Big Maxx Horizontal Vent 50K BTU install

[cdsvt]

Hi,

I just ordered a 50K BTU Big Maxx and reading the manual see that Category III vent is required for residential installation (versus the Category I single wall vent that used to be required on the 75K BTU one I installed several years ago).

"Due to changes to Z83-8 2009 CSA2.6-2009, the use of single
wall B-Vent is no longer permitted as an acceptable material
when venting horizontally, this change covers both residential
and commercial installations. All horizontally vented units
manufactured after July of 2011 must be vented as a Caterory
III Unit/Utility Heater in compliance with UL 1738 & ULS636. "

Category III vent seems pricy!

What is the most economical source for 4" category 3 vent materials? I'll need a 90 degree elbow and 8'-9' of straight vent, plus a thimble and cap.

Thanks,
Charlie

 

[samert111]

Menards has Class III single wall vent material and yes it is expensive.

When you get your heater check the mfg date. Maybe it was made before July 2011 but I doubt it. Plus I suspect there is no difference in the actual heater. I think it's just a code change to the SS material for corrosion purposes. My horizontal vent is only 6' long and the exhaust gas doesn't have very far to go much less condense much. Personally, I think the single wall pipe will condense alot more than the double wall B vent that has been the norm before now but at least it will be inside an expensive SS pipe.

 

[cdsvt]

Looks like I'm going shopping for some category iii vent this weekend. Thanks.