DIY Repair: How to Replace a Heat Pump Reversing Valve

Posted: June 21, 2024

Heat pumps are an essential component of HVAC (heating, ventilation, and air conditioning) systems, providing both heating and cooling functions for residential and commercial spaces. The role of the reversing valve in a heat pump is pivotal to its operation. It enables the heat pump to switch between heating and cooling modes. The HVAC reversing valve essentially determines whether the heat pump operates in heating or cooling mode, making it a critical component for year-round comfort and energy efficiency. When the reversing valve malfunctions, it can lead to issues such as the unit not switching modes, reduced efficiency, unusual noises, and temperature inconsistencies. Considering the importance of the reversing valve on heat pump, it's vital to address any problems promptly to ensure the proper functioning of the HVAC controls

What is a reversing valve?

A reversing valve, also known as a four-way valve or changeover valve, is an essential component of a heat pump system that allows the device to flip between heating and cooling modes. This valve directs the flow of refrigerant throughout the system, deciding whether the heat pump is in heating or cooling mode.

Functions of a reversing valve in a heat pump

The reversing valve plays a crucial role in the operation of a heat pump by reversing the refrigerant flow. 

  • Heating mode: In heating mode, the reversing valve directs the refrigerant flow, absorbing heat from the outside air (even when it is cold) and releasing it within the building to give warmth.
  • Cooling mode: When the heat pump is in cooling mode, the reversing valve alters the refrigerant flow direction. Heat from inside the building is now absorbed and discharged outside, so cooling the interior space.

What are the types of reversing valves?

Type of reversing valve


Standard reversing valve

Found in traditional split-system heat pumps and some packaged units. Reverses the flow of refrigerant to switch between heating and cooling modes.

Mini split reversing valve

Specifically designed for ductless mini-split heat pump systems. Controls refrigerant flow to facilitate both heating and cooling operations within the mini-split unit.

2-way reversing valve

Typically used in some older or simpler heat pump systems. Allows refrigerant flow to be redirected between the indoor and outdoor coils for heating and cooling.

3-way reversing valve

Commonly employed in commercial and industrial applications. It enables the diversion of refrigerant flow among multiple heating and cooling circuits, providing flexibility in system operation.

4-way reversing valve

Integral to reversible heat pumps and air conditioning units. Four way reversing valve controls refrigerant flow direction for both heating and cooling modes, offering versatility in system functionality.

Refer: How Much Will A Heat Pump System Cost?

Signs of a faulty reversing valve

Signs of a faulty reversing valve_PartsHnC

Tools and materials needed for replacing a reversing valve

Essential Tools for Replacing a Heat Pump Reversing Valve: Before attempting to replace a heat pump reversing valve, ensure you have the necessary tools and equipment. 

  • Screwdrivers: Flat-head and Phillips-head.
  • Wrenches: Adjustable or specific size.
  • Multimeter: For measuring electrical current, voltage, and resistance.
  • Refrigerant recovery machine: For safely recovering and storing refrigerant.
  • Flaring tool: For creating proper flare fittings.
  • Tube cutter: For cutting copper refrigerant lines.
  • Adjustable pliers: For gripping and turning pipe fittings.
  • Socket set: For removing fasteners or bolts.
  • Torque wrench: For properly tightening fittings.
  • Brazing/welding equipment: If brazing or welding is required.

Replacement part for heat pump
When obtaining the correct reversing valve for a heat pump model, it's essential to ensure compatibility and fit. 

Safety equipment

  • Safety glasses: To protect eyes from debris and refrigerant.
  • Gloves: For hand protection from cuts and refrigerant exposure.
  • Work boots: Sturdy boots with toe protection.
  • Protective clothing: Appropriate work clothing to protect skin and prevent exposure to hazardous substances.

A step-by-step process for replacing the reversing valve

  • Shut down the system

Turn off the heat pump by adjusting the thermostat, and disconnect the power supply at the circuit breaker to ensure safety during the repair.

  • Recover the refrigerant

Attach a refrigerant recovery machine to the system as per manufacturer instructions to safely recover the refrigerant from the heat pump. Follow proper guidelines for handling and storing the recovered refrigerant.

  • Access the reversing valve

Remove the access panels or covers on the heat pump unit to expose the reversing valve assembly. The valve is typically located near the compressor and refrigerant lines.

  • Disconnect electrical connections

Carefully disconnect any electrical wires or connectors attached to the old reversing valve. Take note of the wire connections or label them for later reference.

  • Remove the old reversing valve

Use appropriate tools such as wrenches, to loosen and disconnect the old reversing valve from the refrigerant lines. Take care to prevent any refrigerant leaks during this process.

  • New reversing valve replacement

Position the new reversing valve in place and securely connect it to the refrigerant lines using fittings and appropriate sealing materials based on manufacturer recommendations.

  • Reconnect electrical connections

Attach the electrical wires to the corresponding terminals on the new reversing valve as per the labeling or notes taken during disconnection.

  • Evacuate and recharge the system

Use a vacuum pump to evacuate any air and moisture from the system. Once evacuated, recharge the heat pump with the correct type and amount of refrigerant, following manufacturer specifications.

  • Test the system

Restore power to the heat pump and test its operation to ensure the new reversing valve functions correctly. Verify that the heat pump switches between heating and cooling modes as intended.

Checkout: How Much Does It Cost To Install A Heat Pump?

Troubleshooting reversing valve in a heat pump is a complex task that requires careful attention to detail and adherence to safety protocols. However, it's essential to prioritize safety, especially when handling heat pump parts. If you are unsure about any aspect of the replacement process, or if you encounter challenges during the repair, seeking professional assistance from a qualified HVAC technician is highly recommended. 

At PartsHNC, you can find a wide selection of heat pump replacement parts. One popular manufacturer of heat pump parts is Carrier. The Carrier reversing valve, in particular, offers a range of commercial designs to work efficiently and effectively in high-traffic kitchens.


How to unstick a reversing valve on a heat pump? 

Professional intervention is often required to unstick a reversing valve. Applying gentle tapping or controlled electrical impulses may help, but it's advisable to consult an HVAC technician.

Heat pump reversing valve replacement cost? 

The cost varies based on factors like the type of heat pump, labor, and parts. On average, the replacement cost can range from $500 to $1500, including labor and parts.

How to bypass reversing valve?

Bypassing a reverse valve coil is a complex task and may not be advisable. It's best to consult with a qualified HVAC technician for proper diagnosis and repair.