Is my builder shafting me with the AC unit he selected?

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Hi
I bought a new house from one of these bulk builders. THe house is a two story house with two separate A/C units. I have been having some trouble in the summer here in Florida with the unit upstairs. While it cools adequetely, it seems to stay on all the time. Ie it does not cycle on or off like a normal A/C when it is set at any temperature below 77 degrees. The fact that it stays on continuously concerns me as I suspect that this will ultimately affect its useful life.
In either case after bringing out the A/C company three times they think it is quite normal and ok considering it is the summer and we are in Florida.
Not being satisfied, I went down the street and noted that the A/C units that were used in an exact house like mine from the same builder were a bit bigger and more efficient. Now the house was more recently built so I think that may explain why they have more efficient units especially with the EPA continuously increasing the standard. HOwever I am curious to know why they installed a larger unit in the other house.
My question is whether the differences in the unit are large enough to warrant further inquiry or if the differences are trivial. I am just a lay man so I dont know what is a significant btu/h difference. In either case, I have a regular unit and a heat pump unit whereas the house I am comparing had two heat pump units.
Here are the specs of the two units in my house:
Lennox - 10ACC-036 10.9 Seers Cooling - 27,600 - 29,000 btu/h
Lennox - 10HPB30 10.5 Seers HSPF IV 6.95 / V - 5.95 Cooling 28,000 - 29,800 btu/h Heating 25,400 - 26,000 btu/h
The house I compared had two heat pump units that were the same size. The spec of them were as follows:
Lennox - 12HPB30 (x 2) 12 Seers HSPF IV 8.2 / V - 7.25 Cooling 28,400 - 31,000 btu/h Heating 29,600 - 30,400 btu/h
So the question is whether the differences in cooling and heating between my units and the units on the comparison house are significant enough to explain the problem I am facing.
Any other comments appreciated.
Thanks
jasguild
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jas kim wrote:

Being on all the time, as long as it does cool properly is not a defect and it means you should be getting very good humidity control, which you would not get if it were oversized.
It is difficult to say if it really is too large or small without an on site look.
When you are looking at the "larger" unit down the street is it physically larger? It is only 0.6% more capacity, which is nothing. The physically larger part has more to do with the higher SEER than the increased capacity.
--
Joseph E. Meehan

26 + 6 = 1 It's Irish Math
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The slightly larger size should not make a huge difference. The upstairs unit will run longer as there is a greater heat load from the sun on the roof.
Running longer will also dehumidify better. Thee is such a thing as having too large of a unit. To determine if yours is correct, you'd have to run a Manual J check to determine the load. The builder may have the information you need.
You can also ask for information an alt.hvac ;)
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Edwin Pawlowski wrote:

Have the manual J done, or reevaluate it if already done!
There could be several factors causing the system to not be transferring its rated BTUH of heat to the outside!
<A HREF="http://www.udarrell.com/my_pages2.htm#MY_AIR_CONDITIONING_PAGES ">
If you do some homework studying you may find some things that are not up to snuff! Print and give to your A/C tech. He will probably say it is trash, ha.
First, check the temperature rise off the condenser, and let us know what the readings are!
udarrell Darrell
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Or you could STFU and let those from that group respond here in the appropriate forum rather than send this person to the wrong NG.
- Robert
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There's nothing wrong with asking hvac questions in hvac groups.
Here's one for you:

How about a little greenhouse? Hang a piece of plastic over an EW line between two poles, then string another line below it. Leave the ends of the tent mostly open.
How open? If they are completely closed, the water vapor never escapes. If they are completely open, the greenhouse adds nothing, compared to a clothesline.
Nick
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Except in the minds of the arrogant lots who wrongly claim otherwise :-)


Who says? :-)
You are also invited to answer this hvac science and engineering question. Be sure to compare the drying rate to an outdoor clothesline and include the effects of condensation, if anticipated.
Nick
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snipped-for-privacy@ece.villanova.edu wrote:

Fucktard.
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Don Ocean and and PJM are also invited to answer this hvac science and engineering question. Please compare the drying rate to an outdoor clothesline and include the effects of condensation, if anticipated.
For the sake of definiteness, if Greg wants to remove 12 pounds of water from 12 pounds of clothes with 400 ft^2 of surface (both sides) in minimal time in full sun in August in Key Largo, when it's 84 F and w = 0.0185, using a 16'x16' R1 greenhouse with 90% solar transmission, how many cfm of outdoor air should flow through the greenhouse?
Nick
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snipped-for-privacy@ece.villanova.edu wrote:

This is for you to answer Nick. Just what makes you think sci.engr.heat-vent-ac is interested or the appropriate place to discuss clothes drying?
Your mother drop you on your head or are you so desparate for attention you have to post shit?
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It's a matter of basic HVAC science and engineering. Chapter 28 of the ASHRAE Applications handbook is all about drying, drying times, and so on. The SCI.ENGR.heat-vent-ac group should eagerly welcome such basic questions.
What are your answers?
Nick
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snipped-for-privacy@ece.villanova.edu wrote:

Funny. There isn't a single mention of clothes or dryer in the 2000 version. And as far as I can tell. Except for venting of a clothes dryer, there is absolutely nothing on "drying, drying times, and so on" of clothes in ASHRAE books anywhere.
Care to explain that?
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Where ELSE would we discuss this question? :-)

My 1991 Applications book has drying hygrometry and drying time calcs on pages 28.1 and 28.2...

Chapter 28 applies to all kinds of drying, as we can see from some of the references, eg
Bell, J. R., and P. Grosberg. 1962. The movement of vapor and moisture during the falling rate period of drying of thick textile materials. Journal of the Textile Institute, Transactions 53(5):T250; ABIPC 33: 72, and
Nissan, AH. 1968. Drying of sheet materials. Textile Research Journal 38:447.
Now then, got any answers?
Nick
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snipped-for-privacy@ece.villanova.edu wrote:

Alt.clothes, alt.clothing for starters. They probably already know what it takes. However as anal as you are you want to continue to reinvent the wheel. I suspect since you didn't really understand it the first time.

Clothes drying references? Where are they? Lying isn't nice. I concede it is a liberal thing to do though. Try using references within the last ten years ok? Technology changes. We don't discuss Sulphur Dioxide here much either.
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I disagree. What do they know of I. S. Bowen's 1926 equation?


See above, at the end of Chapter 28. Perhaps it's time to stop your silly gatekeeper games and answer the question, if you can. If not, your silence will suffice.
If Greg wants to remove 12 pounds of water from 12 pounds of clothes with 400 ft^2 of surface (both sides) in minimal time in full sun in August in Key Largo, when it's 84 F and w = 0.0185, using a 16'x16' R1 greenhouse with 90% solar transmission, how many cfm of outdoor air need flow through the greenhouse? With no ventilation, the water vapor never escapes. Too much, and the greenhouse adds nothing, compared to a clothesline.
Please compare the drying rate to an outdoor clothesline and include the effects of condensation, if anticipated.
Nick
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wrote

Why? I've met a few guys from that group and they are a rather sociable bunch.
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wrote in message | > While | > it cools adequetely, it seems to stay on all the time. Ie it does not | > cycle on or off like a normal A/C when it is set at any temperature | > below 77 degrees. <snip> | | You can also ask for information an alt.hvac ;) | Best put on your asbestos suit before posting any questions to alt.hvac being just a mere mortal.
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wrote in message

Why? Oh..thats right....alt.hvac is not for homeowners, and thats why many of us post here too..
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wrote:

Now how would your average newsgroup reader know this?
Alt.hvac seems like the place to ask about hvac stuff, until they get flamed for asking a reasonable question,
email to snipped-for-privacy@notreal-ruybal.com (remove the "notreal-")
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If the hvac guys wanted to keep the group on a professional level, they should call the newsgroup alt.hvac.professional Instead, a few of the members take delight in flaming anyone from outside that asks a question, even it if is hvac related. Unless the group is moderated, I don't see how they can prevent others reading/posting to the group.
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