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

Jells

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

EBEBRATT-Ed

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

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