C.2.16 For Single Appliance Venting Applications

[DaveP]

C.2.16
For Single Appliance Venting Applications:
Where the vertical vent has a larger diameter than the vent connector, the vertical vent diameter shall be used to determine the minimum vent capacity and the vent connector diameter shall be used to determine the maximum vent capacity. The flow area of the vertical vent shall not exceed 7 times the flow area of the listed appliance categorised vent area, flue collar area, or draft hood outlet area unless designed with approved engineering methods.

Pretty much says no more orphaning hwt's on 5" liners?  We've done this in the past, but never on a 6", but it seems the intent is to get away from nat draft hwt's in the future.  Pretty hard to pull a 4" liner down 5" bvent, especially if screws/joints were installed improperly, let alone working at heights restrictions now.

Anyone interpret it different?

ie C2 - 20' 2' lateral 5" 165x80% = 132 to be used as min
           4" flue collar  4" 148x80% = 118 to be used as max

               

[Admin]

Download Director's Advisory FS-065-05 - Here

If your single appliance is at least 30,000 BTU's and equipped with a draft hood, you can use up to a 6" interior vent, provided you test for down draft.

[DaveP]

Thank you for that!  Interesting, I had not seen that one.

Nor have most of the Enercare techs red tagging these situations before replacing rental tanks that have been orphaned. We usually left them on the 5", if it was a 6" advised the customer they "may" have a problem in the future, when we switched the to high eff. furnaces.

And if they were tagged mostly selling them a tank, leaving things as they are, removing the tag, and telling them to call to get the rental picked up. 

As it refers to interior chimneys, in the situation of an exterior chimney, and with the addition of C.2.16, pretty much says you have to put in the appropriate size liner for the orphaned tank, no more smaller size preferred. We usually did the liner or PV tank, to avoid any condensation issues.

Thanks again
Dave