"John Aston" wrote in message
...
"IMM" wrote in message
...

"John Aston" wrote in message
.. .

If anyone else is reading this thread and wants some background
information,
I came across Warmrite's "Manual Of Modern Hydronics" at
http://www.heatinghelp.com/pdfs/156.pdf

It gives loads of examples of different boiler/heating arrangements.

I had a look. The document is specific to UFH and the USA/Canada
variantions
and heavily leans towards the makers solutions. Look at figs. 2.1,
regular
boiler & 2.2, condensing boiler. Condensing biolers should not mix
return
water that woudl raise its temperature. That is why a thermal
store/heat
bank is the best alternative when using a condesning boiler, which is
what
I
have been trying to get you to understand.


Sorry if I've missed the point about a heat store.

I've spoken to technical engineers at Keston, Viessman, MAN Heiztechnik
and
Geminox, and they have all recommended that a low loss header should be
used
for my application. It's difficult to argue against that weight of
opinion.;

These people mainly deal with commercial applications, where headers are the
norm. You intend to use UFH, contact the UFH people and just about everyone
of them will say use a thermal store. So their weight of opinion would be
greater, as there are more of them. Using a header will lower a condensing
boilers efficiency, that is certain. Ask the boiler people about
connecting the boiler to an integrated thermal store with the UFH and rads
taken off the store. Not one will say no.

You also have to take into account that the tech depts have people who read
from crib sheets. Did you ask them about a header specifically? Or did you
ask them about running a UFH and rad system off the boiler?

Look at this:
http://www.heatweb.com/techtips/unde...orheating.html

Then scroll down to Twin Zone Thermal Store Injection System

A dedicated UFH thermal store shown with the old fashioned type of waether
compensation of stats. Cheap and effective. Of course an outsise weather
compensator can be fitted to maintain the UFH section to what the outside
temp dictates.

Rads can be taken off the top of the store.

Also go to:
http://www.heatweb.com
scroll down to underfloor heating and see the solutions to underfloor
heating.