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View Full Version : Trane RTHB chiller refrigerant refrofit







tblacker
22-08-2013, 04:43 PM
I have five 150 ton Trane RTHB screw chillers currently producing 20 degree F. LWT. They are used for process cooling. All 5 chillers are currently using R-22 refrigerant. For years I have watched for and investigated suitable refrigerant replacements. None of the blends available at the time emulated the characteristics of R-22 at these lower temperatures. I have recently contacted DuPont and spoke to one of their refrigerant engineers about my concerns. The gentleman has been formulating refrigerants since 1970 and informed me that 407-a would be a suitable replacement. Oil replacement (P.O.E) and seals would be necessary. The problem is Trane does not and will not do the retrofit. Their response is that the units were only designed for R-22 and no other refrigerant will work. Has anyone done this change on their own? I could sure use some advice on this one.

camelCase
23-08-2013, 04:56 PM
I've seen trane and various other units switched from R-22 to 407-a. POE based lubes are a lot more expensive than what you're using probably using now - but they are well worth it. There are a lot of 12,000hr POE's out there too. Seal changes will also be necessary because of how the lubes interact with them. POEs tend to swell seals a bit, while your previous lubricant may have caused them to harden slightly (common with mineral oils). Swelling the hardened seals will cause them to fail. Swelling new seals will not cause them to fail - hence the need for replacement.

I'm not sure why Trane would say you can't do a retrofit. Maybe because they don't want to cover any liability for errors...?

knightlight
24-08-2013, 03:34 AM
One reason they want is that their engineering departments haven't approved the use of the 407 refrigerant family.
It wasn't until recently that any manufacturer approved of the use. The only ones I know of are Copeland (all R22 compressors) and Bristol (in select compressors) No equipment manufacturer has done so and since they haven't approved the use of the R407 family they will not retrofit their equipment. Also the use of the R407 refrigerants will void any warranty you may have on the equipment. If warranty is not an issue then R407c for medium temp/high and R407a for low and medium temp. applications are the very best option at this time. They are a closer match to R22 than anything on the market today. In fact it is so close that most new R22 TXV/TEV power heads have both refrigerants listed on them. There isn't a perfect R22 replacement but the R407 family is about a 98% orthere about

tblacker
25-08-2013, 01:40 AM
Thanks for the response. I have been servicing my own chillers for the last 30 years and really didn't expect Trane to coorperate.