Problem with boiler

[MarkR]

I live in an apartment and have a problem with my boiler.
The water in my boiler seems to be boiling up even though I don't have the immersion turned on.
This results in very loud banging noises from the pipes leading from the boiler tank to the overflow tank in the upper floor of the apartment building. The pipes sound like they are going to explode!
Furthermore, there is boiling water coming from my cold water tap.

Has anyone had a similar problems or know of a solution or professional to contact?

Thanks.

 

[beldin]

Something is heating the water. The hot water in the boiler tank is rising and going into the overflow tank upstairs. This is dangerous as that tank could rupture with the hot water in it.
Is there a gas boiler coming on. Or the immersion is coming on and overheating.
A plumber is needed.

 

[Towger]

As per Beldin, this happened to a relative last year. The immersion thermostat failed and boiled the hot water cylinder, which over flowed back in the cold water tank (as it should). The only problem was a new cold tank was added the year before and the lazy plumber did not bother to change the hot water over flow pipe to the new tank. The result end result was a new ceiling.!