# 2 tankless



## Drewp311 (Sep 17, 2011)

2 rheem tankless tied together.


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## Bayside500 (May 16, 2009)

are those flex connectors on the gas ?


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## Drewp311 (Sep 17, 2011)

Here is a bigger shot of it.


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## Leach713 (Nov 1, 2013)

No sediment trap or unions?
Either way good work


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## plumber tim (Jul 4, 2013)

What is the BTU and efficient rating on those tankless ?


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## Drewp311 (Sep 17, 2011)

199,000 btu. Around 85% efficient.


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## Leach713 (Nov 1, 2013)

plumber tim said:


> What is the BTU and efficient rating on those tankless ?


I see where you going 

Undersized gas?


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## plumber tim (Jul 4, 2013)

Leach713 said:


> I see where you going
> 
> Undersized gas?


Yes sir those gas flex connectors are only good for about 135,000 BTU's Says it right on the tag.


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## Leach713 (Nov 1, 2013)

plumber tim said:


> Yes sir those gas flex connectors are only good for about 135,000 BTU's Says it right on the tag.


Lol I never notice or paid attention , now I know why one of my journey man always went either hard pipe or gas tite csst.


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## plumber tim (Jul 4, 2013)

Those look like brass craft CSS-C gas flex connectors that are 3/4" pipe thread x 1/2" flex. Brass craft makes a CSS-B gas flex that is 3/4" the entire way not just the pipe thread.


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## Tommy plumber (Feb 19, 2010)

It looks like in the bottom picture a black iron 3/4"x1/2"x3/4" tee {can't see it very well}. He'll need to replace that with a full 3/4" tee and run 3/4" lines up to the units.


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## Drewp311 (Sep 17, 2011)

Negative. That is 1x3/4x3/4 tee. 3/4" going to both units. And the flex lines are 7/8" gas flex lines made for tankless w/h's rated at 220,000 btu.


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## Plumbworker (Oct 23, 2008)

is this how rheem lays out the water piping for multiple units in their manual?


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## johntheplumber (Feb 11, 2013)

How far is the meter from that installation?


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## johntheplumber (Feb 11, 2013)

And are they tied together with a multiple unit controller so they both don't fire every time any water is turned on?


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## Plumbworker (Oct 23, 2008)

johntheplumber said:


> And are they tied together with a multiple unit controller so they both don't fire every time any water is turned on?


yeah i dont see how there's gonna be alot flow through that right hand heater the way is piped..


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## Drewp311 (Sep 17, 2011)

johntheplumber said:


> How far is the meter from that installation?



Gas meter is on the opposite side of the wall about 3' away. Nothing else is on the gas meter. Only the tankless.


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## Drewp311 (Sep 17, 2011)

johntheplumber said:


> And are they tied together with a multiple unit controller so they both don't fire every time any water is turned on?



Yes there is a connector that links them.


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## johntheplumber (Feb 11, 2013)

---


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## Drewp311 (Sep 17, 2011)

johntheplumber said:


> ---


So let's just say there is 600 CFH available. Each unit is 180 CFH. That means there is 240 CFH still available assuming that both units go into high fire, which is not likely that they will both do very often.


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## Leach713 (Nov 1, 2013)

Plumbworker said:


> is this how rheem lays out the water piping for multiple units in their manual?


Right tankless should of had it own branch of the main...

I have seen regular water heater tie like that in series


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## Drewp311 (Sep 17, 2011)

Leach713 said:


> Right tankless should of had it own branch of the main... I have seen regular water heater tie like that in series




http://www.rheem.com/pdfs/_temp/11000Series/11126.pdf

http://www.spiritgroupinc.com/wp-content/uploads/Piping-Diagrams_MAIN.pdf


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## love2surf927 (Dec 22, 2011)

Everyone's trying to rip this guys install and he has an answer for all of them lol, love it.


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## SewerRatz (Apr 25, 2009)

As long as the heaters are piped in parallel be it first in last out or uneven feed and output they will be fine .

The heaters have flow sensors, and flow control valves. The system controller will adjust the flow control valves accordingly to allow the right amount of flow from the second heater.

Remember both heaters do not fire at the same time. Only one heater turns on during initial water usage. When the water usage reaches 80% capacity of the heater that is on, the system controller will turn on the second unit and split the flow between each unit.

I feel all installs especially residential should be installed with at least two units. Not only to meet maximum demand(all hot taps on) but as redundancy in case a unit needs to be taken out of service for repair. Parts can take upto several weeks to get.


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## Plumbworker (Oct 23, 2008)

Drewp311 said:


> http://www.rheem.com/pdfs/_temp/11000Series/11126.pdf
> 
> http://www.spiritgroupinc.com/wp-content/uploads/Piping-Diagrams_MAIN.pdf


Yeah its still not piped reverse return as per rheem.. Since the right hand heater is the last in it needs to be the first out..


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## plumberkc (Jun 23, 2011)

Why didn't you just add the union and run iron pipe all the way? Or at least add a drip leg, that wouldn't pass here.


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## Plumbworker (Oct 23, 2008)

plumberkc said:


> Why didn't you just add the union and run iron pipe all the way? Or at least add a drip leg, that wouldn't pass here.


I know.... how hard is it to run that extra 2' of pipe to the heater?...

He had a bunch of answers for all the other questions from other members.. but has ignored my question about the lack of proper reverse return manifold..

when you post pictures of you're work on the zone you're gonna get knocked..


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