combine tankless flues

keyote

Ive got a rental on top floor that i have started to build with a rheem 64 tankless unit under a future stair behind the bath room. its 3/5 vent goes right out a 13" brick exterior wall. directly under  floor, below im building my own unit with another bathroom and its own rheem 64  Id like to gang the two flues together and have only one wall penetration but rheem and metal fab are just too stupid to reach or answer questions in any way that instills confidence that some idiot is reading from a script in fact they dont even answer this question and refer you to a paid  service. anyway im aware of the issues but also think ive seen this done on large commercial jobs any ideas?

unclejohn

The answer

Is no you can't.http://www.rheemtanklessonline.com/rheemtanklessventing.html

keyote

tankless flues

dont see anywhere on the link the question is addressed. i realize of course they must be fan powered but  a backdraft damper might solve that 

HDE

Appliiances come with installation instructions

Read it!

"The water heater must be vented to the

outdoors as described in these instructions.

DO NOT connect this water heater to a

chimney. It must be vented separately from

all other appliances."

chimney. It must be vented separately from

all other appliances."

"The water heater must be vented to the

outdoors as described in these instructions.

DO NOT connect this water heater to a

chimney. It must be vented separately from

all other appliances."

chimney. It must be vented separately from

all other appliances."

WARNING "For multiple unit installation, a minimum

distance between vent terminations must be maintained to

prevent recirculation of vent gases. Maintain a center-to-center

distance between vent terminations of 19 inches (48 cm) for two

unit installation. Maintain a center-to-center distance between

vent terminations of 21 inches (53 cm) for three or more unit

installation." "For multiple unit installation, a minimum

distance between vent terminations must be maintained to

prevent recirculation of vent gases. Maintain a center-to-center

distance between vent terminations of 19 inches (48 cm) for two

unit installation. Maintain a center-to-center distance between

vent terminations of 21 inches (53 cm) for three or more unit

installation."



The life you save may be your own

RobG

Eternal

Check out this link. The Eternal brand of tankless water heaters can apparently have a common vent.

Rob

http://www.heatinghelp.com/forum-thread/141150/Four-Hybrid-Eternals-for-a-Restuarant-photos8

HDE

So can many other tankless brands

As long as they're serving the same domestic water system