My cousin's ancient Potterton CH/HW Programmer has become intermittent and I needed a low-tech replacement.
A Honeywell ST699 was similar in user controls to the Potterton one, so obtained one.
I am a little surprised that although according to the instructions it can be surface mounted, when doing so the rear of the exposed live (mains) terminals are only about 6mm away from whatever it is mounted on.
http://ancient-mariner.co.uk/public/Honeywell-ST699.JPG shows the rear of the programmer. I will be mounting it on a pattress box. Strangely they supply an insulating fibre plate to cover the terminal screws once installed. On other programmers, these screws would not have this added protection. Pity that this insulating sheet will not fit beneath - between the underside of the terminals and the wall/mounting surface.
Clive
