# Tankless change out



## Debo22 (Feb 15, 2015)

I’m looking to change out an existing Bosch tankless water heater. Existing has a 3” stainless vent and we’re not wanting to enlarge the roof hole. Also not looking to go condensing as there’s nowhere to drain without a pump. Any recommendations?


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## skoronesa (Oct 27, 2015)

If that's not a condensing boiler why is there a drain tube coming off the base of the exhaust?


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## ShtRnsdownhill (Jan 13, 2016)

I think all the units I put in are 4 inch exhaust and intake..and as skoso stated, you have a condensate drain hose at the base of the exhaust...I googled that model and...
VentingA condensate trap is integrated into the exhaust fluegas collar of the heater, the supplied condensate draintube MUST be installed  to it for proper removal ofcondensate from the trap. Additional condensate trapsand drains may be necessary; see chapter 3.6 forVentin 



https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwja3MjBr7fvAhWyc98KHfhWBI8QFjAAegQIBBAD&url=http%3A%2F%2Fwww.bosch-climate.us%2Ffiles%2F201009031229480.635ES_English_11.2007.pdf&usg=AOvVaw0FUg4FUy2xssQPx2nnGbKg


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## Debo22 (Feb 15, 2015)

skoronesa said:


> If that's not a condensing boiler why is there a drain tube coming off the base of the exhaust?


Very little to zero condensation comes out of them. I recently installed a Rinnai tankless that said it was non condensing and had that same drain port at the base of the vent. Install instructions also showed to hook up a drain to it. I called tech support to ask WTF, he said that it only needs a drain line if the vent is taller than 15 feet or has 90° right near the unit.


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## Plumbus (Aug 4, 2008)

If you can remove the roof flashing, making the penetration a little bigger to fit 3" plastic shouldn't be too much of a task.
Since I believe you are in Southern Calif (CPC), you are kind of stuck on the condensate discharge. Is that a laundry room in the pic? If so, and there is a sink, you might be able to run the drain into a y branch.


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## skoronesa (Oct 27, 2015)

Debo22 said:


> Very little to zero condensation comes out of them. I recently installed a Rinnai tankless that said it was non condensing and had that same drain port at the base of the vent. Install instructions also showed to hook up a drain to it. I called tech support to ask WTF, he said that it only needs a drain line if the vent is taller than 15 feet or has 90° right near the unit.


So if you're install condensing gas boilers that magically don't produce condensate than why are you worried about a drain? Just stub the drain tube out the wall, ain't like it's going to freeze! lolz


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## ShtRnsdownhill (Jan 13, 2016)

skoronesa said:


> So if you're install condensing gas boilers that magically don't produce condensate than why are you worried about a drain? Just stub the drain tube out the wall, ain't like it's going to freeze! lolz


dont forget an acid neutralizer for the condensate line....


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## skoronesa (Oct 27, 2015)

ShtRnsdownhill said:


> dont forget an acid neutralizer for the condensate line....


No, it's okay, he has a magic non-condensing condensing-gas boiler. 

I still want to know where the current drain goes, probably just into the grass.


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## ShtRnsdownhill (Jan 13, 2016)

skoronesa said:


> No, it's okay, he has a magic non-condensing condensing-gas boiler.
> 
> I still want to know where the current drain goes, probably just into the grass.


well if you read the install directions for " non condensing" tankless units, if the vertical flue goes over a certain length, they want that fancy drain fitting to get rid of condensation from the flue more than what the unit produces, I installed a condensing tankless and it had a special fitting at the base of the housing that condensate pretty much poured out as the unit runs, far more liquid than what would just come down the flue,and on that boiler if the flue went up over a certain length I would need that special fitting for condensate.. if a non condensing boiler had a short out the wall flue, then no special fitting is needed...


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## Master Mark (Aug 14, 2009)

looks to me like the condensation drain goes out the side of the house.
might as well send it to the same location......

I know that this it probably going to bring screaming howls from everyone but 
could you not install a Navian , which needs only a 2 inch pvc vent 
and simply adapt to that 3 inch SS vent going out the roof with a 3x2 fernco??
and re-use the air intake for the new unit?? just wondering ....

go ahead and tell me why this is wrong...


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## ShtRnsdownhill (Jan 13, 2016)

Master Mark said:


> I know that this it probably going to bring screaming howls from everyone but
> could you not install a Navian , which needs only a 2 inch pvc vent
> and simply adapt to that 3 inch SS vent going out the roof with a 3x2 fernco??
> and re-use the air intake for the new unit?? just wondering ....
> ...


just pump it full of sillycone..it will never leak.....lmao...


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## Master Mark (Aug 14, 2009)

ShtRnsdownhill said:


> just pump it full of sillycone..it will never leak.....lmao...


I was thinking duct tape..... or that shiney aluminum tape


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## Sstratton6175 (Jan 10, 2021)

You could also use cemtrotherm innoflue to vent it’s just slightly larger in diameter than the the AL29 stainless pipe. As far as the condensate goes. I agree with the other posts hook it back up just like it is now.


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## Master Mark (Aug 14, 2009)

Sstratton6175 said:


> You could also use cemtrotherm innoflue to vent it’s just slightly larger in diameter than the the AL29 stainless pipe. As far as the condensate goes. I agree with the other posts hook it back up just like it is now.



ACtually that SS vent can take some extreme heat, and with a navian the heat is so light coming off the unit
you can use PVC.... Even On common power vented units they use fernco no hubs to tie the heater into a pvc pipe
I did a Bradford *********** vent today with the fernco clamps and pvc 
so really I dont see an issue with connecting to that SS vent with a 3x2 fernco .

no reason to tear the roof apart when this would work just fine......


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## Debo22 (Feb 15, 2015)

skoronesa said:


> No, it's okay, he has a magic non-condensing condensing-gas boiler.
> 
> I still want to know where the current drain goes, probably just into the grass.


The existing drain is over a brick patio step. This picture shows a little more of the patio. Existing water is from rain not condensation


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## Debo22 (Feb 15, 2015)

Plumbus said:


> If you can remove the roof flashing, making the penetration a little bigger to fit 3" plastic shouldn't be too much of a task.
> Since I believe you are in Southern Calif (CPC), you are kind of stuck on the condensate discharge. Is that a laundry room in the pic? If so, and there is a sink, you might be able to run the drain into a y branch.


Current location is in the garage, just to the right of the heater is the door leading to the house.


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## Debo22 (Feb 15, 2015)

Master Mark said:


> looks to me like the condensation drain goes out the side of the house.
> might as well send it to the same location......
> 
> I know that this it probably going to bring screaming howls from everyone but
> ...


I usually install Navien tankless heaters but those dump a lot of condensation.


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## ShtRnsdownhill (Jan 13, 2016)

the takagi units I install can be vented and have the fresh air both come in through the side of the house, as long as no doors or windows within the proper distance...


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## plumbstar (May 4, 2018)

Try a Noritz NR98SV


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## breplum (Mar 21, 2009)

I know you said non condensing, but why not just drill out a hole into the patio and run condensate down the hole?


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## skoronesa (Oct 27, 2015)

breplum said:


> I know you said non condensing, but why not just drill out a hole into the patio and run condensate down the hole?


It's getting inspected.


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## breplum (Mar 21, 2009)

As long as condensate goes into soil, we are not prohibited from using any available location.
If you need gravel, you could core out a sleeve of soil and pour gravel in the void.


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## Nazareth (Sep 30, 2017)

Where are you planning on running the TNP?


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