On Tue, 01 Apr 2008 14:10:31 +0100, David Hansen wrote:

On Tue, 1 Apr 2008 04:52:39 -0700 (PDT) someone who may be tvmo
wrote this:-

Are sealed systems better than open systems?

It depends.

To a certain extent. There are only a few reasons I can think of a

1) The existing system is correctly working and setup correctly and the
new boiler would require additional expenditure to add the sealed
components.

2) The existing system has radiators which are so old the designs can't
take the pressure.

3) The existing system has massive 'period' radiators which have such a
huge volume of primary water that a seal system would be impractical.
In this case I'd recommend that the technology levels are so different
that the new boiler is coupled to the old radiators via a heat exchanger
and athe primary is pressurized whilst the secondary circuit is open
vented.


--
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