On Tue, 12 Oct 2004 19:48:14 +0000, Someone wrote:

Hi,

We have a Baxi Barcelona which according to the blurb has two ways to
connect the pump, one for fully TRV'd systems and the other when used with a
bypass. The fully TRV'd one runs the pump from a separate connection from
the boiler so that the pump shuts off when the boiler does - the other way
being to run it as normal via the timer feed to the boiler.

But running it in this way makes the pump stop when the boiler is not
firing, even when the mains to the boiler is on. Is that normal? I thought
pumps usually ran all the time.

Someone (who ought to have known better in IMHO) decided in the design
that unlike all other modern boilers which have a permanent live and
switched (demand) live connections the BB
would work like an older style boiler with a simple apply-mains-and-it'll-
start design.

The boiler tries to work out when there is little flow and cut the pump
and gas for a while but of course it can't do any pump over-run to remove
excess heat if it stops in full flight.

You can make of this what you will, of course.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at 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