On Thu, 18 Dec 2003 01:12:12 +0000, The Natural Philosopher wrote:

Ed Sirett wrote:

On Wed, 17 Dec 2003 13:00:05 +0000, Christian McArdle wrote:


I think I missed the point about the master switch ;-) Sounds a bit like
overkill as the two zone programmers can be co-located anyway.

Co-location is impossible. They are programmable room thermostats. They
won't sense the right temperature if they are in the wrong room. I suppose
you could use a multi-channel programmer and straight room stats. However,
this would cause many disadvantages. Firstly, this system doesn't allow
different temperatures at different times of day. Secondly, manual override
(i.e. boost/advance) buttons will be in a dark cupboard under the sink with
bottles of bleach in the way, rather than on a convenient well lit nearby
wall.


I agree the idea of a master switch is well useful for maintenance if
nothing else.




I am pretty sure its mandatory - my whole heatng system is run off a big
switched fused spur with its own neon and switch bang next door to the
controller and very near the boiler. I thought you had to do this with
all boilers extractor fans etc etc.

I am not suggesting that the programmer replaces proper DP isolation.
I'm talking about, say, you want to diagnose the boiler, you are testing it
out live but want to be sure you don't have a CH demand only a HW one.



--
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