Strange boiler problem

[estivator]

I hope someone can help. I have an Ariston Euro Combi boiler which works fine when the timer control switch is in the permenantly on position, but not when the timer switch is off. It means that I don't get hot water unless I turn the timer on. This problem just started recently and the boiler has been serviced within the last 4 months.
Thanks in advance.

 

[nickso]

not really familiar with your boiler but that kind of behaviour is usually the diaphragm.

im sure someone who knows your boiler can confirm or suggest something else