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Hi,im busy with a old R502 chest freezer,if found that the replaced compressor from R502 was R12, the owner sed it was working well till it died, so i replaced the R12 com to a new 1/3 hp R134.The problem is now that it only freez the back wall of the freezer,if i add more gas it starts to freez to the comp, but not inside. I deside to Replace the R134 with a 1/2 hp R22 comp.Wil it do the job?
Thanks
No. You need to go back to R134A and you need to calculate new capillary tube for R134A using ,for example, DanCap software:
http://tinyurl.com/2hlyom
Or, you need to change TEV if it is that the case there.
Thanks nike123, your always good help.
Changing refrigerants and compressors in a system should be based on the original compressors (that performed properly) capacity at a given SST. The task is to match btuh capacity, not HP.
You went from R502 to R12 to R134a, on a low temp system R134a can be weak as it drops below a 0F SST. Do you have the original R12 compressor model number and your existing R134a model number?
If your existing R134a compressor matches the capacity then apply what nike123 has suggested.
powell
If you ask me, I would change refrigerant to R404A. That way, you have matching heat exchangers and you achieving original capacity of unit. Then you need to find compressor for R404A for that original capacity and change capillary tube to match the R404A and compressor capacity. Also, change filter-dryer to match oil and refrigerant.
Check also that POE oil is in system and compressor or flush system. Max allowable amount of residual mineral oil is 5%.
Charge to 75% of original charge for R502 and start system. Then gradually add 5% charge and check superheat and subcooling constantly. Total charge is around 85% of original R502 charge.
Then you should put some stickers which states amount and type of refrigerant and oil.
That should bring back that freezer in good working order again.
Something to remember aswell is the phasing out of R22. By 2010, all new production of R22 will stop and only reclaimed R22 will be acceptable to use. By 2015, all R22 will be banned for use.