right i keep having problems with a leaking non return valve on my clarke shhhh compressor. i can clean out the non return valve the machine then runs good for like 5mins and then i can hear it blowing air back out through the compressor casings. if i slacken the pipe that comes out the compressor you get the air venting, so its deffinately coming back past the non return valve. i have replaced the non return valve in the past for a clarke spare and it didnt really make it any better. if you suck and blow through the valve after cleaning it, it doesnt inspire me with conifdence as sometimes it seals and sometimes it doesnt. can anyone suggest how i can replace what is there with something more reliable?? pics attached. the only issue i see is that there is a pipe t'eed off the non return valve that would need to sorted as all the NRV i can find are just an in/out.
- Thread starter Emmsy
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hermetic
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- 482
Hi Emmsy,
what type of valve is it?, is it a ball bearing and spring which seats into brass, or is it a turned plunger with a seal on it? if it is a ball that seats on brass, fit a new ball and give it a smart tap into the seat with a flat ended punch. If it is a plunger type you will need to look carefully at the seal to see which part is leaking back. I have fixed these by fitting better quality O rings, and also by putting a rubber disc under the plunger/ball to make up for a badly worn seat. Do you know the purpose of the tee off pipe? Is it to do with "unloading" the compressor when the motor starts? if so. is that actually causing the problem because it is not closing the non return valve when the compressor is up to speed? Hope this helps!
get back to me if the problem continues.
Phil/Hermetic
what type of valve is it?, is it a ball bearing and spring which seats into brass, or is it a turned plunger with a seal on it? if it is a ball that seats on brass, fit a new ball and give it a smart tap into the seat with a flat ended punch. If it is a plunger type you will need to look carefully at the seal to see which part is leaking back. I have fixed these by fitting better quality O rings, and also by putting a rubber disc under the plunger/ball to make up for a badly worn seat. Do you know the purpose of the tee off pipe? Is it to do with "unloading" the compressor when the motor starts? if so. is that actually causing the problem because it is not closing the non return valve when the compressor is up to speed? Hope this helps!
get back to me if the problem continues.
Phil/Hermetic
Hi Phil
the non return valve does come apart, and its just a top hat made of rubber.
im not quite sure what the t piece does, i need to get the cover off the control box thingy and see if i can fathom it out.
i did wonder about taking the rubber out the non return valve and then adding another non return valve in line.
the non return valve does come apart, and its just a top hat made of rubber.
im not quite sure what the t piece does, i need to get the cover off the control box thingy and see if i can fathom it out.
i did wonder about taking the rubber out the non return valve and then adding another non return valve in line.
right here are some pics of the non return valve and the pressure switch pipework.
looking at the pics in this album http://www.mig-welding.co.uk/forum/album.php?albumid=900
it looks like the t-eed pipe is a pipe to an unloading valve like you say.
the non retun valve doesnt have any spring inside just that rubber top hat.
if i suck and blow on it, sometimes it seals and sometimes it doesnt.
when i generally have to take it apart there is black bits in there, which i guess is bits of the oring, but could be something else.
this compressor was second hand about 3 years ago and its barely been used since, the non return valve was sticking back then so was changed. the oil looks grim so i was going to change this as soon as i get the NRV sorted.
looking at the pics in this album http://www.mig-welding.co.uk/forum/album.php?albumid=900
it looks like the t-eed pipe is a pipe to an unloading valve like you say.
the non retun valve doesnt have any spring inside just that rubber top hat.
if i suck and blow on it, sometimes it seals and sometimes it doesnt.
when i generally have to take it apart there is black bits in there, which i guess is bits of the oring, but could be something else.
this compressor was second hand about 3 years ago and its barely been used since, the non return valve was sticking back then so was changed. the oil looks grim so i was going to change this as soon as i get the NRV sorted.
pedrobedro
Man at Matalan
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I doubt if you'd seal that by sucking with your mouth, it works at 125psi. Is there an arrow on the valve body to indicate direction of flow?
hermetic
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Hi Emmsy,
that doesn't look right at all, is there a spring to hold the valve onto its seat? I feel there should be one that goes onto the smaller diameter of the "piston" and pushes it back towards the compressor, even if only lightly, as when pressure builds up in the tank it will help to seal it. try putting one in as I suggest and see if it works. it does not need to be particularly strong.
phil
that doesn't look right at all, is there a spring to hold the valve onto its seat? I feel there should be one that goes onto the smaller diameter of the "piston" and pushes it back towards the compressor, even if only lightly, as when pressure builds up in the tank it will help to seal it. try putting one in as I suggest and see if it works. it does not need to be particularly strong.
phil
hermetic
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or you could chuck the top hat and fit a spring and a ball bearing in its place. you should be able to seat the bearing into the brass with a sharp tap as I suggested above, or put an O ring in first then bearing and spring. the air from the compressor will push the ball off the seat to fill the tank, and the pressure in the tank will hold the bearing onto the seat when the tank is full. without a spring it will not work when the tank is empty!
the snooper
getting older by the day
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the t piece on that set up is for unloading the pressure in the air delivery pipe once it has reached pressure and switched off
the snooper
getting older by the day
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Barleysideboy
New Member
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Shhh 2/9 - NRV
I have a Clarke Shhh 2/9 air compressor with the same NRV & the same problem. How did you eventually fix your problem. Have been looking for a spare parts list on the web - no luck. Might just have to contact Clarke on Monday.
Cheers in advance.
I have a Clarke Shhh 2/9 air compressor with the same NRV & the same problem. How did you eventually fix your problem. Have been looking for a spare parts list on the web - no luck. Might just have to contact Clarke on Monday.
Cheers in advance.
brightspark
Member
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worth a look if the rubber top hat is leaking air the flat top might have a circular indent in it rub the face up flat on some emery cloth
till its flat and refit
i did it with mine and it works a treatBarleysideboy
New Member
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Nrv
Thanks for the quick response, I'll give it a try. Cheers
Thanks for the quick response, I'll give it a try. Cheers
octo0072000
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as for a spring try a retractable ball point pen should do it 
If you do put a ball bearing in there and seat it with a tap from a flat drift as suggested above, discard the ball that you used after seating and replace with an identical one, as the one you thumped will have a small flat on it. This was always the way we sorted oil pressure issues on early BSA motorbikes !!
brightspark
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ball bearings are just normaly used on the safety blow of valves .the non return are rubber or neoprene and much larger
