biasi m90e 24s

Hi, I have a biasi boiler. Normally it works fine however no hot water after running it for 20-30 mins. The next time i turn the tap on, its cold. I have to wait for 5-10 minutes before it works again. No lockout. No indicators. Only indicator it gives is fast light pulses when it can't turn...

I would be very grateful for any help or advice on the following. About 3 weeks ago the boiler stopped igniting when a tap was turned on. To get hot water I just switched on the central heating. Or if the central heating was set to auto and already running we got hot water out of the tap on...