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  1. #14
    Join Date
    Mar 2007
    Location
    NW AR
    Posts
    2,478
    Always assume the condenser is dirty, even if it "looks" clean. Ive seen many "clean looking" condensers make alot of mud.

    375 looks about right for a 30 yr old unit with 110 deg OD and 95 deg indoor.

    Someone mentioned condensing temperature 40 above ambient not being right. Id have to disagree, its a 30yr old unit. Probably well under a 10 seer, which is the seer level that uses the 30 deg above ambient rule of thumb.

    37 deg SH is expected at 95 indoor ambient lol. Not out of line at all.

    Once you get your indoor ambient down, re-check your numbers.

  2. #15
    Join Date
    Jul 2006
    Location
    Virginia
    Posts
    4,619
    if the metering device is the correct size and the condenser coil is clean let it run and cool the place down then check it again also it is probably a 13 seer rated coil you installed and is picking up a lot of heat

  3. #16
    Join Date
    Jan 2009
    Location
    St Peters, Mo
    Posts
    56
    I plan to do a follow up tomorrow under less extreme conditions. I think I will clean the condenser coil also. Having not worked in such extreme heat, the high head had me alarmed. I'll post updated numbers. Thanks for all the feedback.
    Call for Heat means get more firewood

  4. #17
    Join Date
    Mar 2005
    Location
    Suppy NC
    Posts
    4,513
    back in the day it was not uncomon to find a unit on a roof or in sun on a 100 degree day to run at 350 or so
    check it when it cools dow if it ever does

  5. #18
    Join Date
    Dec 2002
    Location
    Houston,Tx.
    Posts
    15,919
    Quote Originally Posted by tinknocker service tech View Post
    back in the day it was not uncommon to find a unit on a roof or in sun on a 100 degree day to run at 350 or so.
    Why do Fedders package units come to mind?
    __________________________________________________ _______________________
    “Experience is a hard teacher because she gives the test first, the lesson afterwards". - Vernon Law

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  6. #19
    Join Date
    Feb 2006
    Location
    FL
    Posts
    565
    this is off an old rheem, just showing you cause it is possible to run that head in such high conditions.

    I have only seen this on old rheems for liquid line pressure charging so dont use it to charge other types if its not on there.
    Attached Images Attached Images  

  7. #20
    Join Date
    Jan 2009
    Location
    St Peters, Mo
    Posts
    56
    Thanks Jville, my conditions were off that chart. We, thankfully, have more moderate temps coming so it will be easier to diagnos the health of the system. I think the extreme conditions were at play in this case, will follow up tomorrow.
    Call for Heat means get more firewood

  8. #21
    Join Date
    Jan 2009
    Location
    St Peters, Mo
    Posts
    56

    What a difference 25 deg ambient makes

    Revisited this system today to replace cooked run capacitors that were causing fan to run backwards and trip compressor out on overload. Changed some loose spade connectors and foam cleaned condenser while there. Much more tolerable conditions to work in, 74 deg! System had been off all weekend, so these are pulldown conditions measured:

    radb= 80.4
    rawb=67.8
    oat= 74
    slt = 61
    sat temp/pres=40/68
    llt = 76
    con sat temp/pres=92/180
    subcooling=16
    superheat=21
    cond discharge temp=98
    con delta t=24
    supply temp=56



    How do these numbers look? System seems to be operating good for an old dog on borrowed tim.
    Call for Heat means get more firewood

  9. #22
    Join Date
    Jul 2005
    Posts
    5,491
    Doesn't look too great from here. The evaporator deltaT is too high and SST is too low (likely due to low indoor air flow) and the condenser discharge air temp is higher than the condensing temp (likely the result of a restriction upstream of the LL service valve. IOW the actual SCT is higher than the measured SCT).

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