On Mon, 14 Mar 2011 17:06:33 -0500, Jim Yanik
wrote:

"RBM" wrote in :


"Aaron FIsher" wrote in message
...
I bought a home a few months ago and didn't even think to look at the
hot
water heaters.

A friend suggested today that I set the temperatures differentially;
and when I asked why, I realized I had no idea why or to what
advantage two hot water heaters would be set up in serial
connections. (I'd have used one for the teen's bathroom, and another,
in parallel, for the rest of the house.)

Anyway, what's the THEORY and RATIONALE for having two hot water
heaters in parallel?

Specifically:
- What's the main advantage (is is simply gallonage?)
- What is the main benefit?
- What is the key drawbacks?
And, most importantly:
- Would you set the temperatures differently on them or the same?

More hot water because of the double volume, and faster recovery
because you have double (whatever is heating them)




the hot water from #1 heater going into the second heater (in
series)doesn't get heated unless it's temp is lower than what the
thermostat is set at.
and available volume or flow rate doesn't increase,because a tank can only
flow so much water,and that flow has to go thru the 2nd tank.

a parallel connection allows both tanks to add to the water supply(double
flow) and both tanks do the heating.

I doubt a series connection would pass inspection.
It is not that uncommon, so MUST pass inspection. It uses the same
theory as the dual element electric water heater, where the bottom
element heats the cold water that comes from the mains or well, and
the top element heats the warmed water. It will more than double the
amount of hot water available.