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Thread: Poor Cooling

  1. #14
    Join Date
    Feb 2005
    Posts
    66
    tecchris, i think you're on the right track. it looks like you have the wrong piston size.there's no way you would have 74# suction and be low on gas with a return air of 73 deg. the piston is too large, not allowing liquid to back up into condenser for subcooling.install a t.x.v. and charge by subcooling (6-8 deg.) then set your superheat.but, make sure the t.x.v. is not commercial,must be for residential with off cycle bleed port.or,find out the correct piston for the cond. unit.

  2. #15
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,048
    To heykiss.

    Alot of residentcial txv's are non bleed.

    Next why only bribg the sub cool to 6 or 8, and then adjust superheat?

    Where talking a/c not walk in freezer.
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  3. #16
    Join Date
    Feb 2005
    Posts
    66
    beenthere,6-8 deg. is my starting point,then set s.h.,then depending on seer (forgot to mention), i would add refrig. for 8-13 deg sub. because if it's only 85 deg. outdoor amb. i would worry about higher than normal head (causing higher amperage draw, killing eff.) when it got to 95 deg. amb. just my way of doing a piston to txv upgrade. thanks for the tip on resdential txv's not all having % of bleedport. i shouldn't rely too much on supplier info.

  4. #17
    Join Date
    Mar 2005
    Location
    Suppy NC
    Posts
    4,513
    i will be willing to bet this is an old fedders with cap tubes. the head seems a little low and super heat a little high should be between 12 and 15 degree superheat. your head may wind up arround 250. if my memmorie is correct about those old war dogs.

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