New Tankless Venting Question

[Steve Soldo]

Back house has an indoor located Bosch Aquastar that died. Never really worked that well anyway. So I need to replace it. Need a smaller unit, as there are only 2 sinks and one shower.

The water and gas hookups are easy. This will need to be wired, and that is not difficult either. There is no drain nearby, so I will need a noncondensing unit.

I really like the Navien units, have one in my main house. Problem is that all of the Navien noncondensing units have concentric venting.

Question: Is it feasible to "upgrade" the existing standard 5 inch venting to concentric venting without doing a lot of construction? Alternatively, I will have to choose another vendor with a separate air intake. What vendors would be recommended.

 

[Breplum]

Your pressure release on water heater has to go to the outside, so condensing drain to outside is the way to go.
I wouldn't touch concertric again ever, waste of money for poor effeciency gas compared to 96% condensing...and PVC vent