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Installing a damper on a 10 year old A/C....

mpire

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Nov 21, 2008
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1,856
Location
Florida
So I am going to have this mini-split up and operational next week sometime I suspect, and that will do the job of cooling off the master bedroom, which is literally the only room upstairs that isn't storage.

I was thinking of installing something like this:

6inchDamperNormallyOpenRegular.jpg


The master bedroom has one 8" flex duct.

The master bathroom/closet has three 6" flex ducts. (toilet closet, master closet, and middle of bathroom)

The top of the stairs/hallway/foyer has one 8" flex duct.

The two bedrooms have 6" flex ducts.

Guest bath upstairs has 6" flex duct.

The goal would be to basically eliminate all the a/c upstairs other than the hallway which is open to the downstairs foyer.

And maybe leave the master bathroom, but I am hoping that the master bathroom will get some cooling from the mini-split that is 6 feet away in the master bedroom.

So if I can put a damper on the guest bedrooms, and move the thermostat downstairs, I think I would get more efficiency out of my existing a/c system by essentially making it a downstairs only unit.

This would leave the downstairs cooling to the 10 year old system that is at best 10 seer. I think its a 4 ton system. It cools the downstairs just fine, but the upstairs not so well. Basically if you want it cool upstairs, the downstairs is cold. Doesn't seem all the efficient to me, probably because all the cool air runs down the stairs and fogs up all the downstairs windows.

The downstairs has:

Two 8" ducts in the living room (18 foot ceilings)
Two 8" ducts in the dining room, but now they are split in half by a wall, so one in my office and one in the dining room. (10' ceilings)
Two 6" ducts in the kitchen/breakfast nook. (10' ceilings)
Guest half bath has 6" flex duct.
Laundry has 6" flex duct.

So with the thermostat downstairs, I am hoping it will be more efficient and do a better job keeping the downstairs cool and not COLD. Downstairs is approximately 1200 square feet. Single pane windows with concrete block walls. I do have a triple pane window in my office with the low-E coating, so that helps.

So I guess the question for the A/C gurus comes down to blocking off the ducting for the upstairs. I don't need the duct in the master bedroom anymore, and I don't use the rest of the upstairs at all. Literally. Christmas decorations and car parts are the only things up there. I want to make sure I won't be hurting or over stressing the 10 year old carrier 38YCC048300.

My neighbors compressor blew up last week. They just dropped 6 grand on a new system. I don't know their service history, but I have mine serviced every 3 months or so. I have replaced all the capacitors and the contactor in the last 3 years. You can get your capacitors for $5 online, no kidding, from the a/c contractor they are $200. I am not making that up. Thats why I have new spares just in case. Oh, and when the neighbors unit blew up, I stripped off all the electrical parts to have as spares from the indoor and outdoor units. So I am ready if any of the electrical boards or capacitors burn out.

Thanks in advance!:thumbup:
 
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rickairmedic

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May 31, 2005
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Location
louisville ,Ky
Mpire my advise would be to simply close the vents in the rooms you are not using and not completely shut down that part of the house . Your system was most likely designed to cool your whole house and by closing off half of the system you will be putting stress on the system . You do have a 4 ton carrier system . Where is the air handler unit in relation to upstairs . I know from experiance most of the homes down there that are around 10 years old the air handler is in the garage and usually on the other end of the house from the bedrooms :D. The master you could close off completely due to the new mini split but in the other rooms you are not using I would only close the vents 3/4 of the way as you still want some airflow and circulation in those rooms .


Oh yeah not " all " contractors charge $200.00 for a capacitor and there are capacitors that cost us more than $5.00 " multitaps " for instance cost more than $5.00 :D. I will admit though most of the 60 minutes specials on HVAC contractors have been filmed in Fla:D not to say that all HVAC contractors in Fla are bad but the good ones do seem to be outweighed by the bad.

Rick
 
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mpire

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Nov 21, 2008
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Location
Florida
Well, let me clarify...

MY capacitors cost me 5 bucks online. Roughly, or at least the ones I got from the a/c people. They have to pay for storage and inventory, so I don't really mind it so much. I just bought extras just in case they blow again. It gets hot here in Orlando.

The a/c unit is actually right in the center of the house upstairs. The thermostat is on the same wall as the unit. The cable to the thermostat is about 2 feet long. Thats why I am thinking it would be a good idea to move the thermostat down stairs so it gets better readings and cools the downstairs more accurately. My house is literally a box with block on the bottom story and sticks on the top. The ducting runs through the attic and then down to the rest of the house.

I never open the doors in the extra bedrooms upstairs because I don't want the wifes cat getting in to them. So the doors stay closed and we never go in there. I don't see the point of air conditioning them.

Cant close the vents off because that causes water to condense on the vents. So looking at a way to just close off the duct work instead.
 
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mpire

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Nov 21, 2008
Messages
1,856
Location
Florida
Ok, so this has evolved a bit.

Do they make a diverter valve for a/c ducting?

So I can divert the from one pipe to another.

diverter-manual.jpg
 
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