Correct AC Unit?

[pa ssc]

I recently had a new air condition unit installed in my house. It does not appear to be working properly although the company that installed it says it is. Below are the problems I am having and the specs on the house/AC. Any comments would be appriciated.

House is 2600 sq/ft.
Original furnace (Installed 1976)is a Westinghouse Mod#foud154rd, Series 1kue, it has a single speed fan.
Original AC (Installed 1976)was a 4 ton unit. Its gone now so thats all I have on it.

New AC unit is an Armstrong 4 Ton, 12 Seer.

I keep the thermostat set on 72. When outside temp gets above 90, inside temp goes up. At 95 outside, 79 inside.

When the humidity outside is above 45% the inside humidity is 50% or higher. As the outside humidity goes up, so does the inside. We have condensation on our doors/windows at times and never had this happen before the new unit.

The duct work sweets to the point that its ruining the cieling tiles in the basement.

The unit once took six hours to drop the temp from 80 to 78. This was from 4:30pm to 10:30 pm, not during the heat of the day.

The old unit never caused any of these problems, kept the house at whatever temp I set it on no matter what the outside temp was.

Any thoughts.

[t527ed]

duct work sweating thru ceiling points towards airflow problems.

[BaldLoonie]

Exactly. That old clunker furnace probably isn't moving 4 tons of air so the ducts get very cold. Why it's different now may be that the unit is working better and getting the air colder.

Where's the window sweat? In or out? If on the outside of the windows, that isn't the unit's fault. We've had a very steamy summer and lots of home windows fog up outside as the cold air inside causes the window glass to drop below the dewpoint.

[pa ssc]

Windows sweet on the inside.

[udarrell]

Maybe you should have kept the old 4-ton unit, --sounds a though it performed many times better than the new one.

There are obviously some major things wrong with the new unit.

Maybe the installers need some new technology test instrument trouble shooting help? It may be expensive, --but provides examples of the test points to use. I do NOT sell test instruments, or have any connections whatever to any test instrument company!

http://www.cee1.org/cee/mtg/9-04_ppt/sundberg.pdf

http://www.udarrell.com/air-conditioning-efficiency-btuhr-evaporator-coil.html

[smokin68]

Have your ductwork checked.....size and condition. This should have been done before installing new unit.......was a load calc done? Things change in 30 years.