Whistling Bolier

[GC812]

Hello - hope you can help me. I have a Potterton Suprima 50 boiler that has recently developed a strange whistling noise.
The noise starts about 10 minutes after the boiler fires up and then continues for about 15 minutes when it goes quite. If the boiler is on for a while, it may happen again a couple of hours later.
My local plumber has been twice and basically given up so any advice would be appreciated.
Thanks in advance.

 

[breezer]

try a heating engineer

 

[TheIce_Man]

How old is the boiler, it sounds like it is scaled up or beginning to even boilers that are only a few years old can scale up due to where you live and the quality of the water in the area, you could try bunging it some boiler noise silencer into one of the rads and let it circulate.Could also be a faulty gas valve, if the noise alters when you give the gas valve a clout then it is definate.

 

[GC812]

Boiler is probably 8-9 years old but just about every part has been swapped at some point - its been nothing but trouble.
Also over the weekend, I noticed that the radiators were still getting hot even though the hot water only option had been selected. Is this connected?

 

[Igorian]

The latter sounds like a defective diverter valve or actuator.