502 replacement

[coldkeeper1]

Once I successfully finish with the troublesome Thermoking CB MAX, if I ever do, I´m suppose to repair an old SUPER II reefer unit. It used to work with 502. I know that 402A is the first choice for 502 system retrofit, but it is not readily available in my area. Are there any other possibilities with more commonly available refrigerants? Thank you.

[TDI]

r403b is the drop in replacment ref for 502 also called 69l

[powell]

R408A is very popular and works great.

[absolute-zero]

You could always convert the unit over to R-404a too.R-69L was used by TK, during the transition or also known as the CFC phase out period. If memory serves me correctly this was the possible desired replacement of R-502 until R-402a came along. The refrigerant R69L was not used long, as I think the awareness and safety of handling the refrigerant was at higher risk of equipment damage and personal safety, due to its flamabilty.

[smpsmp45]

Copeland has a good article on change over from R22 to R404A.

USe R 404A itself.

[old gas bottle]

just dont forget to flush and change the oil to a synthetic type,you will also need to ajust the superheat or change the expansion valve also,thats another reason why drop- ins are more popular.

[absolute-zero]

just dont forget to flush and change the oil to a synthetic type,you will also need to ajust the superheat or change the expansion valve also,thats another reason why drop- ins are more popular.

On transport units such as the Super II; there will be no need to mess around with adjusting the TXV when replacing R-502 with R-404a. As far as oil goes The Super II is equiped with either 426 or 430 reciprocating compressor therefore, TK POE oil part number 203-513 (if qts lt= x) x(4)= 4 is the oil amount that should be used. I may suggest installing a compressor oil filter kit if unit is not already equipped with one. Also replace the drier and run unit for several hours in heat mode and change the compressor oil along with oil filter again.This should be a good flush of the system to ensure all old oil is out. Finally run unit and cycle all modes of operation to ensure all is ok.PS: sorry for the bumbling retarded pargraphs and run on sentences.Regards A-Z

[paulo almeida]

Once I successfully finish with the troublesome Thermoking CB MAX, if I ever do, I´m suppose to repair an old SUPER II reefer unit. It used to work with 502. I know that 402A is the first choice for 502 system retrofit, but it is not readily available in my area. Are there any other possibilities with more commonly available refrigerants? Thank you.

use :
ISOCEON MO79 (R-422A) of DUPON
Direct replacement, d'ont need change oil.

[SKOOBY]

You are better off the R404a route.
The trouble with drop ins you can have problems with oil migration etc.
Abbs is spot on the button for a long term fix

[absolute-zero]

You are better off the R404a route.
The trouble with drop ins you can have problems with oil migration etc.
Abbs is spot on the button for a long term fix

Skooby, Thanks for the backing support. I would assume all repairs were to be made as a final long term repair. Is this not always the case with some of the members here? I wouldnt think for a second that the members here would want to exhaust informative resources to have an outcome of a temporary rigged up system. just my opinion.