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  1. #1

    NEED HELP WITH A 3 TON AC SYSTEM MAGICAIRE HANDLER / LUXAIRE COMPRESSOR

    HELLO HOPE EVERYONE IS KEEPING BUSY WITH THE HOT WEATHER.

    2 days ago i changed a 3-ton r-22 condenser for a 2 family home the unit is for the 2nd floor apartment. The original condenser was dirty and the head pressure was too high, 300-315 psi tripping on high head. So i sold a new condenser. I installed a luxaire (guardian) 3-ton r-22 condensing unit. Vacuumed, test with nitrogen braze etc... Charged it by ambient 80+30 =110 f. Instead of weight because the manual and side of condenser did not list any amount. I charged the unit to 75 psi (45 f) suction low side 225 liquid high side. Super heat of 10-15 f .. I received a call the next day the conditioned space was not being cooled. The apartment was ranging from temps from 82-75 f with thermostat set at 69 f. I diagnosed the system, went into the attic seen that the evaporator is getting cold. The unit is draining condensate. The blower motor is working (squirrel cage). The indoor unit is a magic aire hydro air , air handler. The return only 1 central return is sucking up hot air of a temperature of 90 f. However the supply air coming out of the registers is a lazy 70 f. I know delta t is important and i also know that you need to be under 60 f to successfully cool. The air handler is a fixed orfice. However this machine has a hydro air hot water evaporator coil right before this machine provides air flow to the supply plenum. I noticed on top of the machine a can of nu brite that a lazy tech must have never thrown out. I tried to clean the coil to increase air flow with my own coil cleaner however the unit is still not cooling. The return filter was clean and i currently have the return filter out to try to increase air flow across my evap coil. I am not sure if the duct is insulated internally because i seen no insulation on the outside of the duct. There is no attic fan and very little insulation. I am really stuck on what to do. Any help would be appreciated. Should i remove the hydro air coil i believe it is causing a restriction but i am not positive. I even tried removing some refrigerant to make the coil colder but it did not help. Thank you
    Last edited by beenthere; 06-30-2012 at 06:35 AM. Reason: Got rid of all caps

  2. #2
    Join Date
    Mar 2007
    Location
    NW AR
    Posts
    2,478
    Wow. Guess I should quit cleaning condensers and just start selling them.

  3. #3
    Join Date
    May 2005
    Location
    South
    Posts
    580
    You might want to figure out why your evaporator is seeing 90 degrees when it's only 75 to 82 in the house.

    And why are you trying to clean the coil? is it dirty?

  4. #4
    Quote Originally Posted by truck12 View Post
    You might want to figure out why your evaporator is seeing 90 degrees when it's only 75 to 82 in the house.

    And why are you trying to clean the coil? is it dirty?
    it was 80-90 F fluctuating. The ac evap coil is clean however the hot water heating coil was quite dirty however i am only able to clean one side of the coil the side facing the air handler without removing the supply plenum and cleaning the other side. when i go back to the job tomorrow i will clean the other side

  5. #5
    Join Date
    May 2005
    Location
    South
    Posts
    580
    So did they need the new cond unit?
    It still doesn't cool.

  6. #6
    Join Date
    Mar 2007
    Location
    NW AR
    Posts
    2,478
    You said you diagnosed the unit. What was the final diagnosis?

  7. #7
    the old condenser was on its way out .. however there is still an additional problem. the air flow is restricted it is not blowing hard enough the fan speed is on highest setting. should i remove the hot water coil or bypass it with sheet metal duct with dampers for winter/summer modes. my final diagnosis is that im not cooling because i have a restriction in my supply plenum. i need to know the best way to try to clean a hot water hydroair coil

  8. #8
    Join Date
    Mar 2007
    Location
    NW AR
    Posts
    2,478
    No offense man but I see several technical terms jumbled in with a bunch of way-wrong techniques. I smell DIYer or just lacking in experience. Get your post count up and apply for pro membership then we can help you alot more.

  9. #9
    And did we bother to check for hot water flowing through this hot water coil yet? Or too busy trying to sell a condensing unit??? Not trying to be rude but....

  10. #10
    Join Date
    Dec 2010
    Location
    Virginia
    Posts
    355
    Make sure you take your temp split across the coil and not return and supply registers. I have seen quite a few attic systems that the duct was laying on the attic floor and picking up heat.
    I don't see how he could have hot h20 flowing through the hydronic heating coil unless they are using 2 different thermostats.

  11. #11
    Flow control valve stuck open on a domestic central heating system???

  12. #12
    Heck I don't know...haven't dealt much with hydronics. Seems like it be cause.

  13. #13
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    68,564
    With only a 20 degree delta, you aren't having a problem with low air flow.

    You charged a 13 SEER dry r22 unit to 30 degrees over outdoor ambient?
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

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