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  1. #1
    Join Date
    Jan 2008
    Posts
    78

    Newly installed AC issues

    Folks

    Have posted questions in the past and have gotten great responses....so I'm coming back to the well

    I live in northern NJ, in a house that is about 2000 sq ft. and built in the 50's...lots of original windows with external storms.

    We had a system installed a few months ago, in a house that did not have central air in the past. Trane xl16i 4 ton, with 2 zones, (up & down)...

    the system imo just doesn't work right.. When it was 85 and humid, after 2.5 hours the house was still 78 degrees even though it was set to 70. When the sun is out and sunny, i can't get the system to 70..

    It seems like the comperessor is always going. the contractor has been here twice already, first time they said they needed to add more coolant because the run from the compressor to A/h was long...the second time they were on the phone with the factory and told me the second stage was not wired properly....I'm still not happy.... shouldn't a 4 ton system be able to get 1 floor really cold...even if the temp is in the 90's...since the 4 ton system is supposed to be suffficient for the entire house.

    Any suggestions as to what I should be looking for and what ? to ask the installer?

    thanks in advance

  2. #2
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,727
    Ask them how second stage is being controlled.
    By stat, or by zone panel.
    If by panel, do both zones have to call for it to go to second stage.
    Is it by timer.
    Is it really going to second stage when it should.
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  3. #3
    Join Date
    Jun 2008
    Location
    Phoenix, AZ
    Posts
    70

    Cool

    you could set both of your t-stats at 8 or 10 degrees cooler then what the current temp is then take temperature reading at the supplies/vents. Then set both t-stats for 1 degree under what the current temp is on the stat. For example, current temp inside house is 79 then set the t-stat at 78. Check temps at vents again. Then turn off one t-stat, check again... you can even go out to the unit and take off the panel to see what speed the unit is running in... high or low... This way you'll be able to tell if the unit and the zone control are working together or one is being hindered by the other, but like the last post was saying... sounds like it was not set up properly. Might only be staying on the low speed or certain zones aren't opening when they should... something along those lines...

  4. #4
    Join Date
    Jun 2007
    Location
    Round Rock
    Posts
    3,517
    It sounds as if you have other issues as well. What does your insulation look like? Original windows probably leaking air in and out. Insulation in walls? Installing a shiny, fancy new a/c system will not work unless the envelope of the house is good. It's like putting fancy wheels on an old beater. It isn't going to make it run any better.

  5. #5
    Join Date
    Jan 2008
    Posts
    78
    Quote Originally Posted by beenthere View Post
    Ask them how second stage is being controlled.
    By stat, or by zone panel.
    If by panel, do both zones have to call for it to go to second stage.
    Is it by timer.
    Is it really going to second stage when it should.
    I believe it is by timer...the solution this time around was to get rid of the 25 min delay for 2nd stage and to close the damper for external air...

    The system now sounds like a jet engine even if there is only a 1 degree diff between the set point and room temp..

    with a variable speed fan, shouldn't the fan speed change based on the on the temp diff between set point and room temp.

  6. #6
    Join Date
    Jan 2008
    Posts
    78
    Quote Originally Posted by bmathews View Post
    It sounds as if you have other issues as well. What does your insulation look like? Original windows probably leaking air in and out. Insulation in walls? Installing a shiny, fancy new a/c system will not work unless the envelope of the house is good. It's like putting fancy wheels on an old beater. It isn't going to make it run any better.
    I find this hard to believe....i've lived in houses older than this one that I was able to cool with a window unit.. so you think any house built before 1960 shouldn't have any air conditioning?

  7. #7
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,727
    Is it an external fresh air damper they closed. Or is it a bypass damper they closed.

    The VS blower varies its speed to maintain set CFM, not temp.
    What brand zone system did they install.
    2 stage A/C shold not be set to go to second stage by a timers.
    It should be done by either, the thermostats, or the number of zones calling.
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  8. #8
    Join Date
    Jan 2008
    Posts
    78
    Beenthere,

    thanks for your thoughts...they system is a trane xl16i, 2 stage system with a variable speed AH (sorry, don't have the brand with me)..

    My thought was the purpose of the variable speed AH was dependent on the temp diff between set point and room temp....now, it just goes on high and sounds like a jet engine most of the time. If not set point, what is the purpose of a variable speed a/h?

    The fresh air damper is closed...they also said they turned off the 25 min delay in going from stage 1 to stage 2.

    The chronology

    This system has had problems from the outset.

    first time I turned it on it couldn't get below 78 so they came out and assumed it needed more freon. how much they added I have no idea. When I called again because that didn't work, they told me that it wasn't going to second stage so they had to change the wiring.

    when it still didn't cool properly, they just turned off the first stage delay, (now it goes into stage 2 every time) and closed the fresh air damper and maxed out the fan...

    I'm desperate. shouldn't a 4 ton system cool a 2k aq ft house?

  9. #9
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,727
    Unless you have walls of windows or no insulation and drafts blowing though your house with the windows and doors closed. Yes, it should in NJ.

    Good chance its still a wiring issue. And they don't know how to wire it right with the zoning system.

    Got to wire it up by the OD units wiring diagram, not the ID units.

    A VS blower varies its speed to maintain set air flow. So as the air filter restricts from getting dirty, it speeds up to keep moving the same amount of air.

    There is a ramp profile that can be set to make the blower come up to speed slower.
    On Trane its known as Comfort R.
    They may not have enabled it.
    But until they correct the wiring issue, your not going to have a good working system.
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  10. #10
    Join Date
    Jan 2008
    Posts
    78
    beenthere,

    thanks for the info...what do you mean OD v. ID?

    Also--any concern they oversaturated the system with too much Puron?

    thanks agian...sorry to keep asking you more questions with every nugget you provide.

    You aren't in NJ by chance are you?

  11. #11
    Join Date
    Jul 2008
    Posts
    5

    Condensate pump mystery

    Our system is working fine. Except. It stopped a week ago when the overflow pan filled. It seemed the condensate pump (6 years old) had died. It was replaced. The new pump did not pump. Bench tests showed both pumps are fine. The line out of the condensate pump was flushed, then replaced. The pump works once or twice then "bubbles up" and doesn't work again. For the last week we've had the condensate pump routed into a bucket which we empty every few hours, depending upon the temperature. The condensate pump need only pump a foot or so vertical, the the line runs 25 feet or so across the attic to the side of the house, then out to the ground. The system works well, but hauling those buckets is a pain. What kind of physics is involved I do not know.

  12. #12
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,727
    ID= indoor.
    OD= outdoor.

    An over charge is always possible. But that wouldn't cause it to only run in second stage.
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  13. #13
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,727
    Was the whole drain line reran, or just part of it.
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