safety valve issue

[miggymarky]

My compressors safety valve keeps blowing off.originally the compressor was blowing off at 150 psi,so I thought I would adjust it to 120psi,and still blowing off.anyone know my problem,is there something I'm missing.when it blows off,it lasts for about 1 minute then starts up again and repeats the cycle.

 

[the snooper]

spring could have become weak buy a new safety valve that should cure it unless the compressor spec states it should reach a lower pressure then switch off

 

[brightspark]

if it is the safety valve that is set at 150 psi and its blowing off and u think its blowing off premature it will blow off even quicker if u lower its pressure to 120 psi its supposed to blow of if the tank fill exceeds the pressure switch setting by about 10 psi

 

[Bill Edwards]

Assuming you don't have a very faulty pressure gauge (yes, I've seen them to be that far out) and that the compressor is meant for this pressure (are you sure it's not meant to stop at say 100psi, many are?) then the safety valve is either wrong or faulty. Whichever, the fix would be the same.

Brightspark, I think he adjusted the cutout pressure, not the relief valve pressure.

 

[brightspark]

Assuming you don't have a very faulty pressure gauge (yes, I've seen them to be that far out) and that the compressor is meant for this pressure (are you sure it's not meant to stop at say 100psi, many are?) then the safety valve is either wrong or faulty. Whichever, the fix would be the same.

Brightspark, I think he adjusted the cutout pressure, not the relief valve pressure.

 

[simplysimon]

it sounds like the motor cut-off valve has gone faulty and allowing the pump to keep making pressure

 

[miggymarky]

it sounds like the motor cut-off valve has gone faulty and allowing the pump to keep making pressure

So how do i sort this problem.there is a red cap on the side of the pressure switch,and a small slotted screw on top by the but that adjusts the spring.what are these for?

 

[simplysimon]

is this for your clarke? the red cap could be the pull/push on/off switch but more likely to be the pressure relieve valve if this is the valve thats been blowing off.
I'd take the switch assembly off the compressor and strip it down and clean it with some carburettor cleaner, not sure if this type has a ball bearing under the spring or it could be the electrical contacts have welded themselves together.

its probably a good idea to count how may turns it take to remove the valves for reassembly purposes.

you can get complete replacement switches for under £20

http://www.ebay.co.uk/itm/AIR-COMPR...E-PHASE-THREE-PHASE-20AMP-VALVE-/171099843202

 

[miggymarky]

is this for your clarke? the red cap could be the pull/push on/off switch but more likely to be the pressure relieve valve if this is the valve thats been blowing off.
I'd take the switch assembly off the compressor and strip it down and clean it with some carburettor cleaner, not sure if this type has a ball bearing under the spring or it could be the electrical contacts have welded themselves together.yes mate the Clarke,the on/off button is on top,so the other one is the prv I assume.

its probably a good idea to count how may turns it take to remove the valves for reassembly purposes.

you can get complete replacement switches for under £20

http://www.ebay.co.uk/itm/AIR-COMPR...E-PHASE-THREE-PHASE-20AMP-VALVE-/171099843202

 

[brokenbiker]

may be you just need to tighten the sckrew/spindle holding the spring.

second forum post and a shameless plug for your own company...not sure that's allowed.

back to the op, my father had a comp that used to do this, i think he ended up changing the cut off switch as this was dead and the tank just kept filling until it hit the safety, dumped all the pressure then started filling again. The pump was still going while it was dumping the contents of the tank too

 

[the snooper]

in the ebay link above it states that the safety valve is 10 bar which works out at under 150 psi so if yours is blowing off at 120 when the compressor actually cut out briefly the safety valve has to be faulty