On Fri, 03 Nov 2006 06:43:23 -0800, Mathew Newton wrote:


VisionSet wrote:
visionset wrote:
I've got 22 between boiler and upstairs and downstairs and upper and lower
circuits T'd off in 15. With such a system and my new combi it seems there
is little need to balance....

Comments? I was a little suprised.

--
Mike W

I'd be interested to hear some too - my system (12 radiators (11 TRV'd)
on a combi-powered sealed system) is currently unbalanced. Or, perhaps
more accurately, all the lockshields are fully open.

Every radiator works well and heats up at the same rate... so would I
still benefit from 'proper' balancing? Perhaps my feed/turn temperature
differential is potentially 'sub-optimal'?

Mathew

The purpose of TRVs is mainly to prevent certain areas becoming
over-heated. They have the fringe benefit that, eventually, provided the
system is adequately powered, the system will be balanced even if it
wasn't beforehand.

Ideally the system should be balanced initially with the valves off (or
set to max).

Many combi models simply have a standard 3-speed pump motor set to max.
The better models and more recent models tend to have the pump speed
adjusted by the boiler's controls. This means that as the required output
power falls the pump power can be reduced. The effect is to greatly reduce
whistling. Different models seem to be more or less prone to whistling and
amazingly the market leader is, IME, one of the worst.

Setting a lower pump speed on many combis will simply reduce the HW
production rate.

Removing all the TRVs is against the spirit of the building regs if not
the letter.

HTH

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html
Gas Fitting Standards Docs he http://www.makewrite.demon.co.uk/GasFittingStandards