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Bikerdave
30-01-2017, 07:42 PM
Hi

I work for a small company that has some scrap chillers from vending machines that need refrigerant recovery. I passed F Gas a year ago and have since set up all required permits etc for me and for the company and now need to start recovering.

I have (I think) everything I need, a recovery unit, manifold and gauges, hoses, recovery cylinder and charging scales.

The chillers are small self contained units with around 3 or 4 oz (85 to 113g) of R134a per unit. No service ports but that's not a problem as once empty they will be scrapped, so I am using pliers that pierce the copper pipe.

I would like to chat with an experienced engineer just to guide me, as after the first unit I did today which I thought was empty but when I dumped it on the scrap pile it fell on its side and refrigerant came out! Clearly not empty. I don't need a training course just some wise words from an 'old hand'.

Thanks

Dave

Brian_UK
30-01-2017, 10:43 PM
Hi Dave and welcome to the forum.

Firstly, are you using two sets of access pliers or just one?

A little bit of techy which may explain your sudden refrigerant leak. This is a good time of year for the problem to occur as well.

Refrigerant will always migrate to the coldest part of the system which is generally the compressor when left outside and not running. The refrigerant will be mixed in with the oil contained in the compressor sump.

When you recover the refrigerant from the system it is highly unlikely that you will remove the oil logged refrigerant; it's purely physics so don't take it personal.

Now when you throw that unit onto the pile the energy is tranferred to the oil in the compressor which promptly causes the refrigerant to boil out of the oil and of course out of the access hole as well.

You can reduce the effect be heating the compressor can or perhaps beating it gently with a mallett while you are recovering the gas.

Bikerdave
31-01-2017, 09:57 AM
Hi Brain

Thank you for your time. (A UK forum and the guy that answers is around the corner, I am in Kingsteignton!)

What you say makes sense as the units have been sat around for years and in a cold damp shed. I think beating it gently will help the frustrations if nothing else. :)

I am using one set of pliers, they have a small bore of around 1 maybe 2 mm, connected to the low side of the manifold. I get about 1 bar when connected and the recovery pump reduces that to around -0.5 in a few seconds and if I leave it going for a few minutes it gets down to around -0.8 bar. There is no sign of any liquid in the sight glass and barely 10g of change on the scales, so I am left wondering if anything is actually being transferred.

Brian_UK
31-01-2017, 03:56 PM
To be honest the amount of gas to be removed could probably be contained within your manifold hose set and the recovery machine.

It sometimes seems a pointless exercise when looked at individually but when you add up all the single units that you are dealing with then it turns into a 'good thing' to do.