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Tankless gas water heater question

bob eck
bob eck Member Posts: 930
Are there any tankless gas water heater models that can be vented vertical with B Vent


  • DZoro
    DZoro Member Posts: 1,048
    All the 80% ones that I know of ask for the stainless....
  • newagedawn
    newagedawn Member Posts: 586
    what does the manufacture say?
    "The bitter taste of a poor install lasts far longer than the JOY of the lowest price"
  • bob eck
    bob eck Member Posts: 930
    I checked with Rinnai, Navien, Bosch and Purepro (Bosch private label models) non are for venting into Bvent piping.
    Just checking if anyone knows of a brand that can be vented that way. Most likely none are vented this wat. Thanks
  • kcopp
    kcopp Member Posts: 4,443
    The Bosch Aquastar (the one that had a Hydro generated spark) was B-ventable.... I think its out of production now.
    rick in Alaska
  • hot_rod
    hot_rod Member Posts: 22,262
    Paloma, now connected with Rheem, had some B-vent models. Low Energy in Colorado is an expert on tankless. tanklesswaterheater.com I think.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Jack
    Jack Member Posts: 1,047
    Rinnai has the RH180 which was a 90k B-vent tankless mounted on a 40 gal water heater. It needed 4" b-vent which on a retrofit can be a problem.
  • John Mills_5
    John Mills_5 Member Posts: 952
    I wouldn't. B-vent isn't meant for positive pressure. It's meant for a negative pressure like through the roof with a good draft.
  • rick in Alaska
    rick in Alaska Member Posts: 1,457
    Not all on demand water heaters are positive vent, so you would use the B-vent for them. I know the Aquastar and the Paloma used B-vent, and Jack definitely knows about the Rinnai line, so B-vent can be used as directed.