On Sat, 30 Jul 2005 15:28:24 -0500, "Chris
wrote:

My CH system and Immersion hot water system uses two tanks. One tank is
directly above a solid fuel stove that feeds the indirect heating coil. This
tank does NOT have an immersion heater fitted. The base height of this tank
is about 2.5 meters above the ground. My seconf hot water tank is under the
stairs and at ground level. This tank IS fitted with an immesion. The
distance between the two tanks is about 30 foot as the pipe flies.

These two tanks are connected together by two pipes and I've fitted a
transfer pump in the loop so that in the winter when I have the fire going
full blast I can have one bath from the water provided by the immersion
heater and then turn the pump on for ten minutes to transfer the water from
the FIRE tank to the IMMERSION tank and let others have a bath quicker.

A slight problem occurs in the summer when the fire is let to go out and
there is only cold water in the upper FIRE tank. The hot water from the
lower IMMERSION tank now percolates its way to the higher, colder tank.
Heating it aswell.

It is impossible to set the two tanks at the same hydrostatic height in
order to stop this natural transfer.

Any ideas Guys?



First of all, with this somewhat unusual arrangement, hopefully you
have made sure that there is a clear vent path from both cylinders to
the feed/expansion tank. This should be an individual one from each
and anything else that you add should not block this in any way.

I can think of two solutions:

- A zone valve arranged in series with the pump and powered by the
same supply. When you turn on the pump, the valve opens as well.

- A swing check valve in series with the pump. It remains closed
unless the flow from the pump opens it. Convection would not be
enough.

http://www.bes.ltd.uk/products/098.asp




--

..andy

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