Recurring fault on Clarke compressor

[buckers]

My Clarke 25 compressor has started blowing off on the relief valve quite regularly now. It's working ok one moment, then suddenly vents pressure, then stops venting, and charges up again, then vents. From experience, I know that this is caused by foreign bodies getting stuck under the rubber valve in the valve assembly that is attached to the side of the receiver tank, breaking the seal, and allowing the compressor to function correctly (by blowing off!!)

I'm anticipating exploratory work into the compressor assembly to workout what's going on. The bits that block the valve are black, and do not seem to be metal. ie I seem to be able to crush them in my fingers, but they are quite hard, and they're only small, about 1/8" max.

Anyone any experience of this and any pointers as to where I should look first.

Using the compressor in my house garage, so not too dusty, etc, and it's only used for spraying small objects.

Help!

Buckers

 

[rtbcomp]

Welcome to the forum.

Do you mean the safety valve or the small valve in the pressure switch, connected to the thin pipe that goes from the non-return valve on the tank?

Does it switch off when max. pressure is reached? If not maybe the pressure switch is faulty/mal-adjusted.

If it doesn't reach max pressure the srping on the safety valve may be a bit weak.

The bits in the non return valve are most likely bits of rubber from the valve itself or carbon from the pump, oil will burn on to the valves if the rings are a bit worn.

 

[buckers]

Hi, thanks for the extremely quick reply.......

You'll have gathered that I'm not too up-to-speed with compressor parts, but this is the valve where the bits get deposited on the rubber seal/valve..



And this is what the bits look like....



When the compressor runs normally, it gets up to pressure fine, stops, and then kicks back in when it should. When this problem occurs, the compressor runs, then the valve is forced open by the bits, (or more correctly, cannot close), and it vents, then the compressor kicks in again, ad infinitum.....

The bits, as you say, are probably carbon, as opposed to the motor breaking up. Does this mean a strip down and de-coke ?

Thanks once again

Phil

 

[rtbcomp]

The top picture is the non return valve (NRV), the thin plastic pipe is the unload pipe which connects to the unload valve in the pressure switch.

If the NRV gets jammed open when the motor stops air will drain out of the unload valve continuously, is this what happens? I'm not clear about what happens under fault conditions, does the motor run all the time or does it stop & start?

I'm still not clear if you mean the safety valve or the unload valve when you say relief valve.

There are some pics of compressor bits here

http://www.mig-welding.co.uk/forum/album.php?albumid=900

 

[buckers]

If the NRV gets jammed open when the motor stops air will drain out of the unload valve continuously, is this what happens?

Yes, this is what is happening. I think you've answered my question, and informed me as to what the part is called.............the NRV.
Thanks again

 

[rtbcomp]

That's good - from your OP I thought the motor was running all the time and the safety valve was opening.

 

[buckers]

No, it was just these little bits of carbon (now I know and am not so worried).

I am having a "compressor-fix" day.

The Ranger is my main one, and I've been given a Warrior (minus a few bits), so am ordering bits for that, as a stand by.......

I only got these 'cos my original one, (new), a Marksman (s**t), failed after 9 months. Seller won't play ball and makers don't respond !!
That won't build up pressure past about 30psi, so I'm about to strip it down. Done a bit of reading and suspect inlet system, ie reed valves.

Hmmph

 

[buckers]

Right, think I've found the culprit. There's a thick (about 2mm) gasket on the head that seperates the inlet air from the compressed air that gets fed to the tank. This is breached and I suspect leaking outlet air to inlet air. There's no way I'll be able to get the original part, so does anyone know what sort of material I can use to make a new one? Seems a sort of rubbery compound, obviously not an instant gasket out of a tube.
Thanks again

 

[buckers]

Fixed.

This is the old gasket. Not hard to spot the breach....



Got some reinforced rubber type material from my mates company and cut a new one.

Straight away the pressure was soaring up...

 

[rtbcomp]

Fixing that shouldn't stop the air feeding back through the unloading valve though if the NRV is faulty.

 

[buckers]

Fixing that shouldn't stop the air feeding back through the unloading valve though if the NRV is faulty.

Which "fix" are you referring to? The second set of photos are for the Marksman compressor that wouldn't get up to pressure, and I think the fault is the leaky gasket. Correct me if I'm wrong, but it does seem to work now.

The first set of photos (Ranger compressor), showing the NRV turned out to be carbon deposits on the seat of the valve, not allowing it to shut when the motor turns off, and thus dumping the air.

Or am I missing something here.........

 

[rtbcomp]

....

Or am I missing something here.........

Yes - you're missing telling us which machine you're working on!

 

[buckers]

Yes - you're missing telling us which machine you're working on!

Sorry, it's me trying to be clever and imitate a woman, by doing 2 things at once.....

The NRV and carbon deposit problem is/was on the Ranger comp

The leaking gasket is/was on the Marksman comp.

Sorry if I confused you