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Thread: Input please!

  1. #1

    Input please!

    We have been dealing with cooling issues in our home since moving into the new construction in 2005. Our 1.5 ton ran constantly without successfully keeping the home cool, so we opted to upgrade to 3 ton when the a-coil went out in 2008. Since then we have had the txv valve replaced 4 times and the unit is freezing up again! This is the typical problem that results in a new valve. Last year the service/installation company had a "specialist" from Carrier come run some tests but we have never received the results, though we have asked. Also the owner of the heating and cooling company happens to be part owner in the construction company that built our home so I am afraid we would not be told of any possible problems with the duct work. What could be making all of these valves fail year after year? I find it hard to believe they are faulty at this point. Is there such thing as a master hvac tech that could diagnose and fix our real problem? If so, how do we find one? Any input is greatly appreciated.

  2. #2
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    did you replace the furnace/air handler with the A/C? Why did you double the zize of the A/C? Could be an airflow issue. If original duct was made for 1.5T and you now have 3T it isn't working right.

  3. #3
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    There are many "Master Techs" on here regularly. What part of the country are you in?

  4. #4
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    Quote Originally Posted by Sjzinkc View Post
    We have been dealing with cooling issues in our home since moving into the new construction in 2005. Our 1.5 ton ran constantly without successfully keeping the home cool, so we opted to upgrade to 3 ton when the a-coil went out in 2008. Since then we have had the txv valve replaced 4 times and the unit is freezing up again! This is the typical problem that results in a new valve. Last year the service/installation company had a "specialist" from Carrier come run some tests but we have never received the results, though we have asked. Also the owner of the heating and cooling company happens to be part owner in the construction company that built our home so I am afraid we would not be told of any possible problems with the duct work. What could be making all of these valves fail year after year? I find it hard to believe they are faulty at this point. Is there such thing as a master hvac tech that could diagnose and fix our real problem? If so, how do we find one? Any input is greatly appreciated.
    Just to get a ball park figure, how many sq feet is your home and is it single story or double? I know you said one and a half tons originally so I'm thinking single but stranger things have happened..

    Without that info, yes, your cubic feet per minute (CMF) has to be evaluated and re-evaluated as cfm moved for 1.5 tons is pretty much half of that needed for 3 tons. This would mean that all ducts, return as well, would have to be accordingly up sized.

    Your builder/hvac guy knows this and I hope he wasn't the one who just installed a bigger unit (unethical business practises in my opinion) as never should a bigger "system" be installed without instant gratification of air flow to accomodate for true and total system performance.

    It's like trying to put a square through a triangle.

  5. #5
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    Let's talk velocity. Since this bigger and useless system was installed, has the air coming from the registers been more audible? Does it push out harder than the 1.5 ton did? The return? Is it wheezing, pulling, struggling?

    I can answer that for you. I'm 100% sure it is even if you can not tell. That would mean that since the air is trying to be pushed out it is being restricted in the plenum and on it's way out, equalling a higher static pressure which negates your systems ability to properly boil over refrigerant and/or dehumidify the air.

  6. #6
    We were the only home in the neighborhood, exact floor plan, that wad 1.5 instead of 3. This particular company as well as a second opinion, hired by us, convinced us that upgrading would work. They only replaced the outside unit. We are in Kansas City, MO.

  7. #7
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    Quote Originally Posted by Sjzinkc View Post
    We were the only home in the neighborhood, exact floor plan, that wad 1.5 instead of 3. This particular company as well as a second opinion, hired by us, convinced us that upgrading would work. They only replaced the outside unit. We are in Kansas City, MO.
    Well we need to know what size evaporator coil and furnace you have. Is it a furnace or is it an air handler?

    Model numbers of all equipment will be needed, inside and out.

  8. #8
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    If they just increased your unit size from 1.5 ton to 3 ton without redoing your entire duct system. Then your duct system is grosly under sized. Its also very doubtfull you need a 3 ton A/C.s
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    How many times must one fix something before it is fixed?

  9. #9
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    Missed the part where you said they only replaced the outside part.


    It won't work.
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  10. #10
    Oh my, you're comments are very much appreciated but overwhelming at the same time. I am in the medical field and admittedly know very little about any of this. Unfortunately, our lack of knowledge has clearly been taken advantage of. How am I to find someone I can trust? Should most techs know replacing the unit would be pointless? Who does one hire to replace ductwork? Our home is 1650 sq. Ft, front to back split. I will post model numbers when I get home tonight. Thanks.

  11. #11
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    Quote Originally Posted by Sjzinkc View Post
    We were the only home in the neighborhood, exact floor plan, that wad 1.5 instead of 3. This particular company as well as a second opinion, hired by us, convinced us that upgrading would work. They only replaced the outside unit. We are in Kansas City, MO.
    So, they didn't replace the indoor evaporator coil?

    What tonnage was/is the coil that matched the 1.5-Ton condenser?

    Most are matched with a 2-Ton coils; I wouldn't just put a 3-Ton TXV on a 2-Ton coil on a 3-Ton condenser.

    Everything has to match the condenser's tonnage Rating: the evaporator coil; the Air Handler; duct system; air flow, etc.

    What is the BTUH output of the furnace?
    Is it electric, gas, or Oil heating?

    Kansas City Climate; 2.5% summer design is 96F DB; 74F WB or only 35% RH.
    At 35% RH the evaporator should be absorbing a high percent of sensible heat, making it easier for a smaller unit to bring the temp down.

    You never know; your home & other factors could have been retrofitted to greatly reduce heat-gain & also improve the 1.5-Ton's output.

    I have a little building science knowledge, & improvements on both halves of the system equations - could allow for surprising downsizing from the neighbor's 3-Ton systems.

    However, 2-Ton may have been a better choice; just wild speculation, as we don't have enough information or test data, to even guess...

  12. #12
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    3 tons on a 1650 sq ft house is a joke.
    Sounds like you have several problems.
    I would find a good contractor to do a complete evaluation, and back charge to the builder.
    "Hey Lama, hey, how about a little something, you know, for the effort." And he says, "there won't be any money, but when you die, on your deathbed, you will receive total consciousness." So I got that goin' for me, which is nice. - Carl Spackler

  13. #13
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    Quote Originally Posted by Sjzinkc View Post
    Oh my, you're comments are very much appreciated but overwhelming at the same time. I am in the medical field and admittedly know very little about any of this. Unfortunately, our lack of knowledge has clearly been taken advantage of. How am I to find someone I can trust? Should most techs know replacing the unit would be pointless? Who does one hire to replace ductwork? Our home is 1650 sq. Ft, front to back split. I will post model numbers when I get home tonight. Thanks.
    That unit is bound to be too big. using the old indoor unit and ducts was a mistake!!!

    You likely have too little air flow in addition to having a bad mismatch in equipment.

    The indoor & outdoor units are supposed to be matched to work together. Yours are not likely a matched set and if they worked well together it would be a miracle.
    Remember, Air Conditioning begins with AIR.

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