using the boiler there is a loud screaming noise the fan is on all the time and have to turn it off from the main switch the boiler is saunier duval thelia 23

Tina, October 2008

Hi Tina. I'm afraid we don't have the answer but can only share your concerns. My nan has a Saunier duval boiler and it really thumps when the heating is first turned on. the noise can be deafening. None of the engineers she's called has any idea what's going on. We're going to try de-scaling it to see how we get on. Can let you know if you want...

Louise, November 2008