hissing safety valve

[miggymarky]

Changed the gaskets now on my compressor and all working again,but now when it gets to about 50psi it starts to leak a bit from one of the small holes on the safety valve,and never did it before gaskets were done.Any ideas folks.

 

[rtbcomp]

A bit of dirt in the valve, valve needs adjusting, faulty pressure gauge??

Has the valve got a ring on it so you can pull it? If so give it a go, it might clean the seat up.

 

[miggymarky]

Ok cheers rtbcomp,but why now since its had new gaskets.

 

[rtbcomp]

Coincidence, bit of foreign matter from the old gasket found its way in there.

Did it cut off before you fixed the gasket? If not maybe it's now cutting off at a pressure higher than the safety valve setting, the safety valve is just doing its job.

 

[miggymarky]

Just took it apart and seems ok so don't know what to think.

 

[rtbcomp]

Fix it with a new one - they're not expensive. Get one rated at 1 bar over safe working pressure of your tank.

 

[madkayaker]

Fix it with a new one - they're not expensive. Get one rated at 1 bar over safe working pressure of your tank.

You want the blowoff valve to be less than safe working pressure on tank so the valve goes before the tank goes pop! Get one just above the cutout pressure of the unit. Normally 140 psi with a cutout pressure of 125psi.

 

[rtbcomp]

The SAFE working pressure (SWP) is the pressure the tank works SAFELY at. The test pressure is 2 or three times that, and the POP pressure higher still.

There's no point in having the safety valve blowing off at a pressure less than the working pressure.

My 10 bar tank has an 11 bar safety valve.

There's no point in getting a safety valve that's just less than the set cut-off because the latter is variable. Rather you set the switch cut-off to be less than or equal to the SWP.

 

[madkayaker]

That's not what the latest pressure inspector to visit site for statuary inspections said

 

[rtbcomp]

Machine Mart sell an 11 bar safety valve, whereas their industrial compressors have a maximum SWP of 10 bar. If you needed a safety valve less than the SWP they'd sell 9 bar safety valves, or their compressors would have an SWP of 12 bar.

 

[rtbcomp]

From here

http://www.compressedaircentre.ie/safety-valve-pressure-relief-valve-p-122.html#.Udhhrax0mP8

3- Safety valves are usually set about 10% above the safe working pressure but this can vary slightly.