"IMM" wrote in message
...

"Jonathan" wrote in message
...
Hi All,

Just reading the FAQ on central heating at
http://www.cucumber.demon.co.uk/diy_test/Q2.12.html

It says "After installation and commissioning, a new central heating
system
should be balanced." And says: The "...aim of balancing is to achieve
the
correct temperature drop across the boiler flow & return pipes (11°C)."

I assume that in layman's terms this means, "... so that the water that
goes
back to the boiler is cold enough to need re-heating, yet warm enough to
have delivered sufficient heat to the last radiator in the chain? Is
that
right?

Sorry if this is a stupid question...

Jonathan

Install a micro-bore system with manifolds. They are self balancing if
the
rads are sized reasonably correct. Then install an auto variable speed
Grundfos Alpha pump.

Best is a heat bank with the CH manifolds taken off the bottom of the
cylinder. The boiler will be self balancing and so will the rads. A win,
win situation all around in DHW response, commissioning and simplicity.

Just to add:

Plumbing Mechanical Service Book 2, a NVQ plumbing book. This is not a DIY
book so please don't buy. It has a section on heating, and a sub section on
Mini-bore on page 170. It says:

"If the manifolds can be situated in such a way that the branch flow and
return to each radiator is approximately the same length, the frictional
resistance will also be approx the same, making the system self balancing".

And on page 171:

"In a well-designed system balancing should not be necessary as the aim is
to keep all pipe runs to heat emitters at, or near, as possible, the same
lengths."

And on page 172, there is a cut-away of a twin entry rad valve without
lockshield adjustment because in properly designed mini-bore systems, which
is easy to do, balancing is not required.




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