Push Pull Recovery

[Bash1803]

Hi Guys,

Just used the Push Pull method for the first time today recovering from a 160kg R134a circuit and I was pretty impressed with the initial speed.
However, a number of the more experienced members of my company don't rate this method of recovery and say it hasn't worked for them.

I am just interested to hear your stories/experiences of it, what went well/bad, limitations/where you can and can't use?

Any info would be great as I would like to build on a so far positive experience.

Thanks,

Bash

[RANGER1]

Bash,
Push/pull method works, no doubt about it.
You can also fill an empty bottle easily, reclaim bottle of course under a vacuum,
Best if system can run if possible to raise system discharge pressure,
hook up to the liquid source from liquid receiver or vessel, use hose or tube with no restriction & let it rip.
Hose & fittings with little or no restriction will fill bottle up before it gets a chance to equalize (hopefully), or chill it with a bit of ice to help.

[monkey spanners]

It works great to get most of the liquid out first, then swap hoses round to pull the vapour out.

Back when i did a lot of R12 to R134a conversions i used to start with push/pull but i would also have the bottle chilling when not being filled by pulling vapour out and dumping liquid back in (we had decent reco machine with proper sized condenser) You would get the bottle icy cold ready for the next system.

[Rob White]

.

It works well if the liquid is in one place and you can access it directly.

If it is a complicated VRF/VRV then the liquid might not be where
you want it or you might not be able to connect directly to the liquid side,
so not necessary that easy to do.

Rob

.

[sedgy]

hi all, yes the push pull method is very good, but I all ways had a reclaim bottle vaced out ready to use,= sedgy

[Glenn Moore]

Hi all
Slightly off the subject but important from a Health and Safety point of view. During my time as an apprentice at J&E Hall I built a refrigerant recovery unit using a small belt driven compressor to recover the gas from units if they couldn't be pumped down for some reason, while I was test running them
Anyway one of the Aquachill units had a faulty chiller, where the tube baffle plates had moved causing the tube bundle to rattle. So the bulk of the charge was pumped over into the condenser , and I asked one of the coppersmiths to unbraze the chiller so that I could fit a replacement, but told him to wait until I had run the recovery unit to get the last dregs of the R22 out of the system. Before I could connect the recovery unit I was called to meeting with the Foreman. I told the coppersmith to leave the unit until I got back as I didn't want him to unbraze the chiller barrel before all the gas had been removed.
When I arrived back from the meeting I found my coppersmith colleague unconscious on the floor with his torch still burning and the chiller liquid and suction pipes unbrazed.
What had happened was, as he heated the pipes the residue R22 gas was burnt by his brazing torch, which turned into Phosgene gas. Phosgene is a nerve gas and as he unbrazed the pipe work he breathed the Phosgene which affected the muscles around his heart which restricted his blood flow and caused him to pass out.
He spent the next week in hospital not allowed to move as any excessive movement he made could have caused his heart to fail. He recovered and returned to work , but it could have been fatal .Another lesson learned

[Grizzly]

AH!
The musky smell of Phosgene!
Not one I miss!
The taste was not to good either.
It's not the R22 anymore but put a torch near synthetic oil and see what happens!

It's been posted before but some may not of seen it?
http://www.youtube.com/watch?v=At2Ys9Eg-3s

Grizzly.