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-   -   Forced Hot Air Heat - No Cold Air Return (http://www.diychatroom.com/f17/forced-hot-air-heat-no-cold-air-return-160642/)

DIY12 10-20-2012 04:58 PM

Forced Hot Air Heat - No Cold Air Return
 
Greetings all - New to the site and looking for some input. I've done quite a bit of searching, and I'm not having much luck with my inquiry.

Some background:
Traditional New England Style 3 family apartment building. I reside on the 2nd floor, and have a separate heating system from the other tenants. Double Parlor setup with a BR off of the LR, a 2nd BR off of the DR, and then a 3rd BR off of the Kitchen. 3 Supply ducts from the furnace feed the apartment, in the same fashion I described the layout. 1 duct supplies LR and BR, 2nd duct supplies DR and 2nd BR, and the last supplies the 3rd BR and the Bathroom.

There is no Cold Air Return from the apartment feeding the furnace, to recirculate the air. It's been this way for well beyond my 12 years here.

My Question:
We rarely use the supply registers feeding the DR and the Middle BR, and typically have them closed. I want to disconnect this supply leg, and get the appropriate duct work and attach it to the input of the furnace for a Cold air return. I understand that this would not be an optimal size for a CAR duct, but I figure it would be the least expensive fix at this point, as well as better than not having ANY return air from the apartment. The building is family owned, and the landlord (My Father in Law) isn't really up on repairing and keeping things running right. Thoughts, Suggestions? Thanks!

Missouri Bound 10-20-2012 08:37 PM

Return air to the furnace often is allowed by vents in doors or walls, not necessarily ductwork. If the furnace room has a return vent in the room you could disconnect one of the supply ducts there and use it as for air return. A few pictures would help quite a bit.:yes:

ben's plumbing 10-20-2012 09:08 PM

Iam sure your not going to like this.....1st have that furnace checked for cracked heat exchanger....Iam sure with out proper return air furnace is not running within proper tempeture rise ...which will damage the furnace ....12 yrs is long time...ben sr

beenthere 10-20-2012 09:15 PM

Whee is the furnace located.

DIY12 10-20-2012 11:12 PM

Quote:

Originally Posted by Missouri Bound (Post 1034713)
Return air to the furnace often is allowed by vents in doors or walls, not necessarily ductwork. If the furnace room has a return vent in the room you could disconnect one of the supply ducts there and use it as for air return. A few pictures would help quite a bit.:yes:

The furnace is located in the basement, and is a wide open area. The air intake is filtered, but is only drawing air from the basement. I'll post some pics of the furnace and the duct work in question tomorrow. Thanks.

DIY12 10-20-2012 11:17 PM

Quote:

Originally Posted by ben's plumbing (Post 1034730)
Iam sure your not going to like this.....1st have that furnace checked for cracked heat exchanger....Iam sure with out proper return air furnace is not running within proper tempeture rise ...which will damage the furnace ....12 yrs is long time...ben sr

Thanks Ben Sr. The heat exchanger would be the area of the furnace that the blower forces air through and up through the duct work? (Similar to a heater core in a car?). Is this something I can check myself, and would be relatively self explanatory? Or is this something a trained eye will be better suited to find?

The heat has always worked well for us, I'm sure it has been extremely inefficient however. I just finished sealing up all of the seams and gaps in the duct work with the proper UL foil tape and duct mastic. This is the next obstacle.

COLDIRON 10-21-2012 07:26 AM

Are you saying there are 3 heaters in the basement 1 for each apartment drawing air intake from the basement? If so get ready to do some major work.
Sounds like you need to get some paper and a pencil and inspect every inch of ductwork to see what is fed from what unit.

ben's plumbing 10-21-2012 07:36 AM

Quote:

Originally Posted by DIY12 (Post 1034821)
Thanks Ben Sr. The heat exchanger would be the area of the furnace that the blower forces air through and up through the duct work? (Similar to a heater core in a car?). Is this something I can check myself, and would be relatively self explanatory? Or is this something a trained eye will be better suited to find?

The heat has always worked well for us, I'm sure it has been extremely inefficient however. I just finished sealing up all of the seams and gaps in the duct work with the proper UL foil tape and duct mastic. This is the next obstacle.

you can not inspect heat exchanger.....need a pro.... the fact that its pulling return air from basement and is filtered..make me feel alittle better...but only 3-4 runs off furnace ...still would not be within the specs of tempeture rise....seems to me it would be cycling on and off high limit.....how big is furnace...btu...

beenthere 10-21-2012 08:47 AM

Are the other furnaces also pulling their return air from the basement.

If you try to use the supply duct from those 2 unused rooms, it may be too small and cause the furnace to cycle on its high limit, and may cause you no heat problems.

DIY12 10-21-2012 09:11 AM

Quote:

Originally Posted by COLDIRON (Post 1034914)
Are you saying there are 3 heaters in the basement 1 for each apartment drawing air intake from the basement? If so get ready to do some major work.
Sounds like you need to get some paper and a pencil and inspect every inch of ductwork to see what is fed from what unit.

The first floor is heated by an oil fired boiler, water filled radiators. This furnace is on the other side of a wall, in a separate section of the basement. It is not enclosed. The third floor has a gas space heater for the main heat source. The forced hot air is for my apartment only.

DIY12 10-21-2012 09:18 AM

Quote:

Originally Posted by beenthere (Post 1034944)
Are the other furnaces also pulling their return air from the basement.

If you try to use the supply duct from those 2 unused rooms, it may be too small and cause the furnace to cycle on its high limit, and may cause you no heat problems.

So it would be better to possibly leave it alone, as too small of a return can cause more issues? My mindset was that having at least some recirculation or exhange of air would be better than the current setup.

beenthere 10-21-2012 09:45 AM

Quote:

Originally Posted by DIY12 (Post 1034963)
So it would be better to possibly leave it alone, as too small of a return can cause more issues? My mindset was that having at least some recirculation or exhange of air would be better than the current setup.

If the furnace needs a min of say 600 CFM, and your return only provides 200 CFM. Then the heat exchange will over heat.

DIY12 10-21-2012 09:51 AM

Quote:

Originally Posted by beenthere (Post 1034976)
If the furnace needs a min of say 600 CFM, and your return only provides 200 CFM. Then the heat exchange will over heat.

Understood. That makes sense. Ill post some picks of the furnace, etc in a couple of hours, as soon as I can get home.

Missouri Bound 10-21-2012 10:02 AM

Quote:

Originally Posted by DIY12 (Post 1034963)
So it would be better to possibly leave it alone, as too small of a return can cause more issues? My mindset was that having at least some recirculation or exhange of air would be better than the current setup.

:huh: Help me understand. The furnace does have some return, but not from your apartment....is that correct? If so, then using one of the supplys as a return won't hurt anything, in fact it may help the heat in your apartment. But as was eledued to earlier a furnace needs a certain minimal amount of return for proper operation.

DIY12 10-21-2012 02:22 PM

Quote:

Originally Posted by Missouri Bound (Post 1034993)
:huh: Help me understand. The furnace does have some return, but not from your apartment....is that correct? If so, then using one of the supplys as a return won't hurt anything, in fact it may help the heat in your apartment. But as was eledued to earlier a furnace needs a certain minimal amount of return for proper operation.

Correct. This is where the air is drawn in, filter is brand new.
http://i59.photobucket.com/albums/g3...ost/Intake.jpg


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