What is This Part

[dale farley]

I noticed this device on my air compressor is leaking from the hole as shown in the picture. I assume this is some kind of pop-off valve, but I don't know for sure. Is it something I can clean up and lubricate and get to working again, or do I need to replace it?

[sawdust_128]

I noticed this device on my air compressor is leaking from the hole as shown in the picture. I assume this is some kind of pop-off valve, but I don't know for sure. Is it something I can clean up and lubricate and get to working again, or do I need to replace it?


It appears to be either a safety over-pressure release valve or a moisture blow out valve. Call Thomas 800-848-7735 to see if they have a rebuild kit.

Personally, I'd replace it.

[Kenneth Brewer]

It is a relief valve and not a moisture relief valve, otherwise it would be on the bottom or have a tube to the bottom (which I have never seen personally) of the vessel. I agree - replace it, I doubt there is a rebuild kit for it anyway. Good luck. Should be easy, now that you gotten to it.

[dale farley]

I am sure it isn't the moisture valve. As you said, it is on the bottom. I hit a siwtch to activate the moisture drain valve.

[dale farley]

Thomas finally called me back, and it is a check valve. They are sending one to me. Thanks for the input.

[sawdust_128]

Thomas finally called me back, and it is a check valve. They are sending one to me. Thanks for the input.


What exactly does it check? Does it keep the system pressurized when you release and drain the tank? Interesting.

[Joe Cannarozzi]

And an adjustable one at that.

[dale farley]

They didn't tell me what it checks; maybe it prevents the air from flowing backwards in the supply line.

[Kenneth Brewer]

I hit a switch to activate the moisture drain valve.

Uh oh, you are going to get picked on for that statement.