Top Cistern becoming too hot - No hot water in pipes

I have pulsaciol III in my flat. Yesterday suddenly there are some rumbling sounds from the cylinder and then no more hot water came from the taps. I thought there might be need to fill in water in cistern, but cool water that I filled in became boiling hot with in few minutes. I replaced this water and again poured cool water but they again became hot with in no time. I am not able to understand the problem. No hot water from taps but water poured in cistern becoming hot in no time. Can anybody advice me what might be the problem and how to fix it.

Could be a blocked cold feed.
Are you getting water from the hot taps? Even cold ?
Over heat stat needs checking too.
Have you the book on your unit?
If not down load one for free at Gledhill website.
Sounds as if you may have more than one problem.
You may find some one in your area if you look on the home page.
List of advertisers. If not Google one up for your area.
Mike
MGC/H2O
Norfolk.

Hi Mike, Thanks for your response.
Even the water from hot taps is cold. I will try to contact some one in my area.

You really need to arrange for an engineer in this case. The problems could be relating to the Sensors, PCB, Pump or mixing valve. Whatever the case, an on-site test will need to be carried out.