BOILER STAYS ON AFTER TIMER ENDS?

Hi all,

Please someone guide me!

When my timer on my boilers ends (eg. 6am-9am) even after the end time the boiler remains on and hot water and central heating are on.

Does anyone know what is wrong.

I had a plumber change my timer, which still didn't solve the problem.

Please help!!
Update: have tried the on off button at the mains. it switches the boiler off and on! but the timer still won't work, it will not turn off it self when the time runs out....
Update 2: thank you for you response... it's not a combi boiler. Still no joy? any other? thank you.
6 answers 6