing airflow while still letting contaminants through into the system potentially damaging other components such as the reversing valve.

Checking Refrigerant Levels

The refrigerant levels in a heat pump are essential for its proper functioning. If the levels become too low, it can result in reduced efficiency and even damage to the compressor.

Low levels of refrigerant cause the evaporator to remove less heat from air passing over it, resulting in warmer temperatures that can be uncomfortable inside your home or building.

Furthermore, when users attempt to compensate by running their systems at higher settings (to achieve lower temperatures) this causes strain on the compressor which may lead to breakdowns and other types of costly repairs later down the line.

It is therefore important that you periodically check your system’s refrigerant level, usually about once a year during routine maintenance and fill up with more as needed.

This allows you to keep your heating and cooling system operating optimally while avoiding potential issues associated with excessive wear-and-tear due to working overtime throughout hot or cold weather seasons.

Knowing The Signs Of A Stuck Reversing Valve

A stuck reversing valve can lead to issues with a heat pump, like it being unable to switch between heating and cooling modes properly. 

Common signs include the unit not switching on when changed over from one mode to another as expected, operation in either of the two positions only, or even failure of temperatures falling within calculated tolerance ranges unless manually adjusted with switches outside the normal operating range.

These symptoms are sometimes confused for compressor failures however specialized knowledge is necessary for accurate troubleshooting.

If you’re experiencing any of the mentioned signs, take steps first by turning off all power sources related to the heat pump.


The reversing valve on a heat pump is an essential component that can cause diminished heating and cooling if it becomes stuck. With proper maintenance, failure can typically be avoided, though there are several possible causes for the valve to become stuck including frost buildup due to extreme weather conditions and dirty or clogged valves. It’s important to take the time for regular inspections of your heat pump to avoid any potential issues with its reversing valve. If you experience any symptoms of a stuck reversing valve, always try to solve the problem as soon as possible.


What is a reversing valve?

A reversing valve is an electrical solenoid that controls which direction the refrigerant moves within an air conditioner or heat pump system. It allows the unit to switch between heating and cooling modes, depending on what’s needed for the interior space.

How can a heat pump’s reversing valve become stuck?

The most common reason for a stuck reversing valve in a heat pump is due to general wear and tear over time as seals tend to fail eventually leading them to malfunction when attempting to change from heating to cooling mode (or vice versa). In addition, dirt/debris buildup, excessive dust accumulation or moisture may also be present if it hasn’t been serviced regularly contributing to additional problems. 

What steps should I take to unstick my heater’s reversing valves?

It is recommended that you turn off all power sources before starting this process as working with electricity without appropriate safety precautions in place could be dangerous for your health & property. Then inspect each component while removing any debris & accumulated material before relocating anything back together using clear directions provided by manufacturer instructions (if applicable). Additionally applying some lubrication near the seal joints of lugs/levers help ensure everything works properly afterward.

Will I need special tools before repairing my reverse valves?

Depending on how extensive repair might be needed, specialized equipment such as vacuum pumps or disposables like copper pipe fluxes will likely be required to obtain satisfactory results. However, do keep in mind that simpler tasks such as replacement O-rings might end up requiring simple hardware store items like nut drivers but just remember to consult the manual about materials for avoiding any wrong decisions.

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