Converting from Tank to Condensing Tankless

[Josh342]

Hello everyone..

I have a Rheem water heater that was installed in 2004. I've owned the house since 2020. My water heater is leaking from underneath and I would like to replace it with a Takagi condensing tankless. While looking at the user guide from Supplyhouse, I find that it says I can install the intake at the unit and run at a minimum of 2" vent PVC out of the house as long as I am working with 1 90 degree bend. If this is so, could I simply use a 2" pvc and go straight out the house? If yes, does it need to have a 45 at the end? Should it have a screen? Or should this pipe come out and bend upwards and have a straight up going horizontal with another bend at top? I try to research online but finding a lot of conflicting information. Would I be better off using a PNC Concentric tube?

Thanks..

 

[Breplum]

Combustion air is always a factor on the intake side. If snow is an issue, then stub above snow level. It can always be vertical in most of California, but often people use 90 or 90 plus 45 down. PVC screen comes with all condensing WHs I buy, but haven't bought a Takagi condensing.
Navien condensing NPE A series can run 60 ft plus many 90s and has built in insulated mini-tank that keeps water always hot.
Be aware that most tankless installs will require full upsizing or dedicated pipe to provide proper operation...you cannot typically just use what is there.

 

[Sponsor]

 

[Fitter30]

Have to know what.your coldest water temp is, max gpm hot flow needed and gas line size after choosing the heater. Outside air makes the heater more efficient.

 

[John Gayewski]

My opinion is you shouldn't buy a takagi. They are junk. That's my experience anyway.

 

[Josh342]

Combustion air is always a factor on the intake side. If snow is an issue, then stub above snow level. It can always be vertical in most of California, but often people use 90 or 90 plus 45 down. PVC screen comes with all condensing WHs I buy, but haven't bought a Takagi condensing.
Navien condensing NPE A series can run 60 ft plus many 90s and has built in insulated mini-tank that keeps water always hot.
Be aware that most tankless installs will require full upsizing or dedicated pipe to provide proper operation...you cannot typically just use what is there.

When you say 'dedicated pipe', are you referring to the gas supply?

 

[Josh342]

Have to know what.your coldest water temp is, max gpm hot flow needed and gas line size after choosing the heater. Outside air makes the heater more efficient.

I have city water and unsure what my coldest temp would be or how to find out.

 

[Josh342]

My opinion is you shouldn't buy a takagi. They are junk. That's my experience anyway.

I have read some people having issues with the Takagi but I also read people having issues with a lot of other brands as well. I am not sold or partial to Takagi. I just know they exist.

What do you think of Rinnai?

https://www.supplyhouse.com/Rinnai-RUCS65IN-RUCS65IN-130000-BTU-Condensing-Indoor-Tankless-Water-Heater-Natural-Gas

 

[Fitter30]

I have city water and unsure what my coldest temp would be or how to find out.

Call your water company. Back in 2014 Manistee frost line hit 72" according to Ludington paper.

 

[FranZ28]

Funny our takagi just started leaking tore into it just a hot mess water took out solenoids and wiring...