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  1. #1
    Join Date
    Jul 2008
    Posts
    7

    Need help from the experts please

    Have gone through and looked at previous posts and just don't see one that quite describes my problem.

    I will try to be brief.......Have been with same HVAC folks under full service contract since 1998, all their techs are NATE certified. When we moved in 01/07, we brought them along to take care of things at our 'new' house which was built in 2001.

    I live in Atlanta...hot and humid summers. We have 2 units, one up and one down. Have had no real problems keeps temps at 76-78 during the summer months. When we had our summer '07 inspection I was told that the freon was a bit low on the upstairs unit so they put some in. Same situation at the beginning of this summer's inspection, a bit more freon.

    Quit cooling 48 hrs ago. Checked things out and found out that unit outside was not on. Checked circuit breaker and it had flipped off. Reset breaker, unit came on and all was well and cooling. Approx 3 hrs later, outside unit quit working again and circuit breaker (the one inside the house NOT the breaker by the unit) had flipped off again. I tried one more time, outside unit ran for about 1.5 hrs before shutting down again. At this point I just turned the air off at the thermostat.

    My HVAC guy is coming out this afternoon and I would like some feedback on what things he should be checking for and maybe some things I need to be asking.

    Appreciate your help!
    carole

  2. #2
    Join Date
    May 2007
    Location
    DC Metro Area (MD)
    Posts
    3,371
    Instead of having them add freon on a regular basis, which is not good for the system, ask them to find the leak and repair it if possible.

  3. #3
    Join Date
    Jul 2008
    Posts
    7
    Ryan,

    thanks for the suggestion!

    would a leak cause my condensor unit to flip off my circuit breaker?

  4. #4
    Join Date
    May 2007
    Location
    DC Metro Area (MD)
    Posts
    3,371
    Quote Originally Posted by taxicat View Post
    Ryan,

    thanks for the suggestion!

    would a leak cause my condensor unit to flip off my circuit breaker?
    Hmm... I'll have to let one of the experienced pros on this site answer that question. I'm sure you'll get some more suggestions shortly...

  5. #5
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,876
    Maybe instead of being low on refrigerant, it has a dirty coil. And now with all the extra refrigerant, its tripping the breaker during the hottest high load times of the day.

    Since they are NATE certified. They should be checking SH, and SC when they check charge. Ask them to right down that info on the invoice.
    With amp draws, temp difference across the coil. Indoor drybulb and wet bulbe temps. And outdoor temps.
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  6. #6
    Join Date
    Jul 2008
    Posts
    7
    thanks for your response!

    I was told earlier this summer that 'pressures' indicated the low freon and that the addition brought them up to good levels???

    a couple of questions....

    what do SH and SC indicate? what charge should he be checking?

    where is the coil located? what is it's purpose? what will the temp diff across the coil tell us?

    what are the bulbs? purpose? dry and wet bulb temps?

    what can I say......I'm pretty nosey, LOL

    appreciate all your help!
    carole

  7. #7
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,876
    The indoor coil is where your indoor air exchanges heat with the refrigerant.
    If its dirty, or has low air flow across it, the pressures will be low. And too many techs just add gas untill the low pressure comes up higher. Over working the compressor.

    SC, and SH, tells us what state the refrigerant is in, and where it is in that state.
    The temps, wet bulb and dry bulb tell us what kind of a load the system is working against.
    High cooling load, low cooling load.

    Temp difference across the coil varies with the load conditions, and amount of air flow.

    No one reading tells the whole story.
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  8. #8
    Join Date
    Jul 2008
    Posts
    7
    beenthere.......thank you!

    couple of more questions please about the coil maybe being dirty.......how does this happen? can it be cleaned? does low pressure always mean it's dirty? where is the coil located? if it can't be cleaned, what's the fix?

    I would think that this would be part of the twice yearly inspections, along with the other stuff you mentioned?
    Or maybe only when there is a problem?

    carole

  9. #9
    Join Date
    Feb 2008
    Location
    Western NC
    Posts
    2,504
    Yes the coils should be inspected during these regular appointments. And depending on your contract, also cleaned.

    The pressures of the system mean nothing. The levels mean everything. And a combination of indoor temps, outdoor temps, static pressures, suction pressure, head pressure, superheat and subcooling determine whether or not the system has a low charge....

    The coil is located in your Air Handler(or furnace more commonly known as). This coil could be dirty, the blower motor could be dirty, the fan wheel could be dirty, the ductwork could be restricted, the ductwork could be open to unconditioned air, the condenser coil could be dirty, there could be a refrigerant restriction, there could be a non-fuctioning metering device.....



    There is a lot of things that your tech needs to address. He needs to take all the measurements and provide an accurate and detailed diagnosis, not just pressures low. This would indicate to me that he is not NATE certified. If he was, I would hope he takes the time to do things right....



    How do you know the techs are NATE certified? How do you know the one you got was certified?
    I fully support the military and the War on Terrorism.


    If you don't know, then don't do. If you don't know and still do, then be prepared to pay someone else a lot to undo what you did and then do it right.

    If you do know, then do. But do it right. Otherwise, you may not be doing it long.

  10. #10
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,876
    What teh vet said.

    They should be checking the coil when they come to inspect it.
    And that can be done easily.
    Mention it to them the next time.
    You want the SH, and SC and ambient conditions listed on your copy of the work order.

    You may not be getting what your paying for.
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    How many times must one fix something before it is fixed?

  11. #11
    Join Date
    Mar 2008
    Location
    Central Maryland
    Posts
    246

    Same here...

    I had a similar experience, my system would cut out when stressed or switching between heat and A/C modes (heat pump). Turns out it was the combination of lint on the indoor coil, grass in the outdoor coil, and 2 extra unneeded pounds of refrigerant added after it was misdiagnosed.

    -HF

  12. #12
    Join Date
    Jul 2008
    Posts
    7
    WOW......thanks all....lots of great info!

    I am now totally stumped! System is working just fine now. Kinda like you're really sick and by the time you get to the doctor's office, you feel great.

    Before I left for work yesterday am, I turned the system on to re-create what's happening for the tech to see for himself. Came home to meet tech and the upstairs is beautifully cooled and as of this am, still working like it should. I cancelled the service call.

    Y'all have really opened my eyes.....I am calling our HVAC company this am and will request a list of what they actually do when they come twice a year to inspect. Also, a copy of those inspections (pre-purchase, 2 in 2007 and 1 so far this year) hopefully with readings.

    As far as NATE certified, it is noted on their website, on their workorders and I verbally confirmed that the tech that was supposed to come out yesterday was certified. They stated to me that ALL their techs were certified.

    I'll report back with what I find.

    I really do appreciate all of you taking the time to respond to me!

    carole

  13. #13
    Join Date
    Feb 2008
    Location
    Western NC
    Posts
    2,504
    Quote Originally Posted by taxicat View Post
    WOW......thanks all....lots of great info!

    I am now totally stumped! System is working just fine now. Kinda like you're really sick and by the time you get to the doctor's office, you feel great.

    Before I left for work yesterday am, I turned the system on to re-create what's happening for the tech to see for himself. Came home to meet tech and the upstairs is beautifully cooled and as of this am, still working like it should. I cancelled the service call.

    Y'all have really opened my eyes.....I am calling our HVAC company this am and will request a list of what they actually do when they come twice a year to inspect. Also, a copy of those inspections (pre-purchase, 2 in 2007 and 1 so far this year) hopefully with readings.

    As far as NATE certified, it is noted on their website, on their workorders and I verbally confirmed that the tech that was supposed to come out yesterday was certified. They stated to me that ALL their techs were certified.

    I'll report back with what I find.

    I really do appreciate all of you taking the time to respond to me!

    carole

    NATE certified is a very broad term. There are several NATE certifications that one can obtain. There are also 2 certifications for each category. 1 for service and 1 for installation.

    In fact, here is a list from the NATE website on all the certifications.


    The NATE Family of Tests

    To become NATE certified choose either SERVICE or INSTALLATION path and take

    Core Service
    Core Installation


    PLUS ONE SPECIALTY BELOW


    Air Conditioning Service
    Air Conditioning Installation
    Air Distribution Service
    Air Distribution Installation
    Air to Air Heat Pump Service
    Air to Air Heat Pump Installation
    Gas Heating (Air) Service
    Gas Heating (Air) Installation
    Oil Heating (Air) Service
    Oil Heating (Air) Installation
    Hydronics Gas Service
    Hydronics Gas Installation
    Hydronics Oil Service
    Hydronics Oil Installation
    Light Commercial Refrigeration Service
    Commercial Refrigeration Service





    All those in red are certifications. And each has its own test.



    Good luck with everything. Ask questions as they arise. We are here to help best we can
    I fully support the military and the War on Terrorism.


    If you don't know, then don't do. If you don't know and still do, then be prepared to pay someone else a lot to undo what you did and then do it right.

    If you do know, then do. But do it right. Otherwise, you may not be doing it long.

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