Atlas Copco Compressor problem – please help guys

[Manchecd]

Hi guys

Still waiting to get a new hose which hopefully will be arriving tomorrow - not available "off the shelf" when you have an old compressor!

Thanks, Tigler, for the suggestion for re-using the old hose and maybe a jubilee clip would be fine but I had ordered a new hose before reading your comments.

Hope to be up and running soon!!

Colin

 

[Manchecd]

Hi guys

Finally got the hose yesterday, only to discover that the banjo was slightly smaller than the old one!! Although the thread part of the banjo bolt would go through it, the section above which goes up to the bolt head and which has holes in it for the air to pass through is slightly tapered out and would not go through. Aaaagh.

Fortunately, I have a lathe and was able to turn the taper down so that it would pass through.

I have now had a chance to try the new NRV and new hose on the compressor. Fingers crossed, it has all connected up OK, the NRV seems to work fine and there is no back leak of air. The pump now turns over easily when you switch off and then switch on again.

I have not had a chance to run it up to full pressure yet and will do so over the weekend. I have put about 50 psi into the tank just to test it and to check for leaks.

The only slightly unusual thing is that when I switch off, instead of getting a big hiss of air for a few seconds as the unloader valve kicks in, I get a slow hiss which lasts for a minute or two before all the air discharges. Any thoughts on this?

If I cannot cure this, I do not think it will be a problem. Once the pressure switch shuts the motor off (at 120 psi) all of the air will have discharged well before the pump starts operating again as this does not happen until the pressure has fallen to 80 psi.

So, I am hopeful that the new NRV valve will have sorted the problem. I have posted up a couple of photos so that you can see the new pipework arrangements.

The first section to the right of the old NRV, the silver pipe with the horizontal line on it, is there simply to ensure that the gold/brass NRV connection makes a good seal. When the new NRV was screwed straight into the old NRV, the big brass nut caught on the old NRV casing and prevented the new NRV tightening up properly. The silver pipe is essentially just a spacer piece.

The silver elbow then connects the new NRV output to the new hose and the banjo end of the hose screws into the tank as previously.

I would just like to say a big thanks to everyone who has contributed to this thread and helped me along the way. I feel very fortunate to have found such a great forum and to have had the benefit of all your advice and help.

I have learned a lot about compressors in the process!!

Hopefully the good old Atlas will run faithfully and without complaint for another 25 years now!!

Thanks again.

All the best

Colin

 

[tigler]

It may be that as it hasn't been run upto full pressure yet the NRV isn't fully seated.

 

[rtbcomp]

In the first picture on post #1 is that long silver cylinder at top of the compressor filled with compressed air? If so there could be a lot more air to discharge than the usual pipe-full, hence the longer hiss.

 

[Manchecd]

Hi guys

Thanks for these observations.

I will see what happens when it is run up to full pressure tomorrow and, yes, I think the long silver cylinder will be filled with compressed air, as the air from the two pistons comes through here and then down the finned copper pipr to the old and new NRV valves.

I will let you know what happens when I have run it up to full pressure tomorrow.

Cheers

Colin

 

[Manchecd]

Hi guys

I have run it up to full pressure now and it seems to work as previously but with a stronger blast of air when it switches off.

It still takes or minute or two for the air to stop discharging and I guess this may reflect the amount of air that needs to be discharged - there must be a fair bit in the long silver cylinder that needs to disperse.

So far so good, so fingers crossed it will be OK now.

Thanks again for all your help and support.

Colin

 

[rickyn]

Could you please post a link or advise where you brought your Nrv from. Your alternative setup is very simaler to what i would want to achieve