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Will M099 work as a direct replacement if the condenser is above the evaporator coil ? I know 422 has a hard time not sure of the 407 .. has anyone ever tested the difference between the three? Any advice would help.. just don’t want to spend or charge for the 22 but heck they all jumped sky high lol thanks in advance 


  • pecmsg
    pecmsg Member Posts: 4,193
    edited August 2022
    This is really a question for the supply house.

    High temp, med temp or low temp?

    Mo99 and R-422(B) will operate fine without a change to POE oil but I add some anyway.

    R-407 A, B, or C ? Will require mostly POE oil