Condensing furnace Exhaust, Distances from window, electric and gas meters

Joel Parness · 03-12-2008, 05:56 PM

Hi Fellows,

I've searched the past threads but I couldn't find The information on this question, I was hoping that maybe you folks could help me out.

Looking at this picture, It looks like the furnace exhaust is too close to the window(s).

Not only that, there's the gas meter and the electric meter.

I looked up the installation instructions for a similar Carrier gas Furnace, The exact model was not available on their site, but this one is real close. Here it is. See page 31.

http://www.docs.hvacpartners.com/idc.../58mxb-1si.pdf

The diagram seems to suggest (to my surprise) that the clearance to the window is OK but there may be a problem with the electric meter.

I was wondering if you know of any code references or even past threads that may provide some guidance here. I always thought that you needed to be at least 4 feet from the bottom and sides of an operable window. but this appears to be incorrect.

I can't find anything on this in the Massachusetts plumbing and gas codes that address this question. The meters were changed to the digital type by the local electric company within the last 5 years. I estimate that the furnace was installed in 1996.

Any comments, or imput would be hugely appreciated.

TIA...J.P.

Similar Threads:

**Billy Stephens** · 03-12-2008, 06:51 PM

Joel,

3 ft from operable window is what I have on the Electrical Service.

Gas meter looks OK.

Install instructions in your post says if below 100,000 btu clearance is 12', and 36' if over 100,000 btu.

Brian E Kelly · 03-12-2008, 07:01 PM

Not sure what your area calls for about clearences but around me in NY State we need a 4' clearence from any opening (window, door) and in my neck of NY the vent must be a least 18" off the ground level. We must also be away from the meters (gas & elect.) at 36" which is also indicated in the building codes books. Best bet is to call the local fuel supplier as they ciould answer your questions over the phone then there is no question.

David Banks · 03-12-2008, 08:29 PM

Joel. Billy is correct. The 4 ft clearance is for Mechanical Vents. What you have is a direct vent appliance.
New MA code book refers you to Fuel Gas and Plumbers Code. In MA is 248 CMR. This refers you to NFPA-54 National Fuel Gas Code.
NFPA-54. 12.9.2-Mechanical Vent.
12.9.3-Direct Vent.

248 CMR 4.00: Introduction and Massachusetts Modifications
IRC says basically the same thing. New Code is based on 2003 IRC.

Kevin VanderWarf · 03-13-2008, 04:58 AM

There is also a rule on inside corners that used to be in the Rheem factory specs, I haven't seen those specs in awhile.
Not sure if the corner where the chimney meets the siding would count or not.
At first glance that location just looks all wrong.

Joel Parness · 03-14-2008, 08:32 AM

Hi guys,

Thanks to all that replied. I actually forgot I had one of those Code Check books right in my car the whole time...D'OH!

The AHJ sez to go with the manufacturer's instructions which seems to make the electric meter more of a problem than the window.

Take care,

J.P.

**Eric Barker** · 03-14-2008, 06:20 PM

For clearances around exhausts and intakes you really have to go by the manufacturer's specs - they do vary and codes will defer to them. I have seen specs that say the two pipes must be on different walls. You will find specs on distances to corners or in this case the chimney. Without the specific manual for the furnace in the home you can only surmise what is required. Code references will not help you with this.

Sal Soto · 03-16-2008, 11:48 AM

I've been with the gas utility company in my area for 34 years and have a current master plumbers license and currently hold a position as a Safety Coordinator with the company. The city pretty much allows to dictate where our gas meters are located. Our company policy states that any opening into a home door, window, dryer vent, combustion air, etc. or any source of ignition such as a condensing unit, electric meter, etc. has to have a 3 ft. clearance to our gas meter.

**Bob Harper** · 03-16-2008, 01:00 PM

You can state that the current gas and mechanical codes require 4ft from openings and 3ft. from the meter. However, Eric is basically correct in that the appliance listing, IF more stringent than the codes will apply. The most restrictive applies. Keep in mind this installation is 12 yrs old. No harm in stating how it stacks up against current codes. It may not have been illegal at the time of installation but we know more now than we did then.

FYI, Mass now requires ALL vent terminations at least 4ft. above grade due to a CO fatality from a blocked gas direct vent by snow. No requirement to retrofit but still can be made aware of this new state law.

HTH,
Bob

David Banks · 03-16-2008, 05:17 PM

FYI, Mass now requires ALL vent terminations at least 4ft. above grade due to a CO fatality from a blocked gas direct vent by snow. No requirement to retrofit but still can be made aware of this new state law.

HTH,
Bob

Bob. Where did you see that. Never heard of it. If you have a link or the code please post.
Thanks
Dave

**Ken Amelin** · 03-16-2008, 07:08 PM

NFPA54, fig A.12.9 says that the minimum clearance for a direct vent terminal below a window must be at least:

a. 12 inches below a window (50k btuh input or greater)
b. 12 above grade.

MA code follows NFPA54.

MA code also says that all direct vent appliances must have a device that will shut off gas to the burner in the event of sustained backdraft