Replacing R502, low temp applications

[R12rules]

I am requesting info on what y'all did for replacing R502 in low temp applications.

Please list the refrigerant blend you switched over to, the oil you used and and issues you discovered in the process.

Thank you

[md master]

R-404a, R-408a. POE. Works well, never a retro, only new installation.

[selfemployed]

HP 80 and ABO. No problems yet.

[polartech]

For drop in's... HP80, sometimes HP81 for Ice machines. On larger stuff, I always do an oil change to POE and use either 404a or 507. I prefer 507 but most manufactures are using 404.

[jgjn]

Like selfemployed, HP 80 and ABO. No problems ,has been changed over for several years.

[icemeister]

I'll try not to repeat myself from my R12 retrofit reply, but here goes.....

DuPont's offerings for an "interim replacement service refrigerant" were basically HP80 (R402A) and HP81 (R402B). Whereas the HP81 was primarily for Manitowoc B-Series icemakers intending to achieve a higher discharge temperature for harvest than HP80, I'll just leave that one alone.

HP80 has been a very good refrigerant. It's application, like MP39 initially required a minimum 50% AB/MO mix, but that was dropped later on for all but those systems with oil return issues.

The only bad experience I've had with HP-80 is one where the system had a slow leak on the LP control bellows and the refrigerant fractionated to the point where when the system was topped off the head pressure went through the roof. Pulling the charge, evacuating and recharging with fresh juice and all was well again.

As I said in the R12 retro thread, it's now come time that we have to look at each system for HFC retrofit more so than the HCFCs like HP80, et al. Let's face it, there haven't been any R502 systems made in well over ten years, and even those are getting a bit long in the tooth.

[R12rules]

Originally posted by polartech
For drop in's... HP80, sometimes HP81 for Ice machines. On larger stuff, I always do an oil change to POE and use either 404a or 507. I prefer 507 but most manufactures are using 404.

Hey Polar, why do you prefer 507?

[polartech]

R12,
I don't know really. From what i understand 404a is a slightly better refrigerant. Compression ratios, I'm going to get trouble for that , are a little lower and the enthalpy (at -20) is a little higher. I don't know how the discharge temps relate, and I haven't taken both gases to the Pressure-Enthalpy diagram to know for sure. 507 was just what we started using here first. The other thing that's nice with 507... no glide.

[condenseddave]

404A, POE. Are you surprised????????????

[R12rules]

Originally posted by condenseddave
404A, POE. Are you surprised????????????

Nope

[freezingair]

[QUOTE]Originally posted by R12rules
I am requesting info on what y'all did for replacing R502 in low temp applications.

Please list the refrigerant blend you switched over to, the oil you used and and issues you discovered in the process.

Thank you [/QUOTE


Hi 404 is my best working methood

[freezingair]

[QUOTE]Originally posted by freezingair

Originally posted by R12rules
I am requesting info on what y'all did for replacing R502 in low temp applications.

Please list the refrigerant blend you switched over to, the oil you used and and issues you discovered in the process.

Thank you [/QUOTE


Hi 404 is my best working methood

in emerangcy cases 408 works wonder till -15

[R12rules]

Originally posted by freezingair

Hi 404 is my best working methood

in emerangcy cases 408 works wonder till -15 [/B]

Thanks.


genman ... is this helping you? got a good idea now on what the scoop is?


I can dig up some old threads argueing the finer points of this. Let me know.