Two water heaters in series.

 We moved into our new house last week and used our whirlpool tub for the
first time. Guess what, we ran out of hot water.

We told the builder about the problem and he had a plumber install a 40
gallon electric hot water heater in series with my 48 gallon gas water
heater (builder pick up the cost).  I now get 120 degree hot water into my
AKER (ACC2-6060) 100 gallon whirlpool tube (average operational volume 74
gallon).

My question is:

Is this a good solution?

Will the electric hot water heater cost a lot to operate?  I have a by-pass
valves to both units. There are only two people living in the house that
require hot water.

Any advise?

Thanks Paul

 

by-pass

Your putting hot water into a tank that hot water  is being depleted.  I
have a question, why do you not have a heater especially for the tub? A
heater that would reheat the tub would be a better solution in my opinion.
Like what they use for spas? Probably no one planned for one, oops....
Drawing off hot water from water heater constantly will be a loosing
proposition especially when it is cold. Since you have gas why did they put
in an electric? Probably easier, not. I would have gone for a bigger gas
heater, like an 80.  Gas usually recovers faster than electric. Did you try
pushing up the temp on the gas heater first? It would be worth a try. You
should be able to get 140 ish out of the water heater.  120 is bit hot for
tub, 105-107 is a better temp. I tried my tub at 110 for awhile and passed
out once. Fortunately the wife was watching me carefully and woke me up
before I drowned.  .
A electrical shut off for the electric heater, like a timer will allow you
to heat when you need it and not other wise.
Guessing for your area of the world, gas is cheaper to heat with than
electricity. It is here.

can you insulate the tub?  can you insulate the hot water pipes? either or
both will help

congrats on the tub, I use mine frequently

 

SQLit wrote:

SQLit has some good points.  The tub should have its own
heater.  The larger question is how often do you use the
tub?  So will you be operating the hot water heater a lot?

I don't understand your bypass valves?  why do you need
bypass valve? You should only need additional valves if the
tanks are hooked in parallel.  If you plan to use only one
hot water tank most of the time, then put it downstream in
the series condtion.  E.g., if gas is cheaper put it
downstream and only turn on the electric tank about 6 hours
before you plan to fill the tub, then turn the electricity
off when you don't plan to use it.  If the electricity is
cheaper then put it downstream and turn the gas thermostat
down as low as possible.  If they really are in parallel,
which will work ok, all you need is an inlet valve on each
tank and then turn the inlet valve off on the tank you don't
want to use, water won't pass through that tank.

 Have you ever thought about a tankless water heater

Irene and Paul wrote:

 it will work Ok the quick answer was probably that you didn't have enough
flue size to do a second gas heater.  depending on the cost of natural gas
the electric may not be too bad there should be energy stickers on both to
give you an idea of efficiency.  You may want to wrap the heaters but that
is another thread entirely!

You defiantly needed 2 heaters.  instant ones also require lots of intake
air as well as flue due to high BTUs.
make sure the second tank and first are set for about the same temp. If the
electric is second and electricity cost a bunch more you could kick the gas
temp a little higher making the electric a little less likely to heat.  If
the electric is cheaper due to gas cost (here in Colorado it just jumped
70%)  then you could lower the gas temp a little bit and let the electric
heat the water a bit!

you can get a timer for the electric to turn the heater on and off so if you
knew you were going to use it at a certain time of day you could bypass it
and have it turn down.  I guess the next step would be to get a solenoid
installed on the valve so you could open and close it from upstairs!


Wayne



by-pass