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Author Topic: Combine Venting sizes  (Read 858 times)

Offline Demon2

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Combine Venting sizes
« on: May 11, 2016, 04:54:32 PM »
I have multiple boilers cascaded but now have a bunch of 2" pipes sticking out everywhere. How many 2" can I combine into each other and what size pipe do I have to use. Can I put 3-2" into 1-4" or do I need to jump to 6" 636 pipe .. They are 3 - 120k btu boilers

Offline Admin

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Re: Combine Venting sizes
« Reply #1 on: May 11, 2016, 07:28:13 PM »
From the B149.1-10 Gas Code,

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Clause 8.10.4 - A special venting system or a BH venting system shall be installed in accordance with the terms of its listing and the appliance and vent manufacturer’s certified installation instructions.

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Clause 8.10.6 - An appliance that operates at a positive pressure shall
(a) not be connected to a venting system serving any other appliance; and
(b) only be connected to a venting system certified for positive pressure venting.

Offline walker

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Re: Combine Venting sizes
« Reply #2 on: May 18, 2016, 06:40:39 AM »
Some of the new Navien boilers can be common vented.

The NHB-110 and NHB-150

Offline Admin

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Re: Combine Venting sizes
« Reply #3 on: May 18, 2016, 07:36:06 AM »
I was curious and had a look at the Navien NHB-110 and NHB-150 installation manuals, and found this on page 41,

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Do not connect the boiler vent to a vent for any other gas boiler or vent stack.

The manuals I read can be downloaded - Here

I did find a document on the net, which seems to allow common venting.  It's strange that their installation manuals don't include this information.  You can download it - Here

Offline rmuntz

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Re: Combine Venting sizes
« Reply #4 on: May 25, 2016, 01:30:16 PM »
This is from the Ontario Amendments, for now anyways...

 
"Section 4.1.4 is revoked and the following is substituted for it:
4.1.4 Where a conflict exists between the manufacturer’s certified installation
instructions and this Code, the most stringent of the two shall prevail."