On Sun, 31 Aug 2008 14:23:45 +0100, John wrote:

A friend (as in the Flue question) has had a combi fitted upstairs (new
flue through roof). The fitter did a great job, but the electrician
needs to come in 2 weeks after my friend returns from holiday -
therefore it is running without a room stat at present.

He is concerned about the noise and some of his family have switched it
off at the spur unit. My instinct is that this is a bad idea as it could
upset the pump or fan control. However, what is the noise - is it a fan?

There are two sources of noise the combustion fan and the circulator.
When on standby these may operate.

Most modern boilers seem to have an anti pump seize feature. Some pumps
when they get older can seize up if they are left for several months.
Once a day is probably OTT to ensure that the pump does not seize but
IMHO it must add some reliability. Older systems where the pump is only
used for the CH did have a habit of seizing over the summer.

However the most likely cause of significant noises from a combi when not
in use is some sort of warm standby mode. It might also be that the
customer has not been fully informed about the way the boiler works
etc.etc. And are inclined to believe that off should mean off and are
thus concerned about the noises.


I'm unaware if any boiler has an anti seize feature for the combustion
fan, these rarely seize, in my experience, anyway, so far.

In general the only boiler that I know of made in the last 15 years which
was intended not to be connected to the mains 24/7 was spit the baxi
barceona. A number of features require permanent power

Frost Protection
Built in time clocks.
Anti seize feature.
Warm stand by feature.




--
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