Not really a DIY but questions for you AC pros.

I am in a brand new, 4.5 year old house and am to the point of replacing the AC already.  I've had 23 service calls in the 4.5 years.  I've gone through 3 eval coils in the attic and I'm on my 2nd outside coil.  Now it's leaking again.  AC guy did a pressure test, but I'm on vacation so I'm waiting to here what failed this time.  

I have a Goodman 3 ton.  My house is 2250 sq ft.  The living room has 17 ft vaulted ceiling, bedrooms are about 13 ft vaulted.    I have 3 bedrooms in the front of the house that are almost impossible to cool down with the current AC.  I normally close off 2 of them so that all the air goes to one where my kid is.  

AC guy comes and takes a look.  He recommends a 3.5 or 4 ton.  What do you guys think.  Everything I've read says to go slightly under what the calculation says --- so 3.5 ton???

He also sees a junction box in the attic which he suspects is the reason those three rooms are getting little air.  Suggests putting in a duct fan (since it would cost a lot to redo duct work)

Then Brands:
He suggests a med or top line Tempstar (made by International Comfort, Carrier) or Carrier.  He said that Carrier now makes it a PITA to do warranty work for warranty coils etc, and now it costs more in labor to do their work.  Says Tempstar has a better warranty and would be 4500 to 5k.  I haven't got an exact estimate yet.

I'm not looking to break the bank on brands.

Any advice.

a couple of questions.
1. why isn't your home bulider taking care of this warranty work?
2. did someone check your duct work to see if it will handle a larger air mover?

in texas you go a little under so it runs longer to remove humidity. so it doesn't cycle on and off too much.

however, .5 a ton may not be enough if you have that much of a problem keeping things cool. I would get a second opinion on it.

more insulation or next time you have your roof replaced due to hail, add the radiant barrier decking instead.

never heard of temp start.
have had trane, carrier and currently have lenox and prefer that one.

but I would still be on the builder before I put money out of my own pocket.

First thing you need to do is call another A/C repair company.  One of my employees was quoted $8000 for a new whole house unit.  I told him to call around and get bids and let the shops know he was price shopping.
He got one for $3800

Another employee was working in the A/C field between jobs and said that the go to units for longevity are the Trane brand and one other made by the same company.  Can't remember now, but I too am on borrowed time with one of my units.

As far as the builder, they cover the first year of issues.  All the parts are still under warranty however  labor isnt.  Personally i want to take a bat to this thing and replace it.  

He just told me the leak is in the evap coil.  Less than 2 yrs old.  

The first quote i got was from the company who put it in, bodine scott.  They quoted 6500 to 7k and they were the ones who worked on it abot 18 of the times so im done with them.  

The vents will handle up to the 4 ton they said, i just rather not go too big.

Trane/American Standard are at the top, with Lennox in the ballpark. 3 tons sounds way undersized but we don't have enough information to make a call there.

Edit: Unless you have a very well insulated house, you are probably undersized. If you are in central or south Texas especially. The previous post about under sizing is false, unless it's just worded wrong. If the only calc the contractor does is "under sizing" to handle humidity he's doing it wrong. You can select equipment for both latent heat(humidity) and sensible heat(air temp).

What you are looking for is a Trane or American Standard variable speed system with zoning.  Always the right size and always the right air flow.

Very true, but also top dollar. Best bang for the buck is probably a two-stage condenser with variable speed fan. OP, chances are with your air mass/vaulted ceilings you need more cooling capacity, you need a contractor who will do the load calcs and not rule-of-thumb it. Budget matters here too, like others have said if the problems started within the builders warranty period you should be getting some financial help with this.

Read the sticky above.
Pay attention to this advise from a pro. I did and have been very happy.

As said above get a heat load calc.   Also I would look into the Trane inverter driven compressor w/ variable speed indoor section

I would also give the mini split lines such as Mitsubishi and Daikin a look, they both have 3 ton 4 zone units and a 4 ton 8 zone unit. Depending on what you have for heat now they could be your heat for the winter. Just get them sized for your heating needs. They are inverter driven so they came be oversized on the cooling. The separate temps controls for the 3 bedrooms you have problems with. The mini split line will also be quieter both inside and outside. So much that you have to be beside them to hear them run. They will cost more but face it your electric rates are only going up, and if you are heating with some type of electric heat now your electric bill will go down

Check the local electric company for any rebates, some areas give pretty good rebates or interest free loans, for certain equipment

Thanks.  Ill take a lok at them.  As far as heat is concerned, its pretty much never been used.  I'm in So Tx so we tend to raise the windows during the winter.

Amana is very good.

We are very satisfied with ours.

I just got an Amanda system installed for $3500 .. 3.5 ton..working good in humid georgia

Until they stop.   Sure it's under warranty, but everything begins with "well we gotta drain the refrigerant and refill".   900 dollars later you start working on the problem and it's not covered under warranty.   Just parts and labor.

Yep, been there. done that!  My next one will be a Trane or American Standard.

I live in a house built in 1873. Last year I had AC installed. It cost me $25000 to have it done. I have baseboard heat, that didn't help out the cost any.

quit dumping money into an obviously bad install, get a pro to do a new install and hope its done right.

A good install is more important than what brand.

Even a Goodman (cheapest of the cheap) can last if the install is well done.

The biggest problem I see over and over (PE) is NOT putting a hard vacuum on the system and letting it sit long enough to pull ALL the water vapor out.
Overnight is a good starting point.

It takes a lot of time tom move the last little bit of vapor out.

And make sure the vacuum pump oil is new.
It really matters.

you shoudnt have to leave the pump on over night...


triple evac. break it on the 3rd time with refrigerant until around 1-2ish lbs just so your not in a vacuum so you dont suck in more shit, before you evac it for the last time and charge it.

micron gauge down to 500 and holding, your good to go.  LL drier will take care of the rest of it you couldnt get out, but the triple evac and break with refer the last time helps ALOT

trane, lennox, and carrier is good shit.
buy once cry once

goodman is okay. i wouldnt use it only due to working for a company that is a lennox dealer...

The mass flow rate at high vacuum gets horribly pitiful;.

You are  pulling on damn near nothing.

I usually work on specialized industrial systems.
24 hours of hard vacuum with a micron gauge is nothing.

were talking residential ac man.

not commercial/industrial new installations which hold well over 900lbs of gas with a loop system the size of a common grocery store or larger, in which i do work on....

goodman and Amana are both the same, now owned and built by Daikin.

Goodman is notorious for leaks. we had to send a tech into the warehouse and pressure test 5 coils before we got one that was not leaking. hopefully things will get better with their new stuff

***********************Ok so here's a little update****************************

They did a pressure test on the outside coil, the line, and the evap coil.  The leak was in the evap coil.  I had it replaced and also had the installer and Goodman come to the house and do a site visit.  

The old coil had a leak in it towards the top, middle area of the coil.  Goodman tried to pass the blame originally but once they saw where the leak was the installer was able to point at them.
Then goodman came back and said that the only reason it would be leaking there is due to a high amount of VOC's in the air eating away the coil.  He suggested putting in a UV light to neutralize the air.  From what I could find, that only kills bacteria and  microbe growth on the coil.  

Does this work or is he BS'ng me?

Now a month later, the AC went out again--Not cooling the house down.  I'm pretty sure it's another leak.  This is getting old real quick.

Eh... I got UV lights in my system, downstream of the coil.  They are in the far corner of the outlet manifold box.  I'm pretty sure the Goodman guy is giving you a line of crap about VOC's eating up his equipment.  If that's the case, I think you would have eye and throat problems, coughing, headaches ect. as well as damage to copper wiring and other corrosion problems noticeable in the house.  Would a UV light help?  Very possibly, but I've also heard it's hard on wiring and exposed epoxy components, which is why mine is FAR away from that kind of stuff in my system.  I'm down with the other people who have said your brad is a bit sketchy on QC.

Goodman is known for leaks, but they are many things in a house that can cause it. a bad electrical ground, sulphur well water, too much chlorine, Chinese drywall.



on one job we found a pool man had been putting  bottles of pool acid with loose tops in the air handler closet

Rheem

I have a leak in my evaporator coil as well.  I didn't notice until last week when it was 110+ with the heat index outside and my AC wouldn't cool below 82 or so when the thermostat was set to 78. It eventually could get there at the wee hours of the morning.

A service guy came out and put more freon in the system (4 pounds) but I'm waiting until the temps cool off outdoors so that I can have a friend come by and fix this.  He said he'd find the hole (if indeed it is in the evaporator coil) and replace the part, then recharge with freon.  So I really just bought a bandaid to get me through another few weeks until I seek a permanent solution.  Right now with the heat everyone is eaten up with service calls and I'm not about to ask a buddy to get out thre in this mess (he's 74).  

I'm not willing to replace this unit until he tells me it's time.  He said he's seen units far older than mine that are still working.

You have a better pump than a three stage? (not that the third stage pulls that much further).
New oil in the pump.

Do it right and it lasts a long time.
The smallest leaks show.

Pressure testing would be better but most gasses have enough temp variation to make it not as precise as we would like.
Vacuum testing pushes seals the 'wrong' way.
Nothing significant on hard joints (brazed) but a real issue on 'soft' joint (anything with ANY kind of elastomer like a Schrader valve)).

When the gas is a human hazard you seal really really well.

It is not 'required' for simple residential systems but they sure as h*ll last longer.