On Tue, 23 Oct 2007, Roger Mills wrote:

In an earlier contribution to this discussion,
Kostas Kavoussanakis wrote:

Thank you John and Roger for the quick answer.


Thanks for your concern; what's uncertain about dropping the fuse? :-)
Sure, I will check for current at the terminals as well, isn't that
standard?

You *should* have an FCU (fused connection unit) which feeds the whole of
the heating system. Turning that off will isolate the heating system without
affecting anything else in the house.

Yes, that's the fuse I intend to drop out of its housing, so as to
also check its rating; if it's under 8 I am laughing.

But it's always a good idea to check
for *voltage* on anything you're likely to touch, even when you think you've
isolated it. You'll need a voltmeter with a 300v AC range for this - don't
rely on neon screwdrivers!

Thanks for this, I was indeed planning to check with a filament (I
think it is) screwdriver.

identical to the old one. A common problem is that some people feel
compelled to connect the old neutral wire to something - and end up
connecting it to the only spare terminal, which is 'Heating Satisfied' (C in
your case). The result is that when the house gets up to temperature and the
stat switches, they then have a dead short between live and neutral -
causing a loud, potentially expensive, bang!

Noted, this was made clear to me.

Have a look at
http://www.planningportal.gov.uk/upl...F_ADP_2006.pdf If you can
wade through the treacle, you can probably find evidence to support the view
that changing a stat is *not* notifiable. [I wasn't sure when I posted
earlier, but it looks fairly safe from that document].

Thanks, I have a friendly local spark whom I can ask as well (not the
one who gave me the 70 quid quote :-)).

Kostas