Liquid solenoid refrigeration valves are found in many commercial and industrial systems.
They are used to isolate the refrigerant in the receiver.
A correctly operating valve is essential in all pump down applications
What about installation?
When installing a liquid solenoid valve, always check the direction indicator. There's usually an arrow on the valve body.
If the valve is installed with the wrong flow, it will not work correctly.
Another consideration must be taken when the valve is brazed into the system. Too must heat can cause damage.
I always disassemble the valve, protecting the internal components.
Disassembly also lessens the amount of heat needed to reach the proper brazing temperature.
What are common problems and repairs when using these refrigeration valves?
1. Refrigerant Leaks: Most refrigerant leaks occur when gaskets become worn. Vibration can also cause the valve body to loosen, creating a leak.
2. Trash and Debris: Any small particles such as copper shavings, brazing oxidation, or filter-drier material, can cause the valve to stick open.
3. Wrong Installation: As mentioned above, check the flow direction of the valve.
4. Wrong Size: Make sure the proper size valve has been installed. If the valve is too small, it restricts the refrigerant flow and decreases the system capacity.
5. Worn Components: Repeated opening and closing over many years wears out the sealing ring on the piston, it begins to stick.
6. Bad Coil: The valve coil can go out, like any electrical component.
7. Wrong Voltage: Make sure the correct voltage coil is installed. A 24v coil on a 240 volt control system will quickly "go up in smoke!"
Wondering if the valve is energized?
Simply touch the coil. An energized valve coil will be warm when touched. You can also feel a slight vibration.
If you have your amp meter handy, open the jaws and rest them against the coil. When energized, the meter will register a reading.
You can also hear the valve when energized. It makes a distinct clicking noise as the piston is pulled up by the coil.
But when they stick open on a pump down sytem, the results can be disastrous. The condensing unit continues to run. The thermostat is useless.
Perishable product can be ruined by extremely low temperatures.
What's a solution?
Install an alarm system. A loud buzzer or bell that sounds when a preset low limit is reached. It gives one "peace of mind."
Liquid solenoid refrigeration valves last years and years. It's amazing when you consider how many times they open and close!
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