TEV for RS-24 (R-426A)?

[Electrocoolman]

Hi guys,
Have today been working on an old coldroom. Originally on R12 - as determined by standing system pressure - as usual nothing marked anywhere!
R12 recovered, Leak repaired (on condenser), New drier, Pressure tested OK, recharged with RS-24 (R12 drop-in) - so far so good.
System flooding back badly. TEV adjusted but still not regulating very well. Then found TEV was for R22.!

Q: Would you fit a R12 TEV (difficult to source), or would you use a R134a TEV seeing that RS24 is 93% R134a ?

Q: How else can you identify a refrigerant (apart from chemical analysis).?.....NB. System had been switched off for +24hrs with door wide open...Pressure was 72psig ambient temp +19C...(R22 at this temp shows 110psig)

All ideas welcome.

[nike123]

Hi guys,
Have today been working on an old coldroom. Originally on R12 - as determined by standing system pressure - as usual nothing marked anywhere!
R12 recovered, Leak repaired (on condenser), New drier, Pressure tested OK, recharged with RS-24 (R12 drop-in) - so far so good.
System flooding back badly. TEV adjusted but still not regulating very well. Then found TEV was for R22.!

Q: Would you fit a R12 TEV (difficult to source), or would you use a R134a TEV seeing that RS24 is 93% R134a ?

Q: How else can you identify a refrigerant (apart from chemical analysis).?.....NB. System had been switched off for +24hrs with door wide open...Pressure was 72psig ambient temp +19C...(R22 at this temp shows 110psig)

All ideas welcome.


If you have drop-in than you should use TEV for original refrigerant. Drop-in is designed to be replacement without need to touch anything on system.

But if you have R22 TEV is it possible that original plant is designed for R22 instead of R12 and you should change refrigerant with appropriate R22 drop-in.

[Electrocoolman]

Thanks Nike,
I've got it running with a R134a TEV at present, which appears to be working reasonably well.
I might try a R12 valve if I can source one if the result is unsatisfactory, but with the impending R22 phase out I was also trying to get away from R22 and blends using R22 etc.

Condensing unit is an R22/R502 unit (from compressor model) which is obviously 2nd hand, but why was it on R12 if everything else points to a R22 system?

Cowboys?