the A/C guy came yesterday...

[sdeemer]

more from houston. i have been posting messages about our new A/C unit 4-ton not cooling the house well. especially downstairs aafter 3pm. inside temp 76 outside 95F 95% humidity. 2850 ft2 i think the unit is not large enough.

some of you recommended i have someone do a manual load calc (or do my own via the link) which i plan on doing. but i am trying to see what the builder is going to do. everything in our house is basically under warrenty for 1 year i believe.

yesterday the A/C guy made the 5th trip over. this time no to rebalance but to check out thi system operation, etc etc. this is the people contracted by our builder, mind you. he said everything checked out except one thing.

our system is "zoned" with 1 unit but dampers that control upstqairs/ downstairs. he said that the location of the "unit" in the attic was the problem. that the upstairs "unit" was placed fine hence the upstairs was cooling. but the downstairs unit in the attic was placed wrong and in a bad location to provide cooling to the downstairs.

now does this make any sense to anyone? he drew a diagram of the unit and was going to take it back to his sup and then i guess make changes in the attic. any A/C guys let me know what you think. i live in houston. thanks

[danglerb]

I'd say let them do their job and judge them on the results.

In my idle time waiting for phone calls to be returned today I read all of the front and back of the bid form I got from my contractor. Item 1 on the back says, "In conventional two story homes, temperature variations between first and second floor are normal." more yada yada, then says I have 5 days to make any shortage or defect know to the contractor.

I think I prefer fine print to the light grey on the back.

[dan sw fl]

Originally posted by sdeemer
more from houston. i have been posting messages about our new A/C unit 4-ton not cooling the house well. especially downstairs aafter 3pm. inside temp 76 outside 95F 95% humidity. 2850 ft2 i think the unit is not large enough.

yesterday the A/C guy made the 5th trip over. this time no to rebalance but to check out thi system operation, etc etc. this is the people contracted by our builder, mind you. he said everything checked out except one thing.

Now does this make any sense to anyone? he drew a diagram of the unit and was going to take it back to his sup and then i guess make changes in the attic.

Obviously an air distribution problem !

READING and Maintaining a thread (instead of double posting) frequently helps solve one's concern.
.................................................

Do you think that the > 5th time
the mechanical contractor visited he would be any luckier in enhancing the performance?

Air balancer fee for half-day service
might be in the $250 range.
However, do NOT expect your builder to actually
address your concern until REALLY FORCED
with presentation of independent report and
setting of date for a court appearance.

Let me guess ...
Air handler is in the attic.
------------------ Upstairs ___ Downstairs
Supply Air Temp ...._______ ....________
Return Air Temp ...._______ ....________

Supply air duct chase is __"x___" and located ___
Return air duct chase is __"x___" and locaetd ___

The downstairs ducts need to handle
> 800 CFM (> 1.1 square feet of metal duct or minimum 14" flex duct with 16" diameter actually preferred).

Send plans, window sizes/specs and
house orientation for full evaluation and
comparison of calculated air flow rates per room
to the air balance test report.

Electric usage per day = ?
___ 80 kw-Hr
_X_ 70 kW-Hr
___ 60 kW-Hr
___ 50 kw-Hr

2,845 Sq. Ft house in Houston with a 4-ton might be sufficient if you have < 11 tinted windows
AND no sliding glass doors
or 15 windows if None of the windows face East or West.
(hvac hero says it is 'way undersized' ...
but I need to deal with actual facts prior
to providing a more realistic evaluation)

How do I know the approx. A/C unit size required?
I have performed probably
> 400 Manual J calcs in the last few years.