Refrigeration Compressors Whistling?
Better Listen!

Refrigeration compressors make some very weird sounds. They hum, click, clack, hiss, scream... Each sound can be very important.

To the trained ear, they tell a tale. Many times I know what's wrong before reaching the compressor!

Ever heard a compressor whistle?

Sometimes the whistle is very soft. You have to shut down near by refrigeration compressors to hear.

Sometimes it is so loud you'd think someone stepped on a cat's tail!

Where is it coming from? Trying to isolate it can be frustrating. But almost every time it's coming from the compressor heads.

The customer complains that the cooler is just not getting cold. It never reaches the desired temperature.

The condensing unit is running. But the heat from the condenser is not very warm.

You reach out and touch the compressor heads. Two of the three heads feel normal. A little cool on one side and very hot on the other.

But one of the heads is hot on both sides!

Grab those refrigeration gauges. High side pressure is a little low. Low side pressure is much higher than normal.

Time to shut off the condensing unit.

What that??? As you place your ear over the heads you hear it! A very faint whistling noise!!!

So, what's whistling? The whistling sound is refrigerant gas escaping from the high side of the valve plate.

But which of the three plates? Yep, you're right!!! It's the compressor head plate that was hot on both sides. Start there.

While removing the head and plate, look closely. Notice any pieces of metal? Missing valve reeds? Excess oil in the cylinder? Heat discoloration of the metal?

If so, then you've found it. It was a bad valve plate.

Didn't see any of the above? Look very closely at the gasket. Bet you find a piece missing between the high and low sides of the head.

Just a very little section is all it takes!!!

New plate or gasket installed and you are ready to go!!!

Not so fast!!!

What caused the failure?

Chances are, liquid refrigerant flooded back to the compressor. It will break valves and blow gaskets every time. Can also bust a piston!

Find the cause and repair it, or you'll hear refrigeration compressors whistling their awful song again and again.

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