Page 2 of 6 FirstFirst 123456 LastLast
Results 14 to 26 of 66
  1. #14
    Join Date
    Jan 2005
    Location
    SE Florida
    Posts
    220
    my guess would be that he didn't use a charging chart when charging your system and now you're slightly undercharged. '
    or perhaps a txv was mistaken for a orifice, but before you go any further stick that temp prope in your supply plenum and read the temp of that. when that's done put it in the return.

  2. #15
    Join Date
    Feb 2003
    Location
    Huntsville,AL
    Posts
    4,125
    what is the temp in the house when outside is 95F? what RH%?

    machinery running all the time usually is at or near full effeciency! starting & stopping shortens machinery life.

  3. #16
    Join Date
    Apr 2004
    Posts
    7,680
    Whats the airflow? Chances are no one has even considered this. Rarely is it too much but it could be. High airflow could also cause a low temperature drop. High humidity, which also seems to be missing from the data will cause low temperature splits. Leaking ductwork pulling in attic air is also culprit. Low airflow can cause a tech to overcharge the unit which will reduce the capacity of the machine.

    77 degrees where? At the inlet of the coil or at the return grille? 67 where? At the outlet of the plenum or at the registers.

    What was your electrical usage last year? Has the rate gone up? Have the degree days gone up? Its too bad you didnt have a load calc or anyone look for infiltration air.


  4. #17
    Join Date
    Aug 2005
    Posts
    18
    Supply is 77degrees and return(vents?) is 67degrees

    Outside temp97 outside humidity 78.
    Inside temp 77 inside humidity 56.

    Air handler has high air flow should I slow it down?

    System is running like 40minutes on and 18off. House is cool but still I feel the vents should give me below 60 degrees.

  5. #18
    Join Date
    Apr 2004
    Posts
    7,680
    Lets assume you have some gain in your ducts of even 2 degrees in both return and supply. That would be 79 return at the unit and 65 at the outlet of the coil. Thats a 14 degree split. High humidity along with too much airflow is going to make that so. We dont know the airflow so I dont suggest messing with it. A good tech ought to be able to properly troubleshoot it. Arbitrarily lowering the airflow can cause compressor damage among other problems.

  6. #19
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,272

    Question Run Time, AHU Plenum Temps

    Originally posted by joe 40 Air handler has high air flow should I slow it down?

    System is running like 40 minutes on and 18 off.
    Maybe, but you have not provided the the current air handler Plenum temperature and air flow, Have you?

    What is 'High' air flow?

    If the air flow is slowed down,
    will the air handler and plenum be more
    susceptible to sweating?

    I assume the run time applies to the Afternoon (~11 AM to ~7 PM). It appears that this system is slightly oversized, with 56% R.H. and moderate to lower-than-normal run times.

    [Edited by dan sw fl on 08-22-2005 at 09:41 AM]
    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

  7. #20
    Join Date
    Aug 2005
    Posts
    18
    Thanks for replying but I'll just wait for the a/c tech if he ever gets here. Wife is getting inpatient cause she wants cold air out of the vents!

  8. #21
    Join Date
    Jun 2005
    Posts
    171

    Talking

    Is the system properly charged?

    What are the gas pressures at ambient temp?
    Subcooling and superheat?

  9. #22
    Join Date
    Jan 2005
    Posts
    340
    Originally posted by joe 40
    Do you think I should have gotten a 2 1/2 ton? That's what I took out cause tech told me it was too small!!
    Why did he say that?

    http://hem.dis.anl.gov/eehem/95/950509.html

  10. #23
    Join Date
    Jan 2004
    Location
    Atoka, TN
    Posts
    42
    Make sure your return ducts are sealed and not pulling in hot attic air.

  11. #24
    Join Date
    Aug 2005
    Posts
    18
    It's 99degrees outside and I have the unit set at 78degrees. The vents air is marking 70degrees!! And of course, the tech hasn't come! This system is a 3ton and I should be freezing my butt off. If this system is oversized it should be turning on and off constantly and it doesn't.

    Ducting is not leaking, so they say!

    Presures are 270 high, 82 low .

  12. #25
    Join Date
    Nov 2004
    Location
    SW FL
    Posts
    6,272

    Question What

    Originally posted by cri3541
    Make sure your return ducts are sealed and not pulling in hot attic air.
    And keep the windows closed.
    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

  13. #26
    Join Date
    Aug 2005
    Posts
    18

    Angry

    Tech still hasn't come. They still say a 3 ton is good for my house and not too big. Well, I told them over the phone if they can't get my vents to throw 58degree air then I want that system off!! My old unit would throw 52degree air and it was only 2 1/2 ton. I guess I got suckerd on buying a new unit!!

    What are the odds on getting my money back? (That's what I thought!!)

Page 2 of 6 FirstFirst 123456 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event