On Wed, 14 Jan 2004 10:54:05 -0000, "Christian McArdle"
wrote:

Are there any pitfalls I haven't thought of?

Firstly, use a 2 channel programmer and wire the new programmable stat
through the CH side.

Why use a programmable room stat if there is already a 2 channel
programmer, surely a standard wireless stat will suffice.

There is almost no difference in price. You don't use
the programmer for actual timing, but it is very useful as a central
location to turn everything off and on without having to traipse round to
the room stat.

The spur that turns off the heating could quite easily do that. And it
is unlikely anyone will have to traipse round to find the room stat,
surely it would be where you screwed it on the wall?

The CH side is usually set to 24H (or Off). It is
particularly useful if you have multiple heating zones,

Which there aren't as there are only 2 valves, so that would be an S
plan then.

or your room stat
doesn't have a simple "Off" feature, as many don't.

Secondly, ensure that you have a cylinder thermostat. It sounds like you
have an S plan system. If no cylinder stat is present, you need to insert it
in series between the programmer "HW On" output and the hot water zone valve
motor live (normally brown) wire.




SJW
A.C.S. Ltd.