How do i find out the model of my Landis and Gyr heating timer,?

I'm guessing it's the mechanical rwb programmer (old mechanical)
Something akin to the one on this link:

http://media.diynot.com/118000_117104_8874_40701032_thumb.jpg

No batteries are available for this as it doesn't use them.
Replacements are many and varied, it has an industry standard backplate so many others clip straight on (two screws underneath), and use the same wiring configuration.

I generally use a Drayton as a replacement, the link shows the programmer, I'm not suggesting using this merchant or any other, try searching.

http://www.heatingcontrolsonline.co.uk/acl-drayton-invensys-lifestyle-lp241-24hr-programmer-p-105.html

Carefree
July 2010