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  1. #14
    Join Date
    Mar 2003
    Location
    Cincinnati
    Posts
    7,977
    Are you sure one of your returns did not come loose under your home??

  2. #15
    Join Date
    Oct 2004
    Location
    Metro ATL
    Posts
    454
    I had the same thought as mattm. Especially if the ductwork is origional. But......what we really need is for a tech to take a few more measurements other than just the pressures to tell us if this unit is operating at full capacity.
    1. delta T across the evap coil
    2. superheat
    3. subcooling
    4. amperage on compressor and its FLA

    Preferably, these would be taken during the heat of the day when the unti is working hardest and when you seem to be experiencing problems

  3. #16
    Join Date
    Mar 2005
    Location
    Suppy NC
    Posts
    4,517
    with just pressures it is hard to tell what is going on inside your system. 285 on a 95 degree day may be high and may not be depends on how old the system is and the brand.
    what does consern me is the suction pressure at 60. i tend to think it should be up arround 70 or a little higher.
    there could be a resticcktion in the system and needs to be looked into by a competent tech. or your indoor coil is dirty and needs to be cleaned. one other thing you should look into is your return grilles if they are covered with dust and or by funiture clear them. what type filter are you useing and if it is one of the home depot high eff filters through it out and put in a standart one. make sure all of your registers are open even in rooms you are not using. you said he cleaned the out side coil but did he lok at the blower and or returns. i would like to see the suction pressure higher. subcool and superheat would make it a lot easer to see what is going on.

  4. #17
    tinknocker is correct. pressures just gives us a range. subcooling tells us how much refrigerant is in a system and
    superheat lets us know what problems the system is having.
    unit could be overcharged going by the fluctuation in suction. need temps to be sure.

  5. #18
    Join Date
    Aug 2004
    Location
    Tyler TX
    Posts
    676
    Did the tech say why the evap pressure was low?
    HVAC Contractor, Tyler Texas.

  6. #19
    Join Date
    Jun 2005
    Location
    GA
    Posts
    30
    So while we wait for hotinthesouth to respond, let me make sure I understand what is best to request during a service check.

    1. delta T across the evap coil
    2. delta T across condenser coil
    3. superheat
    4. subcooling
    5. amperage on compressor and its FLA
    6. pressure readings
    7. external temperature
    8. physical status of system, coils, etc..

    Does this about cover everything?


  7. #20
    Join Date
    May 2005
    Location
    Pasco County Fl
    Posts
    6
    I could be wrong, but it sounds to me like you may have a restriction somewhere in your system, as the high side and low side pressures are not in line with each other! Depending on what kind of metering device your system utilizes will determine the cure needed! If it is fixed, it may just be a simple cleaning of the orifice, but if it is a txv, it may be a little more complicated! Also, if a few people have put gauges on this system, non condensibles may very well be the culprit, as the possibility of introducing them to the system is possible everytime it is checked! If that is the case, have the liquid line drier changed, if in fact there even is one installed! Hope this helped in some way!

  8. #21

    more info

    I appreciate all the help, I will be out of town for the next 4 days and I am suppose to check back in with the tech. to tell him how things are going and I will try and get more of the info that you guys have been requesting and maybe we can figure this thing out. Until then, no one answered my question about the dye that one tech. put in, could that be the problem? also on a 95 degree day my unit got up to 75 inside and I know that sounds about right but answer me this, my unit on days like this runs about 14-16 hours straight, is this normal? My inside temp. was 75 at 2:00pm and dropped only 3 degrees in 9 hours, does this also seem right?

    thanks again

  9. #22
    Originally posted by mattm
    Originally posted by mattm
    Have a pro clean the coils.
    I will agree with mattm on this.
    I sure hope so... LOL

  10. #23

    Wink

    I have encountered this problem many times. It sounds like there may be duct leaks (return or supply) allowing the system to acquire excessive humidity from your crawl space. Have the technician take WET BULB temperature readings at the return of the indoor unit and again at the supply plenum (just after the indoor coil). This will tell us how much humidity is being removed across the coil. Then have him/her take the same readings inside the house. When compared, the temperatures from inside the house should be close to the temperatures at the indoor unit (less than 5 degrees would be acceptible). Be sure to specify that he/she takes WET BULB temperature, as DRY BULB TEMPERATURES WILL NOT WORK.

    [Edited by theredneckrev on 07-22-2005 at 07:49 AM]

  11. #24
    Join Date
    Apr 2004
    Posts
    7,680
    I'll take a stab at it.... Low airflow and overcharged to compensate for it.

  12. #25
    Join Date
    Aug 2002
    Location
    Office and warehouse in both Crystal River & New Port Richey ,FL
    Posts
    18,836
    Riskey diagnosis there Doc,as that rarely happens!

    hehehehe LOL!

  13. #26
    Join Date
    Mar 2005
    Location
    Suppy NC
    Posts
    4,517
    the dye will not hurt your system if left in. it is designed to be added and some guys put it in so if a leak shows up down the road it is easyer to find. worrie about what is wrong with the stetem the dye wont hurt it

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