New HVAC house not cooling/warping wood inside/ducts sweating bad

[revin]

Well Hello

I'm Kevin and I live in S/W Missouri. House is a 1985 1.5 story aprox 1750sf, and has not so good windows, and no vapor sheeting, and not too good batten insulation. 2 B/R up with 1 full bath[300sf+/-], so only 3 vents up there, all under a 44square roof.

I'm a Cosmetic Engineer and have to deal with with +/- .002 by HAND with air grinders ect in my job, and love to build Pontiac engines! Been doing both for 30 yrs. TBH i'm a big Mike Holmes fan["Glue it and screw it!, Do it right ALWAYS!], so mabey you can understand why I may be just too picky.

To start off the old furnance blew the exchanger, so we decided to see about a total system since it was 20+ yrs. old.

First contact kept fumbling about when I kept inquiring about callbacks[about 10%] failures ect, and then about which brand's and that made me uneasy. Come to learn he'd stated he;'d only been doing it for about 5 yrs.

Second tech [recomended from a friend [w+/- 30 yrs exp.] came out, was easy to awnser my questions, and indead was a nice guy, but more imporntant to me was he'd listen and give me straight awnsers.

He did a quick lookover and looked over some chart [similar to a slide rule?], then after about 15 min gave us a sheet with 4 price sets.

After the sticker shock we explained that we had x amount to spend, which was just under his lowest price.

The old unit was a 3.5 ton Arcoair and so we inquired about staying with same size[3of4 prices were 3.5] We made it clear that the old unit would litterly run 20 hrs a day from May thru Oct.

He advised that the "new" units were far more efficiant, and that it should be fine. We asked at least 4 times about using a 4 ton setup, and I did voice my concern about having a high "heatload" home.[Always hot up, and cold down] But in fairness the chart's I seen on the WWW show that a 3-3.5 ton is recomended for this "location"

So after all the installing, we indeed seen an increase in airflow, but first issue was that it wasn't getting very cool inside, the ducts under the house were sweating real bad and was still running about 15 hrs. day, even on an 80*OT.[Therm set to 73*

He reduced the blower to medium. I called him 3 hrs later, and told him that the vents were sweating and the house was getting hotter, so he came back over that nite and went back to high. He was having the new plenium made for the air intake for the handler, so after getting installed it helped airflow alot, but things really got bad after that.

We had a couple days that got to 92 O/T and the unit didnt go off for almost 30 hrs!, twice that week it happended!
thing is that in the beginning we first noticed that an extiorer door started sticking, but now after the 2 events, our fireplace mantle has warped[about 1 in] and is pulling apart from itself!!

I have been informed from a couple sorces that it's pulling all the moisture out of the inside of the house. Turns out that some of my flex duct under is loading up with water also!

After talking with the Mfg, we were advised to get a second opionon, but they[mfg/3rd tech] felt that the unit was really undersized.

We called him yesterday and advised him that we "want a 4 ton unit put in, that we need to nip this now before it gets too hot"!

So are we on the right track to get a 4 ton unit?
Thanks for any input.

[RoBoTeq]

Unless a system runs 24/7 and does not satisfy the thermostat setting, it is not undersized. Longer run cycles from properly sized systems is the most efficient way to operate a system and will provide the longest life for a system. The life of a system is less reliant on overall run time then it is on how many cycles it has run. The worst thing we can do to any motor is to start it.

Putting in a larger system will cause noisier air flow as well as maybe your existing ducting not even being able to handle the additional capacity. Your electrical system may also not be proper for a larger system.

[dj3901783]

First off what did they put in... model numbers... and a good thing to check is if the T-stat is set at 73 then check the temperature on the return air duct, then check the temperature at a few of the supplies...

[beenthere]

I would get a hygrotherm and double check your indoor humidity.
Warping can also come from not removing enough humidity.

[revin]

That dont make too much sence to me TBH.
It's not cooling the house even running for 2 day's!
Ducts filling with water?!!
Wood warping?!!
It shouldn't be worse off with a "new" modern system.
I'd rather put the old AC back in, even if it did use more enegry.

The house is just uncomftouble like it's dryed out or something, and not to mention ther's a concern about molding now that all the ducts a soaking wet!

[revin]

Actually the vents had 55* coming out, but again it was only 78*.

Never had any "wood" issue before, but the first thing they told me was that a unit running contious like that is a sign of undersized.

[markwolf]

With all the moisture I would suspect some duct leakage.
It sounds like you are not moving enough moisture out.
your sticking door is swelling I highly doubt the jamb is shrinking around the door!
Where is the return run?

[beenthere]

The water in the ducts is usually caused by high velocity. Indicates undersized ducts.

The museum I take care of, has to be very carefull with their humidity in both summer and winter.
The inlays get loose if its too dry, and the wood pushes apart with too much humidity.
Some of their displays of Grandfather clocks, and 200 year old chests, and hutches are in excess of $100,000.00. So they are picky about their humidity.

[revin]

The drain tube is flowing bigtime, far more that the old unit.
I keep having to take a rubber mallet to hit the jamb back to keep the door from hitting.

Return is across from the T-stat at the floor in the hall that has the stairwell.
It's a 16 feed to the plenium thats 21x21x25 deep.

As for the runs, there 18x8 2 of them, 1 has 5 6" takeoffs and the other has 7.

[revin]

The water in the ducts is usually caused by high velocity. Indicates undersized ducts.

This water buildup that I found is over 30 ft from the unit by the end of a run.

[revin]

With all the moisture I would suspect some duct leakage.
It sounds like you are not moving enough moisture out.

ie. an undersized unit??????

[revin]

Putting in a larger system will cause noisier air flow

It's already running the fan maxed out at 2000cfm, so not too worried about noise.

[beenthere]

More like your pulling fresh air into the return. Then undersized.
Undersized tends to remove more humidity, but not cool the house as well. Oversized tends to cool the house too quickly, and not remove humidity.

Your duct system isn't sized big enough for a 4 ton unit.

Look for areas that the return is drawing in air from the crawlspace. That would cause you to see a lot of water coming out of the drain.