C18RCH Posted February 23, 2012 Share Posted February 23, 2012 I have a fairly new (about 2 years old) compressor which gets used fairly infrequently but its suddenly started blowing the safety release valve before it gets to the cut off pressure which is causing the compressor to run constantly. Has anyone else experienced this? I've had a quick look but there doesn't seem to be anything obvious that can be adjusted. I don't want to just start messing about with something like a compressor. Cheers, Rich Quote Link to comment Share on other sites More sharing options...
Cynic-al Posted February 23, 2012 Share Posted February 23, 2012 Is it reaching pressure on the gauge (normally around 8 bar)? If not could be a faulty safety valve? They're normally set to blow above the rated pressure (8 bar?) so it should be obvious. Otherwise if it is reaching pressure its probably a fault with the switch. If its the black type with the red button on top they have an adjuster inside which may help. A clean and light oil might help too. Check the connections, it should be connected to the tank side but also have a pipe to the pump side of a none return valve which is used to unload the line so that the pump isn't starting under pressure. In cold weather mine goes stiff and won't turn on without a tap. Or just buy a replacement. Quote Link to comment Share on other sites More sharing options...
C18RCH Posted February 24, 2012 Author Share Posted February 24, 2012 No, it's not reaching the correct pressure. The PRV blows before it gets there and so never reaches the correct pressure. Quote Link to comment Share on other sites More sharing options...
sean f Posted February 24, 2012 Share Posted February 24, 2012 Most PRV's are just a sprung loaded plunger, when the pressure is greater than the spring strength it blows off. It is possible the spring in yours is weak, corroded or broken. They are readily available from the likes of machine mart and other similar stores for about £5, just unscrew and fit a new one (after checking the tank is fully depressurised!). I wouldn't bother trying to "fix" an old one, it is a safety device and at that price just not worth the potential risk. Quote Link to comment Share on other sites More sharing options...
jbs Posted February 24, 2012 Share Posted February 24, 2012 you can get spares from SIP and Sealey off the net: as I had to buy a new starter switch for mine-then found out it was the NRV on the small copper tube that needed cleaning out as it had small pieces of rust blocking the plunger so it was releasing the air out of the switch and I religiously drain my tank at the end of the day too and It still managed to go rusty on the inside of the tank Quote Link to comment Share on other sites More sharing options...
C18RCH Posted February 27, 2012 Author Share Posted February 27, 2012 Sorted now. Thanks for all the replies. New PRV fitted and cut off pressure reduced to just under 8 bar using an adjuster that was under the on off switch cover. Cheers, Rich Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.