TT wrote:

"larry moe 'n curly" wrote in message
oups.com...

I need to replace a really old electric solar water heater
in a domestic hot water system, and I'll buy a conventional
electric heater because solar tanks cost much more but are
of inferior quality.

Conventional heaters are usually modified for solar use by
shortening the dip tube in half and using it as the inlet
for the solar-heated water, and the drain opening replaces
the normal dip tube for cold water But I found this diagram:

www.solardev.com/images/ho****er_r2_c1.gif

which shows an unmodified conventional tank being used for
solar heating. Instead of feeding the solar-heated water
into the middle of the tank, in this diagram it goes into
the bottom. Will that work well?

Honestly, if your solar collector system & pump are really
old you might as well just cap the solar collector off and
put a conventional water heater in. I just did that in my
home when the solar water heater went out. I spoke to
several solar water heating experts and they basically
said my old solar system (late 70's early 80's mfg. date)
was useless.

The solar collectors are as good as new (glass, copper, and aluminum),
the pump still works fine (changed impeller, shaft, and seal), and in
the warmer months the electric backup heat hardly runs at all. I have
enough valves installed to let the solar part be bypassed easily, but
that would mean spending at least $100 more in electricity.
Why did those experts say that your old system was useless?