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  • S Ebels
    S Ebels Member Posts: 2,322
    Got a question

    I've just fired up a new A/C system (hypothetical) and the indoor temp is at about 78-80*. I adjust the charge to manufacturer's guideline of 8* subcooling (TXV system) with the room at the above mentioned temp. What's the effect of the high room temp on my subcooling reading? Do I want to leave it a tad shy, over or dial it right on regardless of the indoor load?
  • Eugene Silberstein
    Eugene Silberstein Member Posts: 1,380
    Use your 8 degrees

    You are right on point with your 8 degrees, which is what the manufacturer asked for.

    As the space temperature changes, the operating pressure on the low pressure side of the system will fluctuate, but the evaporator superheat will remain constant, thanks to the TXV. Refrigerant will back up in the receiver (which may be the bottom of the condenser, depending on system layout) when not needed but will not affect (noticeably, anyway) the subcooling as calaculated at the outlet of the condenser coil.

    Your charge is right just the wa it is.

    Sorry for the delay in getting back to you.
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