its a baxi boiler, timer does heating and water at same time. manual diverter valve upstairs to adjust to more heating/more hot water etc

Combi boiler or Y plan?

well figured out its a faulty timer but wired it into a plug socket now through a plug timer job done :)

If mattk doesnt reply in here might be worth u2'ing him? He is a plumber by trade, whether he does sparky on boilers not sure

Right trying to put a new timer in, but cant get it to work. this is the second timer we have tried now. we have:

Brown
Blue
Black
Earth
(from boiler)

Brown
Blue
Black
Earth
(from fused box)

the black is going straight from the fused box to the boiler so i'm guessing its the permanent live.

if i connect the two browns, and the two blues, it fires up the boiler.

the timer has:

Water On
Heating On
COM
Earth
Neutral
Live

The heating and hot water are on the same system, so it literally needs to be just a switch with a timer on. the timer i have got has a switch that can be either hot water and heating, and heating only. surely if i put the two blues to neutral, one brown to live (from fused spur box) and other brown in heating on, when i switch it to heating only it should fire up boiler when timer is set to on?