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Thread: 407c retrofit

  1. #1
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    407c retrofit



    If a person was to retrofit a 2 ton heat pump from R22 to 407 C I understand there is a five to 10% capacity loss. Does this mean that the 407c charged would be 5 to 10% less than the R22 charge has indicated by the sticker on the unit?
    Also to compensate for this could a person install a larger evaporator say a two and a half two three times that would allow you to make up the difference and for the 407c to perform the same as R22?



  2. #2
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    Re: 407c retrofit

    The duty of the system is not determined purely by the evaporator. All of the components are selected to provide the required thermodynamic cooling duty. By mismatching the evaporator all sorts of operational problems could eventually become apparent.

    When the manufacturers upgraded from R22 to R407C, the systems were optimised to provide the original capacity.
    The oil in your R22 compressor and system may not be fully compatible with R407C, which could potentially cause long term oil return problems.
    Some of the drop-in blends may work fairly well in your R22 system, albeit with some fall off in duty.
    Mobile A/C at its best, see avatar.

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    Re: 407c retrofit

    Quote Originally Posted by hyperion View Post
    The duty of the system is not determined purely by the evaporator. All of the components are selected to provide the required thermodynamic cooling duty. By mismatching the evaporator all sorts of operational problems could eventually become apparent.

    When the manufacturers upgraded from R22 to R407C, the systems were optimised to provide the original capacity.
    The oil in your R22 compressor and system may not be fully compatible with R407C, which could potentially cause long term oil return problems.
    Some of the drop-in blends may work fairly well in your R22 system, albeit with some fall off in duty.
    I know that the mineral oil has to be replaced with poe. I did not think installing a slightly larger evaporator was a problem, as long as a txv was installed as well.
    I just thought a way to add more capacity was to slightly oversize the evaporator, thus making 407c perform more like r 22. My understanding is 407c has the closest pressures to r 22 anyway.

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