by ericmark »
Tue Nov 04, 2008 10:52 am
Most timers require 6 wires (including earth) but have 7 connections. These will normally come from mains supply and go to the room thermostat and tank thermostat often via a junction box.
The problem your likely to have is wires in walls. There are permitted zones and these are defined by where visible electric boxes are mounted so if you remove a switch, socket, timer, thermostat etc. You will also have to remove the cables.
As a result my old timer is still on the wall although set to 24/7 on as the thermostat now has a timer built in and instead of switching on and off it changes the temperature according to time of day.
Honeywell site now requires registration up to a few months ago it was open access but they produce a special junction box to join all the cables. But many builders have not used these and use a socket box with connector strip.
As a result tracing the wires of a central heating system can be a nightmare.
As to colour codes only the wires out of the motorised valve are set colours the interconnecting cables if your lucky may be numbered but more likely to be red, yellow and blue in any order.
I tried to help someone before and
http://www.ericpalmer.fsnet.co.uk/Centr ... ating.html may also help you.
As to buying wire if it is to be buried then Ali-tube may be best as it does not require RCD protection but as to number of cores you will likely find any thing other than triple and earth expensive and hard to source in short lengths and using a role of triple and earth and running two cables where required may be only option.
As most central heating is supplied from a switched fused connection unit with a 5 amp fuse even 1mm cable will take this current.
I would think twice about moving it can be a nightmare. If you do be very careful taking notes of what goes where. I would suggest taking photos before you start to remove any cables so if you do make a mistake you have something to refer back to.
Except when using off peak power can’t see point in timer on hot water we lag our tanks now, and as I said Horstmann DRT2 thermostats and the like make timers on central heating redundant so if you don’t need to access does it still need moving?
Eric