tom m

Im looking for any input or suggestions from the HVAC guys. I have to either cap off or arrange a new floor diffuser. Heres's the situation: I have an existing 7" round flex duct brought up through a 1st floor closet to a second floor wall. We added a bathroom addition on the second floor and I now have a door where the supply was. I have no walls to utilize this supply. I dont know if I can use a floor register in a bath or not but I have a 6 inch round to 3x10 straight elbow in the garage, I thought it was what I needed but its not 7" so should I reduce it? Do they even make a similar set-up for 7"? Any advice would be appreciated.

tom m

Not much action here............Turns out they do make it in a 7". Monday is the lastest chance I have to do something different. I have come to another conclusion I hope will be correct. After all this I am going to cap it off. I traced it down and it is a return. It was meant to balance the system or help circulate air on the second floor. Since it was in a hall and the adjoining bedrooms were carpeted, there was no under cut at the doors. I figuired it became usless with the doors closed. I am installing a 100cfm fan in the bathroom that will operate every time the light is on. Any other ideas I am open to.

Aceinstaller

be careful,there are a lot of homes that are already lacking return air.

lack of return air can be the cause of quite a few problems, for instance:

-furnace cycling on faceplate limit (getting too hot)
-air conditioning coil icing up and slugging liquid to compressor(not enough air flow)

Have your furnace and air clean and checked to make sure that your system isn't lacking return air now. otherwise I recommend finding a way to get that 7" return back into the hallway. (do not put the return in the bathroom to avoid letting the whole house smell you duece)

tom m

This is possible I believe the system didnt originally accomadate the unfinished attic which is now finished with 2 supply feeds. The hall return would have balance the air flow, it never worked they say most likely from the closed doors. I plan on trimming the bottom regardless.
This is good info but there is no where to route this back into the hall unless you put it in the walk way. BTW Once I traced the line I canceled out the idea of locating it in the bath. This house could probably use a fresh air duct on the return side it doesnt have one to help here. Im am not a HVAC guy at all so bare with me here...... I was considering a high powered bathroom fan would circulate air but only when the bath is used. I was exploring a multi port exhauster with possible jump ducts to the bedrooms. Even this idea doesnt address your concerns above and unless I get one that operates on a humidistat or timer it would only work when someone uses the bathroom. What if I took the line in the basement and directed it outside? What would be involved as far as an in line filter or whatever? Doing this with exhaust upstairs could be an improvement to the system. I may give the HVAC guy a shout come monday and let himquote me or advise me.

Aceinstaller

When capping the return, you will be restricting the amount of air returning to the furnace to be treated(heated or cooled). fresh air is something that is necessary in concrete homes or foam insulated homes with little or no infiltration from the outside. it is also used in commercial applications for buildings with high occupancies.

exhausting the air from the bedrooms is not a good solution. It will end up exhausting treated air outside that you have used energy to heat or cool. and it will put the home into a negative pressure causing outside air to infiltrate the home through the walls. basically costing you a lot more money to heat your home.

I would recommend calling a local heating contractor to evaluate your ductwork, and ask them if they can find a way to run a return trunk into the attic (typically through a closet, or unused space) and connect all of the bedrooms individually to this trunk.

If you really want fresh air incorporated into the ductwork, there are some bypass hepa filtration systems that do this pretty efficiently. ask your local contractor.

hope this helps

tom m

I brought in a service tech for the unit and moved the return over a closet door on the first floor hall. I still dont think its any better. They satisfied the return volumn yes but its close to the unit so it pull maybe too much so much that now I wonder if the other returns are being weakened. Cant win with this stuff. Its really not my problem anymore but it bugs me. Perhaps I should put an adjustable grill so I can tone down the air pull.