Replydid 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.
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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.
Professional Member*
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.
Professional Member*
There are many "Master Techs" on here regularly. What part of the country are you in?
Banned
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..Originally Posted by Sjzinkc
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.
Banned
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.
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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.
Banned
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.
God Speed, Jim. We'll miss you - 2-26-23
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
God Speed, Jim. We'll miss you - 2-26-23
Missed the part where you said they only replaced the outside part.
It won't work.
New Guest
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.
AOP Committee/Professional Member*
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...
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udarrell
Professional Member*
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
Professional Member*
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.
Professional Member*
The A coil went out,as in sprung a leak? They would have replaced it at the same time as changing the condensing unit to a 3 ton. More then likely you have 1.5 ton duct on a 3 ton system now which is the root of the problems.
Regular Guest
I hate seeing uneducated home owners being taken advantage of by incompetant contractors.
You have many issues, all of which can be resolved by switching the outside unit back to a 1.5 ton that matches the evap coil. Get the builder to come out with a hvac contractor and make them do a heat/load calc on your house. I can tell you that 3tons is more than likely too big for your home.
Professional Member*
How can we assume that replacing the 1.5 ton outside unit with at 3 ton is the issue....without knowing what the inside unit was to begin with?
It could very well have BEEN a three ton, with the wrong outside unit?
We all know what Tony Randall said about when you assume....
Technical incompetence is NOT a sales tool....
Professional Member*
In what way? That would be quite typical here....
Technical incompetence is NOT a sales tool....
Banned
1.5 to 2 max here in Houston and we've got you beat like you were in a third world country.In what way? That would be quite typical here....
<cheers>
AOP Committee/Professional Member*
I agree John, it would be typical there; however, there are effective ways to make a 2 or 2.5-Ton to handle a new retrofitted reduced heatload.In what way? That would be quite typical here....
I doubt it could be retrofitted enough so a 1.5-Ton could do the job; but I've seen some amazing things.
You won't know until the Home Energy Audit, Retrofit, M-J, & ductwork airflow manual D is completed.
Like I said we're just speculating; a Home Energy Audit along with the cost effective retrofits, & only then a manual J should be performed so the correct size is installed with the best ROI for the home owner.
We can only make; possibly off-beat; suggestions, contractors on the ground have to do the right things in the right sequence to end-up with the optimal end result...
Last edited by udarrell; 05-01-2011 at 04:02 PM. Reason: Clarifications...
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