# Need advice on multiple tankless heaters



## Green Country (Mar 6, 2009)

I've been asked to replace two power vent tank type water heaters with six tankless heaters. They also have a third power vent tank that they want to keep and have as storage. 

The three current tanks are ran parallel. What is the best way to hook all these up so that the 100 gal tank can be used as storage? Would I have to put all the tankless units in series with the 100 gal tank (6 tankless in parallel and then running into the tank)?

If I just ran them all in parallel and connected to the existing line it seems like they wouldn't get any storage benefit from the tank, is that correct?


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## UN1TED-WE-PLUMB (Oct 3, 2012)

http://www.tanklesswaterheatersdirect.com/shop/images/takagi_tk2_indirect.gif


This is what you need to do


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## Plumbus (Aug 4, 2008)

Check with tech support of the manufacture of the product you plan to use.


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## dhal22 (Jul 30, 2010)

Plumbus said:


> Check with tech support of the manufacture of the product you plan to use.



I wouldn't install them without the support (WARRANTY) of the manufacturer.

David


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## allanbutts (Sep 9, 2014)

dhal22 said:


> I wouldn't install them without the support (WARRANTY) of the manufacturer.
> 
> David


"they're wrong, they're wrong , they're wrong " but dhal 22 is right , I have design built some great and efficient systems , with complete detailed spec sheets , and submitted to code & inspection and state of ga health dept ; only to be shot down because they don't have the intel to approve anything based on there own science ( or lack of ) usually to be replaced with some antiquated elec tank crap with a sticker that meets the form they have in office , definitely use mfg spec or recommendations


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## dhal22 (Jul 30, 2010)

As much as I love Eternal water heaters, I won't use them in commercial. The sizing dept there knows good and well that Eternal isn't a good fit for commercial apps so they always spec a minimum 100 gal storage tank no matter how small the kitchen. I use Noritz/Rennai in commercial applications.

David


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