[b]My central heating system won't turn on or off with the timer. The valve has been replaced, and the cylinder thermostat replaced. Heating/water only works when the main power switch is turned on/off manually.The timer switch is working but not communicating witht the heating system? Any ideas? :?:
IF the boiler always fires when the timer is in the off position, then either the timer itself is faulty, or a frost stat is set too high (or it's doing what it's supposed to if the boiler is in an outhouse or garage etc).