How do I know that I have or don't have a non-relieving air coupler?

by Len
(Boston, MA)

My manual states that I should not use a non-relieving air coupler on my nailer. I bought a set of 5 couplers and fittings for my snap-on nailer. How do I know that the coupling is the correct one for my devise? Thanks.

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Bill says...

Len, I think a non-relieving coupler is a "checked coupler". A checked coupler is one that, when the mating connector is removed, holds an air charge behind it.

If you have an air charge in the nailer, even if the air hose is gone, then you have an air charge in the gun, and it could be fired unsafely.

The way around this issue, of course, is to only have a connector in the handle of the air nailer, and it's the air line that has the "non relieving" or checked coupler.

Then, when you unplug the coupler from the gun, any air in the gun will bleed out to atmosphere, while the air line will not bleed air because of the checked coupler on the end of it.

Short answer, only thread air connectors into the supply port of your air tools, never use a coupler, as most are non-relieving.

Cheers,

Bill