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  1. #1
    Join Date
    Mar 2008
    Posts
    205

    Is there anything I can do about this?

    At my work (large high school) 2 conjoining rooms share a common A/C / furnace. The A/C is a 4T Trane (last of the R-22's and we got it on the cheap) and it was installed in April. The previous unit was a 4T Trane. These unit have supplied conditioned air to about 1800 ft2 between the 2 rooms.

    The AH was put in when the building was constructed in 1993. The blower and the inside of the AH is filthy. Still, it keeps on going. The problem is w/humidity. If you leave it set on 76-78* like the electricity usage Nazis command, the rooms stays as humid as a jungle, you have to cut the t-stat down to a crisp 72* for the rooms to dehumidify and of course they're as cold as heck.

    Another thing that exacerbates this, is that state law says that a damper has to be open to let in a % of fresh (read humid) air. I understand this b/c of potential CO emissions. Still, this does not help me. Papers curl, flooring buckles, girl's hair frizzes, and its a real b**** to put up with.

    Short of buying a dehumidifier (at my own expense, mind you) what can I do about an obvious stupid install????

    Thanks once again
    Rom

  2. #2
    Join Date
    Aug 2003
    Location
    Fort Worth, TX
    Posts
    11,086
    Having the air handler thoroughly cleaned is a great place to start. If it is plugged up with dirt/dust, it can't move as much air as it should. Not moving as much air as it should means not enough air volume of the room passes over the cooling coil to be cooled and dehumidified. Dirt/dust on the cooling coil itself acts as an insulator, preventing the cooling coil from removing as much sensible and latent (moisure) heat as it could.

    Clean 'er up and let 'er rip at 75^F, and see what happens.

  3. #3
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    66,773
    Besides the cleaning.
    The blower can set to low speed to help some.
    Also, a some what more restrictive air filter may help slow the air down, if the school won't slow the blower.
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  4. #4
    Join Date
    Jun 2003
    Location
    Florida
    Posts
    9,548
    You can start by having the blowers/ airhandler cleaned out and properly checked. I'm all too aware of today's OA requirements, which at 15 cfm/ person can add a large latent load on the system. The 4 ton sounds too small for the application, as it should be a staged system also to provide humidity removal. We also put sensors on our systems to open the O/a dampers only when the rooms were occupied....we used motion detectors w/ a time delay board.
    If everything was always done "by the book"....the book would never change.

  5. #5
    Join Date
    May 2007
    Location
    Naples, Fl
    Posts
    889
    Show the unit to a parent. email maintenence.

  6. #6
    Join Date
    May 2007
    Location
    DC Metro Area (MD)
    Posts
    3,350
    New Trane on an air handler from '93? Both 10 SEER?

  7. #7
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    How is the fresh air connected?What size duct,is it filtered?

    Is there an exhaust fan to pull fresh air in?

    We have seen some jobs that were getting three times the fresh air needed,due to the setup.

    Fan speed needs to be set,by testing of some kind,static and fan chart is one way.

  8. #8
    Join Date
    Mar 2008
    Posts
    205

    Got THAT ONE taken care of

    Quote Originally Posted by beenthere View Post
    Besides the cleaning.
    The blower can set to low speed to help some.
    Also, a some what more restrictive air filter may help slow the air down, if the school won't slow the blower.
    but that's wasn't y MO to do that. I bought (again at my own expense) 3M Filtrete Maximum Allergen (the 20 buck kind at HD) mainly b/c this thing spews dust thru the near-invisible filters the janitorial staff installs.

    Thanx Been, glad to that I might have helped my situation w/out meaning to.

  9. #9
    Join Date
    Mar 2008
    Posts
    205

    Whoa

    Quote Originally Posted by adrianf View Post
    Show the unit to a parent. email maintenence.
    That's a friggin good idea.

  10. #10
    Join Date
    Mar 2008
    Posts
    205

    Yep and

    Quote Originally Posted by RyanHughes View Post
    New Trane on an air handler from '93? Both 10 SEER?
    Yep. Our school system spares no expenses, we deaux things right-----the 3rd time!

  11. #11
    Join Date
    May 2007
    Location
    Naples, Fl
    Posts
    889
    Quote Originally Posted by RomulanSpy View Post
    but that's wasn't y MO to do that. I bought (again at my own expense) 3M Filtrete Maximum Allergen (the 20 buck kind at HD) mainly b/c this thing spews dust thru the near-invisible filters the janitorial staff installs.

    Thanx Been, glad to that I might have helped my situation w/out meaning to.
    That all depends on where the filter is in relation to the fresh air intake.

  12. #12
    Join Date
    Mar 2008
    Posts
    205

    Lets see.

    Quote Originally Posted by dash View Post
    How is the fresh air connected?What size duct,is it filtered?

    Is there an exhaust fan to pull fresh air in?

    We have seen some jobs that were getting three times the fresh air needed,due to the setup.

    Fan speed needs to be set,by testing of some kind,static and fan chart is one way.
    Fresh comes thur an open damper under the AH, it doesn't have its own filter but is combined w/the return air from the rooms

    No exhaust fan, I THINK the blower pulls in the fresh air too. Not sure.

    Good Q's I'll run 'em by maintenance

  13. #13
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    Quote Originally Posted by RomulanSpy View Post
    Fresh comes thur an open damper under the AH, it doesn't have its own filter but is combined w/the return air from the rooms

    No exhaust fan, I THINK the blower pulls in the fresh air too. Not sure.

    Good Q's I'll run 'em by maintenance
    Where is the filter,in the unit or at a return grille??

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