Abac compressor safety valve

[hunter27]

Hi
My Abac compressor has/had a safety valve that I tried to dismantle as the "push on pipe" slid off when I tried to undo the valve to see if I could make a better connection the brass valve sheared off .
I cannot understand how this valve works.
The threaded end connects to the pressure tank and the flex/push on end connects to the pipe between the compressor and the tank but is before a one way valve see picture.
I know that if the pressure got to much the valve would open against the spring but the thing that I can't understand is that the push on pipe is pushed onto a solid stub with no hole through it at all ?. with the valve capped off the cut out works ok and when the compressor turns itself off there is no pressure at the flexi pipe?
I fully intend fitting a new safety valve but do I need to get one that incorporates the flexi pipe ?

Thanks
Pete

 

[rtbcomp]

That looks a bit strange.

Normally the flexible pipe from the non-return valve fits onto an unloading valve in the base of the switch, not one screwed into the connection between the tank and the switch.

 

[hunter27]

Hi rtbcomp
Thanks for your reply I am sorry if my description was misleading the safety valve does screw into the base of the switching valve but seems to be at cylinder pressure.
What I don't get is what use is a flexi air pipe terminating on to a solid stub that can never pass air through it ?

Just a thought I bought this compressor second hand and wonder if that pipe had just been pushed onto the end of the safety valve spindle. I was assuming that it was piped through. This compressor is not quite the same as mine but the safety valve looks the same but without the pipe pushed on.

Pete

 

[shenion]

The pipe should go to the pressure switch. Looks like they stuck it on the safety valve to keep the pipe from leaking.

 

[rtbcomp]

The pipe should go to the pressure switch. Looks like they stuck it on the safety valve to keep the pipe from leaking.

Yes. When the compressor reaches pressure and stops do you get a definite hiss from the switch?

It sounds like you may have two problems, 1) a broken safety valve, these are standard items, and 2) broken or missing unloading valve. You can get replacements but by the time you've faffed around finding the right one you may as well get a new switch.

 

[hunter27]

Thanks
I have never heard an unloading hiss.
The funny thing is that I have had the compressor for about a year now with no trouble at all. Maybe the push on pipe was leaking just enough to drop the pressure in the head when the motor stops but not enough to affect the filling of the tank. I will have a better look tomorrow to see if there are any other connections under the control valve where this pipe should connect.
Thanks again.
Pete

 

[hunter27]

Just a quick update
I have extended the flexi pipe to (a previously unused hole) I found under the unloading valve and I now do get a hiss when the compressor unloads
I have also ordered a new safety valve.
Thanks for the help and advice.
Pete

 

[rtbcomp]

Great, it's always nice to hear that a problem has been solved.