Mastering the Diverter Valve: The "Traffic Cop" of Your Fridge

SAFETY MESSAGE: Handling refrigeration diverter valves involves working with the sealed system and delicate electrical solenoids. Always unplug the appliance before testing. If the valve requires replacement, it must be performed by a certified technician to avoid refrigerant leaks or flammable gas hazards.

If you have a "combined" fridge-freezer with only one compressor, the Diverter Valve (or Step Valve) is the unsung hero. Its job is to act as a traffic cop, switching the flow of refrigerant between the fridge evaporator and the freezer evaporator depending on which section needs cooling.

Key Diagnostic Tips:

• The "Half-Cold" Symptom: The most common sign of a stuck diverter valve is when one compartment (usually the freezer) is ice-cold, but the other (the fridge) is warm, even though the compressor is running perfectly.

• The Clicking Sound: When you first plug the fridge in, you should hear a faint "click-click-click" from the back. This is the valve initializing. If it’s silent or making a loud grinding noise, the internal gears or solenoid may have failed.

• Pulse Testing: These valves are controlled by DC pulses from the main PCB. If the valve isn't switching, the issue could be the valve itself or a faulty signal from the control board.

Improved Repair Strategy:

1. Check for "Default" Mode: Most valves are designed to default to the freezer if they fail. If your fridge section is warm but the freezer is -18°C, the valve is likely stuck in the "A" position.

2. Magnet Test: Since these are solenoid-driven, a strong magnet can sometimes be used by technicians to manually "force" the valve to switch to see if the blockage is mechanical or electrical.

3. The Coil Test: Use a multimeter to check the resistance of the valve coil. An "Open Circuit" (OL) reading means the solenoid has burnt out and the entire valve assembly needs professional replacement.

4. Avoid Debris: Diverter valves have very tiny internal ports. If you’ve recently had a compressor burnout, carbon soot can clog the valve. Always ensure a high-quality filter drier is installed to protect this component.

This is used in more expensive models where a secondary evaporator is used to cool a second fridge freezer cavity, when the temperature reach a set point then the diverter valve with operate and allow refrigerant to flow to the second evaporator as well.

These valve use either synchronous motors or just a simple solenoid valve to open them when they are signalled.

What can go wrong with diverter valves 

If the secondary fridge freezer cavity is not getting cooled  but the primary is functioning ok then its a god sign the diverter valve may be faulty and its best to test it prior to replacing any parts as it could be a control issue and not a faulty valve, normally the fridges with these are fitted with self diagnostics and servicing modes where you can manually operate the valve to ensure all control function are fine.

Study up on the model your working on and see what information is available on the service modes and diagnostics.

The solenoid valves have a coil of wire and are easy to test just take a resistance measurement over the two terminals. Reading can be from 1-4 ohms but if you get Ol then the winding in damaged and needs replacement. Replacement means recovering and recharge of the system.