Can it be saved. Barely used compressor

[Tombodge]

So ive got a wolf compressor. 3hp. 100l. 14 cfm

Brought it about 4/5 years ago. Used it once or twice... It didnt work properly.

From memory it would fire up. Reach full pressure. But then refuse to kick back in again untill it was totally empty. I remember having to drain all the air out. Maybe leave it for a while. Then after pushing the button in and out it would kick in again.

I messed around with some stuff. Stripped and rebuilt some things next to the air regs/ buttons. Gave up with it. Left home.... and abandoned it at my parents house..

Now i need a compressor..

Shall i just buy a new one. Clarkie sell one simular for about £300.

Or is there a hand full of stuff i could buy and bolt on that would get it working and save me a few hundred pound.

Im thinking keep the tank. Compressor and motor and change everything else.. its fairly old now so i dont think parts will be around. Plus it was the cheapest you could get at the time. But maybe other parts will fit easily.


What should i / would you do? Just buy a new one and maybe piggy back the old tank to a 50/100l 3hp new compressor so ive got a 150/ 200l compressor. Or try and fix it.

 

[Dcal]

It's an easy fix
Just adjust or if that doesn't work, change the pressure control switch, (the black box with the red button)
They are cheap on eBay etc.

 

[gaz1]

id have bought . a new switch

 

[Al Strachan]

Ignore!

 

[rtbcomp]

Do you get a short hissing sound when the pump switches off at full pressure?

If not then the unloader valve on the pressure switch isn't opening, the thin pipe from the non-return valve (NRV) where the pump connects to the tank is blocked, or the NRV itself is faulty.

 

[WorkshopChris]

Possible start capacitor might be worth a look.

 

[AdrianH]

It could also be the starter cap is faulty and not giving enough umph to start it under pressure. But maybe worth checking the switch contacts first. Good squirt with switch cleaner?

Dam to slow!

 

[Tombodge]

For some reason i can remember the last conclusion i came to was the start capacitor but that was years ago and a compleate guess I think because it was trying to but failing to spark up.

I did try adjusting the pressure control switch but it didnt do anything. Which is when i stripped it all down. Not that i new what i was doing or looking for lol

So if i buy a new switch... start capacitor and a NRV and pipe it should be fixed?

How do i know the spec of all of these things to buy. or are they all the same kinda spec and interchangeable?

Sounds like its worth spending alittle time trying to get it sorted.

Thanks for all your help

 

[Tombodge]

Do you get a short hissing sound when the pump switches off at full pressure?

If not then the unloader valve on the pressure switch isn't opening, the thin pipe from the non-return valve (NRV) where the pump connects to the tank is blocked, or the NRV itself is faulty.

To be honest i cant remember. I can remember the first time using it thinking this just doesnt seem quite right so perhaps the missing hiss was one of them. Followed buy the rest of the problems.

How do i know what kind of NRV to replace it with. Ill strip down and check the pipe to make sure its not blocked

 

[Tombodge]

Is this the pipe i need to check is unblocked? Seems like a good free place to start

 

[Dcal]

Don't be in such a rush to buy bits before you know what's wrong.
Can you get it back to the condition it was in befor? (I.e. Running but not switching back on)
What pressure does it make after it runs the first time? (the reading on the tank pressure gauge)
After it makes that pressure does it switch off ( and do you hear a hissing sound as the unloaded valve does it job and releases the pressure in the pump cylinder head)
If you release the pressure does it try to start again?
If so at what pressure?
Does it manage to start or does the motor hum but not turn?

I'm not convinced it's the start cap as if that was faulty it would try to start and ether fail to start and hum before either tripping out or blowing the fuse in the plug or the mcb on your consumer unit.
You have said you tried to adjust the pressure switch. Did you adjust it the wrong way?
There are two adjustments on them one for cut out pressure (max pressure the compressed will put out, usually 10 to 15 bar) and the cut in pressure (usually 1 or 2 bar below the max pressure, so say 8 to 13bar)

Sorry if I'm making this sound complicated (it's really not) but if you don't try and get a logical fault finding process you could be just wasting your money.
Having said that unless the motor or the pump are scrap it's worth fixing

 

[rtbcomp]

The cheaper compressors usually only have one adjustment, ie cut-off pressure, the cut-in pressure is fixed a couple of bar lower.

Is this the pipe i need to check is unblocked? Seems like a good free place to startView attachment 158100View attachment 158100

That looks like it, it will be about 1/4 inch diameter and connects to the pressure switch.

If you disconnect it at the switch and start the compressor you should get a healthy blast of air from the free end.

 

[Dcal]

The cheaper compressors usually only have one adjustment, ie cut-off pressure, the cut-in pressure is fixed a couple of bar lower.

I agree, but there are ways of adjusting them. (not that I'm suggesting Tombodge does) but if he doesn't get it running there is no way of ever knowing what's wrong with it.

 

[rtbcomp]

^^ LOL - if he can't find out what's wrong he can't get it running

 

[Morrisman]

I had a similar problem, turned out to be some sort of mechanical device in the end of the electric motor had burnt out, a two-stage starter device. It would try to start, then stop, then try again etc. A new motor could have sorted it, but I never got round to it.

I scrapped the compressor pump, as I was in the Philippines and couldn’t find a suitable motor, or repairman, but I still have the big pressure vessel in my garage loft, dragged it back to the UK when we moved.

One day I’m gonna fix it up.....

 

[Morrisman]

Is this the pipe i need to check is unblocked? Seems like a good free place to startView attachment 158100View attachment 158100

It won’t be blocked, but there is a small valve device in the end, to relieve pressure on the compressor pump when starting. Make sure it is not leaking back, and is not jammed. There should be an O ring type seal in there.

 

[Tombodge]

Ill have a play with stuff. My problem is im kinda in a rush to use it. At the moment it doesnt start atall but i might have unwired the caps last time i messed with it.

Thanks for all the help.

Is the buy a 3 hp 50l compressor and piggy back it to the 100l tank a good idea if it comes to it. Seems to make sence to me but might lower the flow or pressure rating or somthing

 

[Al Strachan]

if its purely the unloader valve, or pipework to it, you should hear the motor trying to start. check you've got voltage to the motor when trying to start it. If its been left unnatended previously with a duff unloader, theres a high chance that the motor is damaged with it being stalled and energised.

 

[rtbcomp]

It won’t be blocked, but there is a small valve device in the end, to relieve pressure on the compressor pump when starting. Make sure it is not leaking back, and is not jammed. There should be an O ring type seal in there.

My experience says different. My brand-new Clarke compressor wouldn't start under pressure and I found a bit muck in the unloader pipe.

If the unloader valve is leaking you'll feel the air coming from under the switch, it could be jammed closed I suppose. The actuator (bit of plastic) inside the switch could be broken or the valve could have moved so the actuator doesn't reach it.

 

[Tombodge]

I cant even get it to start to check all these things. I might just buy the bits mentioned to see if it will work