New Variable Speed HVAC Can't Keep Up?

[TangoFoxTrot]

My brother just purchased 3 new AC units for his home, (1)Trane XV18 and (2) XR17s.

He said he can't get the units to cool him home down properly without overshooting, he basically has to set several degrees below what he's comfortable at to get it to where he wants it. And all the other units in the house have to be going also. He doesn't really have the ability to zone control.


He called the outfit out and they said that variable AC units don't cool downs as well as traditional single speed units and it's just something you have to deal with. That sounds like a load of BS to me, but was wondering what others would say to that excuse.


He spent something $28k for these systems, and now he said the old units worked better. His house is a modern, well sealed home.

Did they simply not size the units correctly? Was a reasonable remedy for the situation?

 

[danski0224]

I'm assuming that there are also new air handlers or furnaces?

Is a communicating OEM thermostat required to get the equipment to operate correctly or use all features?

First thing I'd tell him to do is read the instruction manual, especially the part about airflow setup for cooling.

Double check wiring.

An improper setup is common.

If the switches are wrong, it won't perform well.

I'd guess that something isn't setup properly. If the installing contractor won't make good, call Trane.

 

[LS6 Tommy]

The HVAC company is full of it. Capacity is capacity. At full load it doesn't matter if a compressor is vaiable or single speed. If the sizing is OK, something is not setup correctly.

Tommy

 

[TangoFoxTrot]

I'm assuming that there are also new air handlers or furnaces?

Is a communicating OEM thermostat required to get the equipment to operate correctly or use all features?

First thing I'd tell him to do is read the instruction manual, especially the part about airflow setup for cooling.

Double check wiring.

An improper setup is common.

If the switches are wrong, it won't perform well.

I'd guess that something isn't setup properly. If the installing contractor won't make good, call Trane.

Everything is new, even the thermostats are the Trane models.

Is this something a consumer can "fix" in a settings menu?

For example, to get the place to cool to 76 degrees, he has to leave it on all day at like 74, and it never hits 74 degrees during the day.

 

[TangoFoxTrot]

The HVAC company is full of it. Capacity is capacity. At full load it doesn't matter if a compressor is vaiable or single speed. If the sizing is OK, something is not setup correctly.

Tommy

That was I thought as well, but this "tech" supposedly said the problem with the variable flows is they just don't cool down places as well as single speeds.
It seems pretty clear they messed something up and are now just lying.

This is a big, reputable outfit that's been around for several decades and is likely the biggest installer in the city. Sounds like he needs to go up the food chain, especially since he dropped like $28,000 for all of this and this s the answers they are giving him.

 

[driftpin]

I agree something isn't right. We have a Lennox MC25-060 variable speed, and it works fine, it cools well, no-need to 'overshoot' to get it to cool properly. 3,000 sq ft CBS construction home.

I hate to say it, but time to get an attorney involved, their attitude is unacceptable. If you want to play the social-media game, don't exaggerate, don't lie, but companies really don't want the bad P.R. on facebook or wherever.

 

[danski0224]

Everything is new, even the thermostats are the Trane models.

Is this something a consumer can "fix" in a settings menu?

For example, to get the place to cool to 76 degrees, he has to leave it on all day at like 74, and it never hits 74 degrees during the day.

Possibly, but probably not.

The whole installation needs to be verified.

The thermostats may not be wired or set up properly.

The airflow switches on the furnace board may not be set up properly.

The TESP (Total External Static Pressure) needs to be checked so the airflow can be verified against the manufacturer tables in the instructions, per the DIP switch settings (or, whatever the equipment will configure to based on TESP).

Some communicating equipment is "self-configuring", if it is wired and set up properly.

If the rated capacity is the same, or even somewhat smaller, performance should exceed what the prior equipment delivered.

Unfortunately, the complicated high end stuff needs to be installed and set up properly, or else it won't work.

Even if the refrigerant charge is off, it will not work right (or, if they burned the TXV during installation).

The size of the company doesn't matter when compared to installation performance.

HVAC manufacturer "Premier Dealer" or "Comfort Specialist" labeling/branding is tied to sales (number of boxes moved), not quality.

I would seriously start by reading through the setup instructions in the factory supplied kneepads (the installation instructions), and at least look at how it is set up.

 

[Jackfre]

I would register my complaint further with the company. Just by them saying that the old units were better shows that they are not properly trained on the new gear. Say that is the way they work shows that they do not "know" how they work and so they are likely not set up properly. Don't start screwing around with it. That give the contractor an out on warranty issues. Actually, as I think of it a part of the installation should have been through training of your brother on how to deal with the system and its menus and options.
I would take the issue to the owner of the contracting company. If they do not satisfy you, you then contact the Trane Distributor in your area. They will have a tech guy who likely gains the contractors and backs them up when things hit the fan...as they are about to. Failure by them takes your brother directly to Trane. Don't settle! Hell, all you want is your moneys worth.
Oh, and one other thing to keep in mind. The problem could very likely be at least partially, the old duct work.Not saying for sure that it is, but not all of the variable speed stuff works well on an older systems design.

 

[Dumber than lumber]

We have a Trane variable speed. Only have the single unit for the entire house. Works great. We have had it for 12 years.
Like the other members are saying - contact Trane. If the old units did the job better how could new units be installed correctly?
Alternatively - your bro could hire an AC engineer to look at the entire install. I might tell the installer that i was looking at that route and they would have to pay for any defects found with the install, and the cost of finding the defects.

 

[Ohmthis]

The XV18 is a variable compressor unit. The XR17’s are two stage heat pumps. My bet is that the XR17’s are running on low stage only. Say the total output is 36k btu or 3 tons each. But when in low stage the output may only be 15k btu or a little over a ton. If the manual J (load calculation for how much heat gain/loss) shows 36k btu are required, but only 15k btu are being supplied, I can easily see where there would be a problem. Tommy is right, capacity is capacity. I don’t believe you are reaching it. Installers and techs are different, and that is not to knock on anyone. A wiring/setup looksie is in order.

 

[danski0224]

I hate to say it, but time to get an attorney involved, their attitude is unacceptable. If you want to play the social-media game, don't exaggerate, don't lie, but companies really don't want the bad P.R. on facebook or wherever.

I'd push it up the Trane food chain before doing any of this.

 

[TangoFoxTrot]

Thanks for the feedback, I'm just going to tell him to call Trane and see what they can do to make it right. I don't think he should really poke around on his own with any of it.

Its his problem, just didn't like that he was being lied to about why it's not performing. I just want him to rectify it in a reasonable amount of time after install so they can make it right on their dime and not his.

 

[jeepxj]

yea thats a load of ****. its peak season heatwave time in most of the country. they dont want non money making AC out calls to go un-answered trying to warranty that stuff.

 

[driftpin]

I agree something isn't right. We have a Lennox MC25-060 variable speed, and it works fine, it cools well, no-need to 'overshoot' to get it to cool properly. 3,000 sq ft CBS construction home.

I hate to say it, but time to get an attorney involved, their attitude is unacceptable. If you want to play the social-media game, don't exaggerate, don't lie, but companies really don't want the bad P.R. on facebook or wherever.

I'd push it up the Trane food chain before doing any of this.

Yes, I agree, I was just looking at it from the "$28,000 viewpoint." Spend that kind-of $ and you expect a better-performing system, cheaper electric bills, and no "your old system was better" from an installer.

I will-say that in my opinion, a certified letter from an attorney to the registered business agent of the HVAC corporation which did the work is definitely going to get someone contacting the homeowner immediately. A c.c. to the Trane distributor or to the corporate HQ, perhaps both, is going to get the ball rolling, quickly.

This O.P. is another example of not-knowing where the O.P. is, or the brother he's discussing, is, and not good for readers being able to provide feedback. A location below your screen name is all it takes. An example, my friend is 40+ years in the business a master license holder, he's in the W. Palm Beach FL area and if that's where the brother of the O.P. is, my friend is probably on a first-name basis with both the Trane distributor and the regional factory rep.

 

[BD1]

Sounds like units are undersized.
As others stated, contact Trane.
Is the installer a qualified Trane installer??


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[yeldogt]

The VS equipment has no problems -- they have the same outputs on highest setting.

Something is not correct .... find out what he had and what's installed. loads done and ductwork checked?

The controls have to be correct and set up properly -- the systems use specific thermostats

 

[nadogail]

Sounds like there is something rotten in Denmark.

 

[dcg9381]

I'd push it up the Trane food chain before doing any of this.

Or see if building code addresses HVAC performance.

I agree with others - if the units can cool the structure down via "overshoot" then something else is wrong. The cooling capacity is there.