Can't do better than 13*TD??
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  1. #1
    Join Date
    Jun 2008
    Posts
    13

    Confused Can't do better than 13*TD??

    Hey guys, Trying to determine whether or not I have a faulty compressor. Possiblly bad valves??

    I have a 2.5 ton York condensing unit model (030) and matching indoor coil, 12 years old (estimated). R-22; metering device is an orfice. I think #63 (don't quote me) 25ft line set length at most from furance to outdoor unit

    Ambient 95 degrees...

    I have an 82 lb suction; 200 lb head; 59 degree suction line at compressor about (-3 superheat) and 98 liquid line about (-3 subcooling).

    Compressor RLA= 13.8 Currently running at 10.3

    I am only getting a 13 degree temp difference. (supply air-56) (return air -69)

    I noticed that the liquid line is rather small. I think it is a 1/4 instead of 3/8tubing. Does this play a role in these readings?

    Can't do any better than the 13 degree TD????

    Thoughts.....

    Comments/questions welcomed and encouraged

    Thanks
    E

  2. #2
    Join Date
    Aug 2007
    Location
    MN
    Posts
    2,677
    probably overcharged with a blanket on the evaporator, if your not a tech call one.
    You can't fix stupid

  3. #3
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,597
    More like 10° SH, and 3° SC.

    Not a compressor valve problem.

    Unfortunately, we're not allowed to give technical advise in the open resi forum. Protects DIYers, from themselves.

    If your a tech, get your post count up to 15, and apply for pro memnership.
    Then you can ask technical questions in the pro forum.
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  4. #4
    Join Date
    Jan 2008
    Location
    BAYOU LAND
    Posts
    697
    Quote Originally Posted by coors66 View Post
    Hey guys, Trying to determine whether or not I have a faulty compressor. Possiblly bad valves??

    I have a 2.5 ton York condensing unit model (030) and matching indoor coil, 12 years old (estimated). R-22; metering device is an orfice. I think #63 (don't quote me) 25ft line set length at most from furance to outdoor unit

    Ambient 95 degrees...

    I have an 82 lb suction; 200 lb head; 59 degree suction line at compressor about (-3 superheat) and 98 liquid line about (-3 subcooling).

    Compressor RLA= 13.8 Currently running at 10.3

    I am only getting a 13 degree temp difference. (supply air-56) (return air -69)

    I noticed that the liquid line is rather small. I think it is a 1/4 instead of 3/8tubing. Does this play a role in these readings?

    Can't do any better than the 13 degree TD????

    Thoughts.....

    Comments/questions welcomed and encouraged

    Thanks
    E
    do u do this for a living? if so get your post count up to 15 and apply for pro then we can talk about it.this is an open forum,too many diy er's
    The government works for me. I do not answer to them, they answer to me.

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  5. #5
    Join Date
    Jun 2008
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    13
    Quote Originally Posted by beenthere View Post
    More like 10° SH, and 3° SC.

    Not a compressor valve problem.

    Unfortunately, we're not allowed to give technical advise in the open resi forum. Protects DIYers, from themselves.

    If your a tech, get your post count up to 15, and apply for pro memnership.
    Then you can ask technical questions in the pro forum.
    Gothcha! Didn't know. Thanks guys.

    cmajerus: Blanket on the evap??? I would have low suction and and a frozen coil.

  6. #6
    Join Date
    Aug 2007
    Location
    MN
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    2,677
    Quote Originally Posted by coors66 View Post
    Gothcha! Didn't know. Thanks guys.

    cmajerus: Blanket on the evap??? I would have low suction and and a frozen coil.
    I'm blind today from welding burn of the eyes but with your -3 superheat I slapped out a quick response, of course you get some weird readings with 10 lbs extra r22 in a system, but would likely have a bit higher head pressure
    You can't fix stupid

  7. #7
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,225
    Quote Originally Posted by coors66 View Post
    Hey guys, Trying to determine whether or not I have a faulty compressor.

    Possiblly bad valves??

    I have a 2.5 ton York condensing unit model (030) and matching indoor coil, 12 years old (estimated). R-22; metering device is an orfice.

    Ambient 95 degrees...

    I have an 82 lb suction; 200 lb head; 59 degree suction line at compressor about (-3 superheat) and 98 liquid line about (-3 subcooling).

    Compressor RLA= 13.8 Currently running at 10.3

    I am only getting a 13 degree temp difference. (supply air-56) (return air -69) Can't do any better than the 13 degree TD????
    Increase the return air to at least 76'F !

    What is the AHU air flow?
    Designer Dan
    It's Not Rocket Science, But It is SCIENCE with "Some Art". ___ ___ K EEP I T S IMPLE & S INCERE

    Define the Building Envelope and Perform a Detailed Load Calc: It's ALL About Windows and Make-up Air Requirements. Know Your Equipment Capabilities

  8. #8
    Join Date
    May 2004
    Posts
    1,462
    Not commenting on the SH, SC, or pressures but there may be nothing wrong with a 13 deg drop. In fact that may be great! Your temp drop will depend on how much of your cooling capacity is going to latent cooling. In other words if the humidity in the space is high more of your total cooling will go to latent and less to sensible and therefore a lower temp drop. It is impossible to determine if a sytem is working properly on temp drop alone.
    If all else fails....Try reading the directions!

    Tell it like it is and let the chips fall where they may.

    Any views or opinions stated here are strictly my own.


  9. #9
    Join Date
    Jun 2008
    Posts
    13
    If anyone else has the same symptons as me, it's the comp. The valves were bad. Pumped it down and whatda ya know, it didnt hold. Replaced the comp. and 19 TD 65 lb suction 225 head. Beautiful!

    Thanks for all the help...well, sort of! This forums is a waste. You cant even answer a simple question on here w/o becoming a member!

  10. #10
    Join Date
    Dec 2002
    Location
    Houston,Tx.
    Posts
    15,778
    Quote Originally Posted by coors66 View Post
    Compressor RLA= 13.8 Currently running at 10.3

    I am only getting a 13 degree temp difference. (supply air-56) (return air -69)

    Thanks
    E
    That RLA could be "rated load amps" and were exactly did you take the TD hopefully
    not at the return and the supply grilles.
    Also the WB would really be nice to know.
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