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Old 09-29-2010, 10:24 PM   #16
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low pressure at vents


anyone have any ideas? thank you in advance, any help is very appreciated

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Old 09-30-2010, 04:05 AM   #17
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low pressure at vents


dang, tonight came and went.

Forgot about this thread Tuesday.

Good news, is since the furnace is in the middle of the house, you won't need to go to 32X8 duct.

Bad news is I don't have time this morning to go over the drawing. But I will tonight.
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Old 09-30-2010, 08:45 PM   #18
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The side with 17 supplies, would work better if it was 24X8.

You probably don't have enough return to give your supply much air flow.

You may want to add a floor register return somewhere on the first floor. In an out of the way area.

As a test. Remove the blower return panel. Hold in the blower safety switch and have someone turn the thermostat to fan on, and check the air flow from the registers. then do the same test with the panel on. And see if its a lot less air. if so, add more return.
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Old 09-30-2010, 08:53 PM   #19
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low pressure at vents


I am going to have to remove the return air duct anyway to install a bigger supply duct, so whatever size I need for supply and return is what I will put up. thank you again!!
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Old 09-30-2010, 08:56 PM   #20
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I was told in order to have a balanced system you should have as much return as you do for supply. Is that correct?
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Old 10-01-2010, 01:40 AM   #21
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You said to use 24x8 duct for the one side, what size duct would you use for the other side? thanks alot
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Old 10-01-2010, 04:31 AM   #22
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Originally Posted by toohott7718 View Post
You said to use 24x8 duct for the one side, what size duct would you use for the other side? thanks alot
The other side should be ok. It has fewer supplies off of it.

Balanced return and supply is a misleading statement.

The return duct generally works better being a larger size then the supply. That allows for the air filter to get dirty.

I would go 1 size larger on the return duct then what the supply is. And add a return like I said(the test will tell you if you need to add a return of not).

The actual location of returns has little bearing on the performance of the system. If you have good air throw from the supplies.
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Old 10-02-2010, 03:34 PM   #23
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you said I should use a 24x8 on the side with more vents would work better. would it be wise to go up to a 26x8 instead? thanks again for all your help
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Old 10-02-2010, 03:47 PM   #24
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If you do. You may nee to install dampers in those supplies. As it will effect the other side.
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Old 10-02-2010, 04:38 PM   #25
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ok I just wanted to make sure Im going to be doing alot of work and I just want everything to be right. so 24x8 on the side with more vents and keep my existing 20x8 for the other side correct? and as far as the return maybe a 26x8 on the side with more vents, and leave the existing return on the side with less vents. thanks again
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Old 10-02-2010, 05:17 PM   #26
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The sizing you posted is good.

You will most likely have to add returns tot eh house also though. Doubtfull you have enough.
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Old 10-02-2010, 06:09 PM   #27
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I planned on adding a return on the side with less vents, as far as the other side almost every room has a return that has a supply vent.
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Old 10-02-2010, 06:40 PM   #28
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Is the side with less vents open to the other common areas?

Most of the time. When you count the number of returns to supplies. Even if the return number is the same as the number of supplies. The returns are using more restrictive grilles then the supplies. And you end up needing more returns.

Returns that use wall cavities are very restrictive.
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Old 10-02-2010, 07:14 PM   #29
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the side with less vents is areas such as the laundry room, the kitchen, the living room and the dining room. I plan on adding a return in the dining room and in the laundry room. you said the return should be bigger than the supply, so should my return line be a 26x8? thanks alot everyone

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Old 10-03-2010, 01:55 AM   #30
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Don't put a return in the laundry room. Lint is not a good thing for your central system.

How many returns are on that side?

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