loud screaming noise from boiler

[jonesy76]

hi there I have Worcester bosch 28cdi that has no heating and when I run the hot water theres a loud screaming noise coming from the boiler any clues would b appreciated

 

[Scott_D]

Is the pressure in the heating system?
Best not to use it or you may damage it further

 

[jonesy76]

theres pressure in the boiler and he's getting hot water but when he turns the tap on there s a loud noise from boiler it was at a friends house im a plumber but not gas safe so ive just turned it off and told him to call someone out just curious to what it might be

 

[SimonG]

Theres only one thing on a boiler that tends to scream.

 

[jonesy76]

I feel a joke coming on here?lol

 

[SimonG]

The cust when you give them the bill