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Electrocoolman
16-10-2010, 05:35 PM
Hi all....especially the oldies who might have an answer!

Just been to a local butchers to look at one of his coldrooms. Gauge (LP) pressure with system off did not tally with what I was expecting (R12 ?) .....pressure was too high.
A quick butchers (no pun intended!) at the TEV showed it was on Methyl Chloride.
This is my first run in with the gas, but I do know that it is one to be wary of...toxicity and flammable......turns out the system has been in since shop was built in the '60s. The old fridgidare condensing unit is still working sweet

Symptoms at first glance were possible shortage of gas, but sight glass was clear, so a quick pump down showed charge was probably OK and pointed to the TEV.

Adjusting the superheat has temporarily got the system cooling again, but now to the question of what to do next.

Are any of the currently available TEV's liable to work satisfactorily with the R40? (R12 for example).

What oil is likely to be in the system?.....Mineral?

Any suggestions for a drop in conversion? I haven't (as yet) found a P-T chart for R40 as my books don't go back that far, so direct comparison is currently difficult, but I guess that R12 might be close so possibly a R12 drop in would work.

Thanks, ECM

Andy
16-10-2010, 08:54 PM
Hi all....especially the oldies who might have an answer!

Just been to a local butchers to look at one of his coldrooms. Gauge (LP) pressure with system off did not tally with what I was expecting (R12 ?) .....pressure was too high.
A quick butchers (no pun intended!) at the TEV showed it was on Methyl Chloride.
This is my first run in with the gas, but I do know that it is one to be wary of...toxicity and flammable......turns out the system has been in since shop was built in the '60s. The old fridgidare condensing unit is still working sweet

Symptoms at first glance were possible shortage of gas, but sight glass was clear, so a quick pump down showed charge was probably OK and pointed to the TEV.

Adjusting the superheat has temporarily got the system cooling again, but now to the question of what to do next.

Are any of the currently available TEV's liable to work satisfactorily with the R40? (R12 for example).

What oil is likely to be in the system?.....Mineral?

Any suggestions for a drop in conversion? I haven't (as yet) found a P-T chart for R40 as my books don't go back that far, so direct comparison is currently difficult, but I guess that R12 might be close so possibly a R12 drop in would work.

Thanks, ECM

Helllo Electrocoolman:)

R12 would often be charged into methyl chlorine systems, I would try an R12 valve. I have seen bottles of methyl chlorine in BOC a few years back, so your system should still be viable. Mineral oil, 4GS from memory.

Kind Regards Andy D

alan wolf
19-10-2010, 07:05 PM
Hello

I can remember working back in the 60s on Methyl Chloride and SO2 systems but cant remember retrofitting.

Can remember that it can get very dangerous somehow if system is retrofitted and it is not perfectly clean.

I would make more enquiries on this 1.

There was a definite risk retro fitting these gases.

Aww

Electrocoolman
19-10-2010, 07:57 PM
Thanks Andy and Alan,

Although I've not tried to get hold of any Andy, you might be correct in thinking that its still available. Not sure whether its covered under Montreal Protocol as it doen't contain Fluorine. Does anyone know anything further regarding this point?

Thats a good point Alan regarding retrofitting. I'll have to do more research.

Quality
19-10-2010, 08:02 PM
I know its very potent stuff to your respirator system and that its heavier than air

please tread carefully