My safety valve keeps popping off well below the psi max operating level.

by Joe Mistretta
(Davenport, FL)

So I have a 5 gal. pancake compressor Central Pneumatic that is a 150 psi max compressor. I'm using it to fill a pressure pot for pressure casting molds. The pressure pot is also a Central Pneumatic rated for max working psi of 60. The pancake output gauge is set to 50 psi. The pressure pot's safety valve keeps popping off at or below 40 psi. I need it to stay at 40-55 psi for proper pressure molding and pressure casting. Why is the safety valve popping too soon and how can I fix it? An I adjusting something wrong or doing something wrong? Sorry I don't have photos.

Comments for My safety valve keeps popping off well below the psi max operating level.

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Feb 17, 2017
safety valve keeps popping off
by: Doug in s.d.ca.

Are you not using the regulator/gauge that comes with the pot?

I ask because that would give assurance that the pressure is, in fact, what you believe it is.

If you have just one gauge, it could be giving a false reading.

Otherwise, what Bill said.

Feb 15, 2017
PRV on pressure pot letting go
by: Bill

Well Joe, I'm not pro painter, and don't use a paint pressure pot in my day to day work.

I have to wonder though, have you removed the PRV and rinsed it with solvent to try and solve the problem?

If contamination gets into a PRV, it can sometimes act as a lubricant, and reduce the cracking pressure.

If cleaning it doesn't work, and if the PRV continues to crack open at below the normal pressure, I'd replace it.

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