Flexible plenum

[Reis Pearson]

I seem to recall some sort of bonding issue with these types of plenums... Anyone?

[Markus Keller]

Sorry, no clue about any bonding issue for those. That would be a new one to me. Is that a short radius 90 for the vent? I don't think those are allowed on the exhaust side. Can't swear to it right now though.