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Sunday thinking

On an AC evap coil ,what percentage of the coil is used for super heat ? TXV and orifice and cap tube systems! Just thinking!


  • TonyS
    TonyS Member Posts: 849
    My guess

    would be 10 to 15 percent. If you have an electronic sightglass ,you could remove some fins and get the probes clamped on and find out.
  • don_9
    don_9 Member Posts: 395

    I would think the load on the evaporator would dictate what percentage you would get.

    Lets take a orifice/piston system.On a mild day say 75 degree oat you would have some where around 20 to 25 degree superheat.now on a 95 degree day you could have six to 12 degree superheat.The reason being as the load changes so the temp and pressure.Higher temps are going to force more refrigerant thru the orifice dropping the superheat and on a milder day less so the superheat will be higher..

    As for the txv its going to try and maintain  a 6 to 12 degree superheat under all load condition.That why with a txv you charge by sub-cool but check superheat to see if your txv is doing it job.And on a orifice system you charge by superheat but check sub-cool so you know how much refrigerant is stacking in the condenser and if you are getting a column of liquid heading to the indoor coil.
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