Bypassing the defrost board on a heat pump can be a simple solution to allow cooling when the system is stuck in heating mode. By following these 9 easy steps, you can bypass the defrost board and enable your heat pump to operate in cooling mode, even during defrost cycles.
Check the Reversing Valve
The reversing valve is a critical component in a heat pump system, responsible for switching between heating and cooling modes. Before attempting to bypass the defrost board, ensure that the reversing valve is not stuck in the heating position. This can be done by visually inspecting the valve or by using a multimeter to check for continuity across the valve terminals.
Locate the Defrost Board
The defrost board is typically located near the outdoor unit of the heat pump. It is responsible for controlling the defrost cycle, which prevents ice buildup on the outdoor coil. Identify the exact location of the defrost board to access the necessary terminals.
Identify the Terminals
On the defrost board, locate the terminals related to the reversing valve. These are usually labeled as ORV (Outdoor Reversing Valve) and CRV (Compressor Reversing Valve). Make a note of the terminal locations and the wiring connections.
Disconnect the ORV Terminal
Carefully disconnect the wire connected to the ORV terminal on the defrost board. This will prevent the board from controlling the reversing valve, allowing you to bypass its function.
Connect the ORV Terminal to the Contactor
Take the wire that was previously connected to the ORV terminal and connect it directly to the contactor. This will ensure that the reversing valve is constantly energized, forcing the heat pump into cooling mode.
Check the CRV Terminal
Ensure that the CRV terminal on the defrost board is still connected. This will maintain the other functions of the board, such as fan and compressor pressure switches, which are essential for the proper operation of the heat pump.
Test the System
Turn on the heat pump and set it to cooling mode. The system should now blow cool air, indicating that the bypass has been successful.
Monitor the System
Keep a close eye on the system to ensure it is working properly. If the defrost board was bypassed correctly, the heat pump should continue to blow cool air even during defrost cycles.
Note the Limitations
It’s important to understand that bypassing the defrost board will prevent the heat pump from switching to heating mode. This means the system will not work during winter months when heating is required. The bypass should only be used as a temporary solution to allow cooling when the defrost board is malfunctioning.
Technical Specifications:
- Voltage: 24V AC
- Wire connections: ORV terminal to contactor, CRV terminal to defrost board
- Components involved: Defrost board, reversing valve, contactor
By following these 9 easy steps, you can effectively bypass the defrost board on your heat pump and enable cooling mode, even during defrost cycles. However, it’s crucial to understand the limitations of this bypass and to seek professional assistance if the issue persists or if you are unsure about the process.
References:
- How did my technician bypass the defrost board for cooling?
- Heat Pump Troubleshooting- Defrost Board Testing and Bypass for Cooling
- How to bypass a defrost heat pump board to allow cooling
- How to disable defrost completely in a Carrier Infinity Heat Pump
- How to bypass a Defrost Heat Pump Board to allow cooling – YouTube
Hello…I am Manjula Sivapuri. I have completed my graduation in Chemistry. Currently working as a Chemistry Subject Matter expert in LambdaGeeks. My keen interest in chemistry has brought me to this platform to share my knowledge on the subject. I hope my work will make you understand the topics well.
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