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Are unenclosed GFA furnaces in kitchens legal?

0 votes
I recenlty purchased a 20's-era multi-unit apartment building in the City of Chicago. Before talking to licensed contractors who want to upsell me, I'd love your unbiased wisdom. Thanks!

The previous owner installed GFA furnaces in the corner of each kitchen without any enclosure. They are vented directly to through the outside wall (some PVC some metal), have cold air return along the bottom of the wall from the living room intake, and ductwork soffits along the ceiling. Some are older, some are newer. There are several things wrong with the installations that I plan to have corrected. The big question is, other than for aethetics, do furnaces have to be enclosed? If so, are the clearances just "per manufacturer" or does the City have more stringent requirments.

If salvaging the existing systems prooves unwise, I may start over. Alas, the related question is, if I start over, what is the most economical and legal system to install and/or run for small (500 SF) 1-bedroom units in Chicago? (e.g. baseboard, direct vent, GFA, etc.)  There are no utility closets currently - so I would have to build one if it's required.

asked in Heating and AC by dw (120 points)
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1 Answer

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Hi DW,

smiley My unbiased wisdom? Well, it will depend on who’s going to have (if anyone) a final word in accepting this installation (e.g. Chicago Building Department, Peoples Gas).
The code says nothing about having (or not) the forced air furnace installed in a kitchen or enclosure requirement (in general), however, it requires the appliance to be protected from damage. Kitchen may not be a dangerous area for a furnace but since the apartment will be rented you have to think about the tenants, their kids, etc. 
Furnace service panels have no padlocks and getting them off the appliance (in some models) is extremely easy, even for a child or by accident. Therefore, even if this may not be required, I would definitely put it behind a lockable door. Clearances per manufacturer’s installation guidelines / often depend on the appliance’s type and model.  
Combustion air is not an issue if all those furnaces are direct vent type which means they use only exterior air for the combustion process:
  • high efficiency, condensing furnaces with 2 PVC pipes (exhaust and intake)
  • single PVC with double wall
  • and around 80 % efficiency  furnaces with two metal pipes (some older models, I don’t think they make them anymore). 
If some of those furnaces are using interior air for combustion you may have a problem. The square footage of those units may not be sufficient to provide enough fresh air to support clean burning.
Second issue would be the cold air return but I’m not sure if I understand its current location (kitchen cold air return is not permitted, living room may be OK, or both (seal the kitchen one)), which must be a minimum of 10 feet from any open combustion source (furnace combustion chamber, water heater, and fireplace), unless located in a separate room.
If some of those regular type furnaces are venting through the side wall… well, you will need a chimney or probably replace them with new high efficiency furnaces.
If starting over… I would go with small high efficiency units, dual PVC (vent/intake), reuse existing air supply ducts, install air return wherever most efficient / permitted, and build a closet around them (kitchen or any other location that makes sense, hard to say for me because I can’t see the layout). If you have a new electrical service and enough power to handle electric forced air furnaces… well, for as long as some of the existing gas ones can be salvaged. 
You can find more information on my website in HVAC / Heating System category (http://checkthishouse.com/category/hvac/heating-system/)
And the following publication - http://hollub.com/UsefulLInks/construction_guide.pdf starting around page 18
Let me know if you have more questions.
answered by darekrudy (21,730 points)
Thanks for the quick response and insight!  

- cold air intake is technically in a separate room (the living room) so I think I'm ok there.

- electrical has been upgraded since the 20's, but I doubt there's enough to do electric GFA

 - Putting new direct-vent units in the same location as the previous units - connecting to the existing ductwork  and adding a new enclosure - may work if they are smaller than the existing units and have tight clearance specs.  

What size are some of the smallest units on the market? Specific model suggestions would be great.

Thanks again!

Any time DW,

Since I’m not a heating contractor I can’t really grade the furnaces, you’d have to go over some reviews and pick one. You can look at this site: http://www.hvac-for-beginners.com/furnace-ratings.html or this one - http://www.furnacecompare.com/furnace_ratings.html, or some other review sites.
The BTU’s rating will vary between the manufacturers but the lowest is usually slightly under 40K. In most cases the lower rating may not have much impact on the dimensions, a few inches at the most.
great advice!  Thanks
You are welcome DW,

Any time.