I am planning to install 2 HW heaters in series with bypass valves. I would like to confirm the proper valve settings when running in 4 different scenario's. The Heaters are labeled HW Heater 2 and HW Heater 3. There is no HW heater 1. The valves are labelled Valve1 thru Valve6.

Normal operation - Valve 1 & 2 Closed Valve 3,4,5,6 Open for a) & b) below

a) To run with 2 hot water heaters in series -- Run as depicted in Figure 34
b) To run with HW heater 2 only -- turn off circuit breaker to HW heater 3
c) To run only HW heater 2 only and remove HW heater 3 -- open VALVE 2, close VALVE 5 and 6. turn off HW3
d) To run only HW heater 3 only and remove HW heater 2 -- open VALVE 1, close VALVE 3 and 4. turn off HW2


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I hope the link above works its my first time

I am planning on running only 2 months with both water heaters and the other 10 months with HotWater Heater 2 only. the bypass would be used only for repair/replacement of WH.

Thanks
Tom

Are these gas or elec water heaters? You mention a circuit breaker in your comment but the drawing shows the water heaters to have burners?? If they are gas I'd change the instructions to "shut off gas supply" in place of turning off the circuit breaker to whichever WH you are shutting down or removing for maint.

Otherwise your various modes of operation and which valves to open & close looks ok to me.


I'm posting your drawing here to make it easier for everyone to see:





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with that set-up, you can run either, neither or both.
only thing i would chaange would be to raise the location of valves 4 and 6 so they are above the top of the heaters like 3 and 5..

raise location of valves 4 & 6 to make removal of WH easier?



Edited 2 times.

The location of both hot and cold water for my units are actually on the top of the tank.. This is the only diagram I could find with series and bypass but it shows the cold water going in on the side/bottom of the tank..

I hope the cold water doesn't need to go to the side/bottom of the tank for some reason does it????

Can someone(packy/stuckinlodi) confirm it does/doesn't need to be on the side/bottom

The units are rheem PROE38 S2 RH95B electric

Thanks for all of your help
Tom



Edited 3 times.

The heaters are both rheem PROE38 S2 RH95B see below

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Electric or gas, inlets on top or side, it is all immaterial. the placement of the valves in the piping, NOT their locations relative to the top of the heater are the only factors that count.

It's possible that having the cold water come in at the bottom of the tank will help to keep the cold & hot water inside the tank from intermingling, in case the diptube is not adequate or broken. Also, having the cold water flow into the bottom of the tank would help to keep the tank drain line open better, in case your area has a problem with hard water and that lime stuff settles to the bottom of the tank.

massachusetts code says the cold inlet valve must be 6 inches higher than the top of the tank.
it has to do with servicing the valve (think old days with washer type stem) and not having to drain down the tank below the level of the valve.

understood, that makes sense for what they had in those days, and the code is not likely to change anytime soon. I forget that sometimes when something doesn't have a clear reason to be a certain way it is often due to the code.

Most modern heaters are "self cleaning" with a dip tube the keeps the sediment stirred up.