Folks,
Just to let you know that, thanks to your valuable advice, I have now
replaced the old thermostat with the 907. For the benefit of anyone
contemplating to do the same, here is the process I followed:
I switched off the boiler at its fused switch and removed that fuse. I
checked it was below 8A. I then removed the external casing of the old
thermostat and tested that there was no voltage down to 10V AC at the
terminals. Although it's pretty standard, I noted which colour wire
corresponded to which type (Live, Neutral, Switched-Live), then
disconnected them from the old thermostat and dropped its base.
At this stage I only had three wires and the box on the wall. I
isolated Neutral using a connector, then wrapping the connector with
electrical tape. (My initial intention was to use heat-shrink sleeve,
but I could not readily source it.) I screwed the base of the 907 on
the wall, then connected the Live to terminal A, and Switched-Live to
terminal B of the base, as per the instructions. The rest was as per
instructions. I switched on the boiler at its fused box, then tested
that the thermostat drives the boiler (actually I think it drives the
pump in my case, but never mind) on and off.
I like the new thermostat and am well pleased that I did it myself, if
I may say so :-)
With a little help from my friends, that is! Thanks again.
Kostas
On Mon, 22 Oct 2007, Kostas Kavoussanakis wrote:
Hi,
I would like to replace my old (80s) Honeywell room thermostat with the 907.
It's a very common model.
On the old thermostat there are 5 terminals (top to bottom): 5 2 3 4 1. Of
these, 2 (Neutral), 3 (Switch Live) and 1 (Live) are connected.
I understand that the 907 only accepts two wires.
Is my installation compatible with the 907? The installation manual suggests
current needs to by 8A; how does one check that?
http://europe.hbc.honeywell.com/prod...7uk07r0906.pdf
Am I right that this a DIY job? I know I need to switch the boiler off at the
mains and drop the fuse while the wife and kids are out shopping :-)
Thanks,
Kostas