clarke shhh air 2/9 - leaking?

[Joe2003]

Hi

I have been given a clarke shhh air 2/9. When I power the unit on I get air escaping from a small brass tube underneath the plastic housing that holds the on/off switch. The brass tube has a hole purposely drilled in it, the air that escapes seems to be fairly oily.

Sorry for my incompetence, I can get a picture later. The compressor hasn't been used for months, oil levels all seem fine. I guess some valve is ceased and needs cleaning/replacing?

Thanks for any help you can give!

 

[Wendelspanswick]

I don't know that specific compressor but some small compressors are designed as 'constant bleed', they don't have an unloaded valve so the hole is designed to stop the compressor stalling at full pressure.

 

[rtbcomp]

Welcome to the forum.

That sounds like the unloading valve.

It could be jammed due to oil, or it may be the wrong type - does it look as though the switch has been changed at some point?

There are two types of unloading valves :-

1) closes as soon as the switch is set to "on".
2) closes when the pump has built up a bit of pressure, usually about 20psi; takes a few seconds depending on pump output and tank size.

The Shhhhhh compressors should have the type 1 valve, they are not constant bleed.

A picture would be useful.

 

[Joe2003]

Thanks for the help. I will try to get a picture later. Its my dads compressor, its only 8months old and no parts have been replaced. It definitely didn't do it before, I can understand it might trip in every now and then, but this is constant.

 

[Joe2003]

Now I have some names to google, it appears you have already answered the question for someone else:-

http://www.mig-welding.co.uk/forum/threads/shhh-2-9-leaking-air-and-oil.40780/

It sounds the same issue as this, thanks for the help rtcomp

 

[rtbcomp]

Let us know the outcome - it's always useful to know how problems were fixed.

 

[Joe2003]

I fixed this, just thought I would update to let others know.

The brass tube has a valve that pushes a pin up to shut the compressor off when pressure has been reached. I assume that after long periods the rubber gasket in this brass tube stiffens and is constantly open, meaning oil and air pass through the exhaust point on the tube constantly

I fixed by removing the small grub screw that holds the brass tube in place. Then take the tube in your hand and press the pin at the top down and release (like a clicky pen). Turn the compressor on and constantly click the pin up and down to loosen the valve. I did this for 5 mins, then reassembled and let it build pressure. Vent the reservoir and repeat until the valve operates correctly.

 

[rtbcomp]

The brass tube has a valve that pushes a pin up to shut the compressor off when pressure has been reached.

I don't think so.

I think the Shhhh range uses the same pressure switch as the piston types, if so here's a diaphragm in the switch which takes it's pressure from the tank and when the switch turns off it pushes the pin down to release the pressure in the pipe between the pump and the non-return valve on the tank, via the thin pipe.

When the switch goes back to ON the pin will rise under spring pressure (or pressure from the tank - depending on the type of valve) to close the valve. It sounds like your valve was sticking due to gunge and working it freed it up.

There's isn't a diaphragm in the unloading valve, it's a needle valve.

If your's is different I'd be interested to see some pics.

Still, I'm glad you fixed it!