Speedaire 5Z405A - relief valve continuously blows and compressor does not reach shut-off pressure.

by Chris
(Buckeye, AZ)

I have a Speedaire 5Z405A twin cylinder compressor. One of the 75PSI reliefs for one outlet tube continuously relieves air as the compressor tank pressure increases over 100psi. I switched the relief with the other side (cylinder) and the problem stays with the cylinder not the relief valve. When shutting off power there is a clicking noise from the crankcase until you manually relieve the pressure on the cylinder with the relief that blows. Is this a valve problem in the cylinder itself?

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Bill says...

Chris... if the PRV that's set for 75 PSI is blowing off when pressure in the tank reaches 100 PSI, then some of that tank pressure is back-flowing and pressurizing the line to blow off the PRV.

I'd look to the intake valve on the cylinder with the line that has the blowing off PRV.

Get that fixed, and then look to the unloader valve for a possible resolution to your compressors other problem.

Cheers,

Bill