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super heat & sub cooling right?

Tim Potter
Tim Potter Member Posts: 273
in A-C, Heat Pumps & Refrigeration
My daughter is buying a house in Denver, The inspection turned up a couple of HVAC items, so the seller had the system inspected. R-22 system with 75* ambiant the Sub Cooling was 19* and super Heat was 17*. Ther also reported dt 24* at the coil. Does that sound right to you guys?

Thank You,

Tim
Winter Park, CO & Arvada, CO

Comments

  • Ironman
    Ironman Member Posts: 7,556
    We would actually need all the numbers including indoor dry and wet bulb temps, but a 24* delta through the coil is too much and indicates low air flow. The sub cooling is also too much, but the airflow issue should be addressed first.

    Is there a TXV or piston metering the refrigerant?
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
    GBartaircooled81
  • pecmsg
    pecmsg Member Posts: 5,301
    Who did the inspection, home inspector or HVAC Contractor.

    Agreed more information is needed.
  • Tim Potter
    Tim Potter Member Posts: 273
    Thanks Bob, ill get that info. @Ironman

    Home inspector flagged it, local HVAC contractor hired by seller did the inspection. @pecmsg
    Winter Park, CO & Arvada, CO
  • pecmsg
    pecmsg Member Posts: 5,301
    Hire your own HVAC contractor
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 16,507
    Depends on the equipment normal or high efficiency. DT should be about 20, sub cooling 15-20 superheat 15-20 but depends on the metering device some systems will run lower superheat. You not to far out of wack could be as simple as a dirty air filter
  • unclejohn
    unclejohn Member Posts: 1,833
    the unit may have been in a dehumidify mode or low indoor temp. and the tev shutting down which would bump up the sub cool.
  • John Mills_5
    John Mills_5 Member Posts: 952
    Denver can be pretty dry which increases the TD. So if very low humidity, 24 may not be out of line. SH seems fine, SC says it could be a tad overcharged.
    aircooled81
  • GBart
    GBart Member Posts: 746
    Get the factory charging and running spec's, depending on what they specify it could be right, it could be wrong, their chart may ask for outdoor ambient, may ask for indoor wet bulb, who the hell knows ???

    let's all please stop with speculation and go to the source, the factory, please!!!
  • GBart
    GBart Member Posts: 746
    Let me give you an example, looking at a Goodman unit chart right now, if the air temp entering the condenser is 80F and the return air temp is 85F it says the superheat should be 26F

    if the air temp entering the condenser is 80F and the return air temp is 75F it says the superheat should be 12F

    and for every unit and every manufacturer these numbers will probably be different

    what catches my eye is the 24F drop at the coil

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