Air regulator builds pressure slowly

by roy
(brant, ny)

26 gallon tank fills to 155psi and air regulator also reads 155psi when fully open. while using blow gun air pressure reading on regulator drops down to 20 psi after a few seconds then very slowly builds pressure back to around 150 psi. why doesn't pressure jump back up quickly after i stop using blow gun?

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Bill says...

Hello Roy,

A compressed air blow gun uses huge amounts of compressed air. So much so that you are (I believe) almost emptying your tank in a very short time.

You don't indicate your compressor size. A 26 gallon isn't a huge tank, yet, for example, a 1 HP compressor putting out the max possible of 4 CFM of air at 90 PSI will take minutes to fill the tank pressure back up, which is why your regulator is showing increasing pressure so slowly.

Why are you using that high a pressure to blow off? If it's not necessary, turn your air pressure setting down as far as you can and still do the work with the blow gun. Then your charge of air will last longer.

Also, you draw the air down to 20 PSI and then stop blowing air and the tank takes a long time to fill. I am assuming that your air compressor cuts in at around 80 PSI or so? If not, that may be part of your compressor problem.

Cheers,

Bill