Upgrading central heating programmer

[tsc]

I want to replace my existing electro-mechanical Horstmann Diadem 425 hot water and central heating programmer with the more modern Horstmann Channel Plus XL H21 electronic programmer. Will I have to do any rewiring or will it be a straightforward shoe-in substitution? Horstmann says the backplates are compatible.

Steve

[Rob Summers]

You might need to move a wire or two but the details are in the instructions or here:

[tsc]

Thanks, Rob, those instructions allow me to check current against new positions for wiring, should any be needed.

Steve