Dear All (and definately one for TomPlum), I have the above boiler and while is works a treat, it has become very noisy! I am not sure what to do, or indeed whether draining the entire system will clear the noise? Once you put on the central heating, all radiators get hot, upstairs and downstairs. The heat in the radiators constant, i.e. top and bottom of the radiator is the same temperature indicating little or no sluge, or trapped air? However, when you turn on the central heating, the boiler turns on, and inside the window you can see a blue/orange flame however, within 45-60seconds later, the boiler makes a wheezy/grinding noise which progressively has got worse and now quite loud! Furthermore, over the last 6-months or so, I have observed that once the heating has been on for about 1hr or so, there is large whooshing sound which travels within the pipe work - that sound I have lived with, but it is the wheezing sound that has prompted me to send a note in the hope of some pointers. I know the boiler is old and I am looking to have it changed but being out of work has made me think of making a temporary fix. I enclose wave file and a picture of my Potterton boiler (front panel removed). Happy to provide you with any more information you need. Thank you kindly. Red.