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Draw furnace return air through furnace closet

cda said:
Is your unit on a platform where

The return air moves from the floor,, through the fillter,, into the unit??

Kind of like this::;


https://ixquick-proxy.com/do/spg/show_picture.pl?l=english&rais=1&oiu=https://basc.pnnl.gov/sites/default/files/HVAC2284_AHUCloset-fig%2018-djb-01-06-15.JPG&sp=6a598fef253a5915a81e14a13fc87114
Click to expand...

No, the unit is not on a platform. The challenge is that the unit is set back in the closet with storage space in front of it, so I don't think a platform would work well here.
 
Tim D said:
No, the unit is not on a platform. The challenge is that the unit is set back in the closet with storage space in front of it, so I don't think a platform would work well here.
Click to expand...


Just wondering mine sets on a platform on the corner of a room/ hallway

Two sides have vents
I can add one more


I wonder why yours necks down so much, once you get to the actual unit
 
cda said:
Just wondering mine sets on a platform on the corner of a room/ hallway

Two sides have vents
I can add one more


I wonder why yours necks down so much, once you get to the actual unit
Click to expand...

I tried to upload an image but looks like the site only accepts web links. The short answer is there is just not enough space. There are about 4 inches between the unit and the left wall of the closet -- this space is used for the return duct. Through that left wall is the building common space, so no expansion options there. There is no space at all to the right of the unit (it's up against the closet wall). I'm guessing they built the closet too small by mistake, and by the time they realized this, it was too late/expensive to fix.
 
Tim D said:
I tried to upload an image but looks like the site only accepts web links. The short answer is there is just not enough space. There are about 4 inches between the unit and the left wall of the closet -- this space is used for the return duct. Through that left wall is the building common space, so no expansion options there. There is no space at all to the right of the unit (it's up against the closet wall). I'm guessing they built the closet too small by mistake, and by the time they realized this, it was too late/expensive to fix.
Click to expand...


You have to be a paying sawhorse to post pictures direct.

But if you can make it into a link

You can post the link. That tech is also above my kindergarten diploma.
 
cda said:
You have to be a paying sawhorse to post pictures direct.

But if you can make it into a link

You can post the link. That tech is also above my kindergarten diploma.
Click to expand...

I just tried to add in the image -- let's see if it works. The part circled in red is the current return. As you can see, space is tight!
cUEtd6
 
Sounds like sacrifice some space or find the best way to add more return

Hopefully your ac guy told you the unit can get damaged by the way it is now, at least that is what my guy said about restricted return
 
cda said:
Sounds like sacrifice some space or find the best way to add more return

Hopefully your ac guy told you the unit can get damaged by the way it is now, at least that is what my guy said about restricted return
Click to expand...

Yes, that's exactly what he said. The low airflow doesn't move enough heat, and eventually the heat exchanger can get worn out. I plan to have him implement a fix soon. Thanks again!
 
steveray said:
Central return system sucks (pun intended) but it is the cheap way to do it, which makes it the common way (but so does a poorly designed duct system). You could try cutting a small return at the unit in the closet and in the door to get some more return air back...Are there gaps under the doors in all of the rooms? If there are supplies in all of the rooms but no returns, door undercut is important to keep from trying to "inflate" the room and allow the return to work....
Click to expand...

You will probably end up doing what Steveray posted from a cost standpoint. It's not ideal, but it does work.

Just to add to Steveray's post, another option is to add air transfer grilles between rooms and the hallway. Some people prefer this look to the undercut doors.
 
cda said:
That picture works

Stick a jack under it

Cut some of the duct off on top

Make some room for more return on the bottom
Click to expand...

Tough to see from the pic, but there is another bottleneck in the return duct where it enters the closet. There is no room for expansion unfortunately. So I can add more return close to the machine, but the duct will still be restricted.
 
tmurray said:
You will probably end up doing what Steveray posted from a cost standpoint. It's not ideal, but it does work.

Just to add to Steveray's post, another option is to add air transfer grilles between rooms and the hallway. Some people prefer this look to the undercut doors.
Click to expand...

Thanks tmurray. I agree, that's probably the best option at this point. I appreciate the help!
 
Tim D said:
Hi,

I have a Ducane forced air natural gas furnace with sealed combustion (PVC intake and exhaust pipes that vent directly to the roof), and the system was installed with a very undersized return duct, resulting in low airflow. One option a contractor recommended to fix it is to remove the old return duct, cover the hole where the return air enters the machine with a filter, and cut a louver in the door of the furnace closet. This would allow the system to draw air from the main living space of the unit, through the louver, into the closet, and directly into the return of the machine through the filter (no return ductwork).

I think this would solve the low airflow problem, but is there any issue with drawing return air through the furnace closet? The combustion is sealed as I mentioned, but my concern is that if there ever were an exhaust leak, carbon monoxide could get sucked into the return and be spread throughout the house.

Would this setup be a code violation? I'm in Massachusetts.

Thanks in advance,
-Tim
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Can you do this fix and also bring another return duct from upstairs??


Is your unit upstairs or downstairs ?
 
cda said:
Can you do this fix and also bring another return duct from upstairs??


Is your unit upstairs or downstairs ?
Click to expand...

The unit is downstairs. I'd love to bring in another return duct from upstairs but there is no room (without considerable expense).
 
Tim D said:
The unit is downstairs. I'd love to bring in another return duct from upstairs but there is no room (without considerable expense).
Click to expand...


I was wondering about the idea of vents in closet door

Plus just an duct from upstairs that also dumps open, into the closet


Anyway you have your question answered

Plus some ideas

With your ac company get the best results you can

Hate to say might be a little trial and errror
 
cda said:
I was wondering about the idea of vents in closet door

Plus just an duct from upstairs that also dumps open, into the closet


Anyway you have your question answered

Plus some ideas

With your ac company get the best results you can

Hate to say might be a little trial and errror
Click to expand...

Yes, trial and error for sure. We've already had some improvement, so that's encouraging. Thanks again for all the help -- I really appreciate it.
 
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