Hi I've been having same probs got new boiler just over 2 yrs go couldn't get water or central heating. Just got someone out to be told this part not covered and its prob with the timer cost approx 45-50 pounds. Just check your Honeywell code, they easy to get off and bk on just mje sure you turn off cos wires are live. If you have a tank like me I have 2 valves upstairs one for heat n one for water if these are on automatic just change to manual (push levers over and it will work for now) these Honeywell timers are a real problem so I been told. Hope this helps you and saves you call out charges these ppl charge.