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Does this CGi gas boiler direct vent setup require double wall pipe or not?

Options
Jells
Jells Posts: 689
in THE MAIN WALL
image.png

I've contracted to have the masonry chimney demoed and replaced with the snorkel direct vent, but they claim it doesn't need to be double walled. It seems like a liability to me to have a unprotected fully hot vent at ground level!

This is from the manual, page 15. https://www.weil-mclain.com/wp-content/uploads/CGi-S4-Boiler-Manual-0124.pdf

Obtain vent system components

  1. The following special gas vent systems comply with UL-1738
    and ULC-S636 standards and are certified by CSA as the only
    systems suitable for use with CGi boilers (all 3” diameter):
    • Heat-Fab, Inc. Saf-T Vent®
    • Flex-L International, Inc. StaR-34
    • Z-Flex®, Inc. Z-Vent II
    • ProTech Systems FasNSeal

Can/should/must I require they use double walled pipe?

Previous discussion of options https://forum.heatinghelp.com/discussion/204544/what-to-do-with-this-odd-boiler-vent-setup-redirecting-the-vent-into-the-old-chimney#latest

Comments

  • EBEBRATT-Ed
    EBEBRATT-Ed Posts: 21,090

    Yes. it has to be 1 of the 4 pipes above

    • Heat-Fab, Inc. Saf-T Vent®
    • Flex-L International, Inc. StaR-34
    • Z-Flex®, Inc. Z-Vent II
    • ProTech Systems FasNSeal

    Listed for the install. Nothing else can be used.

  • hot_rod
    hot_rod Posts: 28,434

    I think you have a class 3 requirement if that is a fan assist boiler.

    So the common double wall B vent cannot be used. Stick with the list.

    Double walled is used when you have reduced clearance requirements

    IMG_1645.jpeg
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Jells
    Jells Posts: 689
    https://forum.heatinghelp.com/discussion/comment/1906046#Comment_1906046

    So if they can't use double wall, what do I do to make it safe? I don't have small kids but theoretically it's a burn hazard. Do I need to put chain link fence around this thing??

  • EdTheHeaterMan
    EdTheHeaterMan Posts: 12,772

    Can you show us a photograph of the location for the expected termination of the vent pipe? Are you sure you need it to be a "Snorkel" configuration?

    The Category III vent is for exhaust temperatures that usually range above 140°F, so that is somewhat of a concern when it comes to actually touching the metal vent pipe while the appliance is operating. I might place a metal cage around the vent pipe, with a clearance of about 3 inches from the pipe, using a material that will not allow fingers to get too close to the hot vent pipe. Placing a chain link fence will do the same thing however you would need to be farther away since a small child can fit their arms thru the fence. I have seen expanded metal mesh that will do what you are suggesting.

    Screenshot 2026-10-10 at 10.48.43 PM.png

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

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