Dual water heaters

[Michael Young]

Checking for current opinions on dual water heaters. Parallel vs series.
Replacing two 40 gal n/g heaters for 4 plex. Currently plumbed in parallel. I've monitored them & one is definately doing most of the work. I'd like to plumb the new ones in series, setting the first one at about 100f and the second at 140f.
Concern is legionella in first tank. What say you?

Rinnai Sensei!! Boom Chicka Wah Wah!
Just DO IT AND NEVER EVER LOOK BACK!

Rinnai Sensei ALL THE WAY.

People who are still heating water in A BIG POT deserve the legionella they get and they can die! die! die! you filthy "tankers"

 

[Dana]

Rinnai Sensei!! Boom Chicka Wah Wah!
Just DO IT AND NEVER EVER LOOK BACK!

Rinnai Sensei ALL THE WAY.

View attachment 52787

People who are still heating water in A BIG POT deserve the legionella they get and they can die! die! die! you filthy "tankers"

For a 4+ bathroom building, I don't think so.

MAYBE two big tankless could cut it (en sus sueños), but that would potentially require a lot of changes to the hot water distribution plumbing in a 4-plex.

 

[Sponsor]

 

[Jm66208]

Thanks for all the input. After searching for answers to this dilemma over several years, I've come to the conclusion that common hot water source servicing four separate units is simply a less than ideal setup. Each unit should have it's own water heater.