Multiple Water Heater Hook Up

[dripdrop]

hi. i have a commercial establishment that requires additional BTU's.

my plumber has the following design:
- use 2 water heaters; 40 gallon & 65 gallon
- each water heater to service 2 different "zones"
- main water line comes in and 'T's' off to each water heater
- hot and cold water supply lines from 40 gallon water heater goes to zone 1
- hot and cold water supply lines from 65 gallon water heater goes to zone 2

please review diagram attached and let me know if this is a feasible solution.
thanks again!

[Towers Plumbing]

Not sure what your distances are but you might consider a 50G 50K BTU or 60/60 to do the same job. Bradford makes a 55 gallon 80k BTU heater that has a 200 gallon for first hour delivery rating. Heaters are more but still might be less than two water heaters and repiping.

[dripdrop]

thanks for the reply towers.

i actually have all the material onsite. i'm more concerned with the design illustrated in my original post. will this design work?
thanks again!

[leejosepho]

- main water line comes in and 'T's' off to each water heater
- hot ... from 40 gallon water heater goes to zone 1
- hot ... from 65 gallon water heater goes to zone 2

Each zone should get hot water if the line supplying the heaters is sufficient and if the main line that also supplies cold water to each zone is sufficient. But in my own case, our water heater is somehow the last to be supplied and we end up with little hot water in the bathroom whenever water is being demanded anywhere else.

[dripdrop]

so will the design i have in the drawing work and pass code?

[hj]

It is a "no brainer". Give BOTH zones the maximum BTUs. Connect the two zones together, then pipe the cold water into one of the heaters, it is immaterial which one, then the hot of that heater to the inlet of the other one, and finally the outlet of that heater to the connection to both zones. This way you do not have to worry about either zone needing more hot water than ITS heater could supply. The only possible downside, is that if the zones require different water temperatures, then you use a temperature control mixing valve on the zone requiring lower temperatures.

[MACPLUMB 777]

Take HJ'S plan but use the same size water heaters and plumb them both cold water in
and hot water out this gives you maximum btu's and tank storage plus if one goes down
you can bypass it and still get by on the other heater
this is per ALL Mfg's install specifications !
PHD IN WATER HEATEROLGY
LICENSED SERVICE AGENT FOR ALL BRANDS

[hj]

In "parallel" works as long as you can convince the cold water to flow through both of them equally. That ONLY happens when the flow rate is high enough so that it has to flow through both. In "series" the water ALWAYS has to flow through both and it makes no difference if the heaters are the same or not. Two ball valves and two "3 way valves" can isolate series heaters, (Doing it with parallel installations requires four ball valves), and the first one will usually fail first so you make it the cheapest one of the pair. With parallel, when one fails, the replacement will NEVER have the same dynamics as the remaining heater so it will disrupt the supposed equal flow, unless you replace both of them at the same time.