Refrigerate recovery

[maciceman]

Hearing more and more of engineers using a recovering method by using the system compressors to pump directly into the recovery bottle.
VRV system which has two or more compressors and one requires changing or requires pressure/leak testing and using the running compressor to pump into the recovery bottle.

Iv some safety concerns that by boing so there's no Head pressure control for the bottle if theres a possibility of over changing.
plus what's the potential for oil loss with the working compressor moving oil straight into the bottle,with no oil sight glass on most VRV compressors.
Is this good practice?

plus how many of you would close the service ports/ pipe lines on a VRV and just recovery what's in the condensor to fit a new compressor. My thoughts are the compressor has failed for a reason and it's a good time to confirm the gas charge.

[Brian_UK]

If you don't recover the whole refrigerant charge then how will you know how much to put back into the system after the repairs?

You should always be monitoring the recovery cylinder weight so an overcharge should not happen.

Using the push/pull method of recovery also speeds things up somewhat.

[r.bartlett]

VRV's

we would often just recover across from the condenser to the pipework by shutting the service ports. that way the whole charge doesn't need to be pulled and the amount of refrigerant moved is greatly reduced and the work gets done far quicker. You can carry on removing and PLT the condenser without worry. . Vacuum out and open the valves. Job done

[Steve186]

As brian said push/pull is how to recover its quick and easy ive got a 1/2" bottle fitting with a sight glass run the system once the liquid stops shut the system down and recover the remaining vapour i can recover 900 kgs in 4 hours uaing this method
Never rely on shut off valves holding up may be quicker
But its not safe pratice and what can go wrong will go wrong to many cowboys out there cutting corners to win work