How can I safely depressurise A/C to replace condenser?

In message , Thomas Hood writes

I would imagine all the gas has gone by now anyway. When I replaced my condenser last year there was nothing there when I disconnected the pipes.

No, it's not legal - get a professional in.

you shouldn't. preferably get it emptied by a professional who will recover the refrigerant.

But if you insist, on a dry day, get everything ready and as much undone as possible first , then undo a union a little and allow the gas to slowly escape, that way it won't take a lot of oil out with it, when the hissing stops change the bit and reseal the system as quickly as possible, then get it vacuumed, leak checked and refilled.

Well regardless of the law, I wonder what the best option for the environment really is?

Having been round many of S.E. London's scrap yards over the years I have strong doubts they bother to contain these gasses on disassembly

--regardless of the regulation. Sure they'll probably have the kit to get whatever piece of paper Whitehall demands, but is it ever used?

For arguments sake, I think there are 3 scenarios: a) I vent the gas to the atmosphere and reuse the old condenser b) the scrap-yard vents the gas to the atmosphere, the condenser is melted down and I have to purchase a new condenser whose manufacture (aluminium smelting, brazing etc.) is further deleterious to the environment. c) the scrap-yard properly contains the gas, but the environmental impact of the new condenser manufacture is still arguably worse than releasing a bit of R134a (I've no idea if this is true, but gut feeling would suggest it is)

Should I have more faith in Steptoe &c.?

Tom

Any decent scrap place now has the kit and uses it. I now understand that you want to recover a good bit from a car before you scrap it? If so then just release the gas if your conscience will let you, it only has a relatively short life (8 years IIRC) before it has no damaging effects . (R12 is 100 years)

1kg of 134a has the same greenhouse gas effect as 1200kg of CO2 so it may be more enviro friendly to buy rather than release. 134a has no ozone depleting chlorine.

Mrcheerful

I'd imagine if they have the kit, they will use it and reclaim the gas.

Shoot it with a .177 air rifle? You'll be in little danger of it blowing out in your face as an ice cold liquid at least.

It is the phase change from liquid under to pressure to free gas that creates the ice cold freezing effect.

The message from Elder contains these words:

It still chills the liquid though. The faster moving more energetic molecules leave the surface, leaving the average energy (and thus the temperature) of the remaining molecules in the fluid lower.