The joy of concentric venting....

[bob_the_builder]

I guess a good question to ask if anyone here is Canadian...

In my area, we have

http://www.saskpower.com/customer_service/assets/codes_of_practice_gases.pdf

which override the gas code in our jurisdiction. On page 34 & 35 you can see clearances for terminations.

I am venting three appliances, all system 636 3" (Two 75 gal. water heaters and one high-eff furnace). Based on what I see in this code, as long as I am 12" away center to center from each concentric vent I should be okay. Now the manufacture instructions say that if I vent three concentric vents, two can be grouped together (12" center to center receptively), and the third must be 36" away.

Do I follow the manufacture instructions, or the gas code?

Also, am I correct to assume there are no clearances required for a stale exhaust from an air exchanger, just the inlet which according to this code is 6'?

Thanks in advance!

[rich pickering]

Where in the code or the code of practice does it say that you can't group vents?

[bob_the_builder]

Where in the code or the code of practice does it say that you can't group vents?

Nowhere to my knowledge.

My questions is really if I should follow manufacture specs, or code of practices. Do manufacture specs supersede CoP?

[Greend88]

The most strict supersedes the other one. I think most codes say that what they have is the minimum requirement, and the most strict one should be followed. If the manufacturer recommends more then use the manufacturer but if for some reason a manufacturer states something less than code then you have to follow code.

[rich pickering]

Nowhere to my knowledge.

My questions is really if I should follow manufacture specs, or code of practices. Do manufacture specs supersede CoP?

For grouping vents, follow the manufacturer. But you have to allow for different types of appliances and manufacters.

Clearance to openings is fairly standard. Big issue is property line. Concentrics won't work if you are closer than 10' to a property line. (Local rule here)

You a GC or a plumber?

[bob_the_builder]

I am a plumber, but also a gasfitter.

I am phoning the inspector this am, and I will let you know what I find out.

[Moose]

That's your best option.. no use doing it twice.

[trouble time]

The manufactures instructions supersedes the code. It is sort of a catch-22 thing. The manufactures instructions are CSA and CGA approved.
Having said that I think you are doing the right thing by asking the inspector, it is his/her job after all.

:putergreet:

[rich pickering]

Where are you located?

[bob_the_builder]

Well, here is the verdict:

The authority having jurisdiction said to follow the minimum for combustion air clearances in this case 12" as per the code I mentioned above, but to follow manufacture spec in regards to the 36" for the third concentric vent.

I was glad to have asked. I mean how often do you run multiple concentric vents?

[hvac.dave]

I've put this question to an inspector before, and was told that whenever there's a question between the code and manufacturer specs, always go with whichever one is strictest. In this case it would be manufacturer specs.