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Old 08-24-2013, 07:23 AM   #31
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Return Air in the basement


Beenthere,

I put my hygrometer in the corner of the basement overnight. It was on the floor and it registers 88%, which I believe is pegged.

Mine is a sheit basement with no waterproofing, backplastering, or insulation on the exterior. You can bet that there is no vapor barrier under the concrete.

However, by running the furnace fan continuously, I do keep it from getting moldy down there.

I'm used to a poured wall with waterproofing and 2" xps on the exterior and a vapor barrier under the floor. That, in my opinion, produces a much more useable basement.

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Old 08-24-2013, 07:59 AM   #32
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Return Air in the basement


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Beenthere,

I put my hygrometer in the corner of the basement overnight. It was on the floor and it registers 88%, which I believe is pegged.

Mine is a sheit basement with no waterproofing, backplastering, or insulation on the exterior. You can bet that there is no vapor barrier under the concrete.

However, by running the furnace fan continuously, I do keep it from getting moldy down there.

I'm used to a poured wall with waterproofing and 2" xps on the exterior and a vapor barrier under the floor. That, in my opinion, produces a much more useable basement.

Get 2 disposable plastic containers. Get a slice of bread and tear it in half, and put a half in each container. Then put 1 container in the middle of your basement where you were reading 55 to 60% RH, the other at that corner.

See if the corner develops visible mold in less then 12 hours before the one in the center. If so, you probably have mold you can't see in the basement.
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Old 08-24-2013, 08:00 AM   #33
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Return Air in the basement


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The contractor was rushing through my house and I am concerned that he may not do the correct calculation. It is a 4-ton system. The return is the size of the filter, which is 20 by 25. Please see the picture below. What should be the correct duct size and size of return register? Thanks a lot!
That return set up is one of the worse you can have.
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Old 08-24-2013, 08:21 AM   #34
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Return Air in the basement


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A 16X24 floor register would work
Should return ducts also be 16X24? Thanks a lot!
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Old 08-24-2013, 08:26 AM   #35
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Should return ducts also be 16X24? Thanks a lot!
A 12X24, or 10X28 duct is ok. The grille is larger, as it is not just an open hole. It has slants that take up space, and reduce the total amount of free area for the air to travel through.
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Old 08-24-2013, 10:44 AM   #36
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Return Air in the basement


Beenthere,

I am following your directions precisely.

I almost used a glass container and a plastic one, but luckily there were two identical plastic containers available.

I cut the slice of bread on the diagonal and I have them sticking up out of the corners of the containers.

My helper, Igor, approves of the experiment.

When do we get to the part where we put the brain labelled A.B. Normal into the cadaver and jump start it?
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Old 08-24-2013, 10:47 AM   #37
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When do we get to the part where we put the brain labelled A.B. Normal into the cadaver and jump start it?
2 hours before the thunderstorm starts. LOL
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Old 08-24-2013, 02:28 PM   #38
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Return Air in the basement


My goodness. I just found out the window in my basement utility room was completely covered by dusts and dead tree leaves from the outside. There was no air intake through the window to the utility room at all. The previous owners are nuts. This is why I find that air was rushing into the basement staircase when the central AC is on.

I will clean up the basement window and open it slightly since it is dry and not too hot outside.

Should I close the basement window during hot and humid days?
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Old 08-24-2013, 02:31 PM   #39
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My goodness. I just found out the window in my basement utility room was completely covered by dusts and dead tree leaves from the outside. There was no air intake through the window to the utility room at all. The previous owners are nuts. This is why I find that air was rushing into the basement staircase when the central AC is on.

I will clean up the basement window and open it slightly since it is dry and not too hot outside.

Should I close the basement window during hot and humid days?
Where is the combustion air going to come from on those days.

Air will still rush to the basement from the first floor, as long as the return is open in the basement, and not connected directly to the first floor.
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Old 08-24-2013, 02:35 PM   #40
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Where is the combustion air going to come from on those days.

Air will still rush to the basement from the first floor, as long as the return is open in the basement, and not connected directly to the first floor.
So you suggest me always open the window slightly for the combustion air, no matter whether it is summer or winter?
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Old 08-24-2013, 02:46 PM   #41
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Return Air in the basement


Seal the utility room from the rest of the house and run a direct return to the first floor. Then provide a direct air in take for combustion to that room.

Yes, for not leave the window open. No way to tell if you have been back drafting the water heater or not from my side of the internet.

However, you can test it. Use a match while the A/C is running, and hold it near the dilution hood of the water heater, and see if the flame is drawn into the hood, or pushed a way. Try it with the water heater not burning, and then with it burning.
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Old 08-24-2013, 02:54 PM   #42
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Return Air in the basement


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Seal the utility room from the rest of the house and run a direct return to the first floor. Then provide a direct air in take for combustion to that room.

Yes, for not leave the window open. No way to tell if you have been back drafting the water heater or not from my side of the internet.

However, you can test it. Use a match while the A/C is running, and hold it near the dilution hood of the water heater, and see if the flame is drawn into the hood, or pushed a way. Try it with the water heater not burning, and then with it burning.
If I open the window very slightly, does it serve the purpose of direct air in take for combustion?

The return will be on the 1st floor on Monday. Oh, Yeah! Do I need a small return in the basement to keep ventilating the basement? I have two supply vents in the basement.

Thanks so much...
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Old 08-24-2013, 03:00 PM   #43
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If I open the window very slightly, does it serve the purpose of direct air in take for combustion?

It can. But people tend to close it in the winter. So a true combustion air intake should be ran to the sealed utility room.

The return will be on the 1st floor on Monday. Oh, Yeah! Do I need a small return in the basement to keep ventilating the basement? I have two supply vents in the basement.

Thanks so much...
After the utility room is sealed from the rest of the basement. A small return is ok.

Unless your trying to keep the basement at the same temp as the first floor. Should only need one small supply.

Remember, its the humidity that will give you the musty smell.
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Old 08-24-2013, 03:04 PM   #44
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After the utility room is sealed from the rest of the basement. A small return is ok.

Unless your trying to keep the basement at the same temp as the first floor. Should only need one small supply.

Remember, its the humidity that will give you the musty smell.
Thank you! I will run a dehumidifier non-stop. This is why I am wondering whether a small return in the basement is necessary.
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Old 08-24-2013, 03:11 PM   #45
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Thank you! I will run a dehumidifier non-stop. This is why I am wondering whether a small return in the basement is necessary.
A return is only needed, if you have a supply in the basement.

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