Hi, My boiler is acting strange. (Buderus N5C) It has started making noise when nobody is using any hot water and the central heating is not on. Switching the hot water on stops the noise, then as soon as you turn the tap off then the noise returns. I've attached a recording of the noise in the hope somebody can suggest what is wrong. Here is the file: http://www.filedropper.com/boilernoise and here: https://clyp.it/k13f4hjt?token=c61acd98071cea5a253f0eb2172b6512 Thanks, Andy.
Is there any discharge from the safety drain pipe to the outside (if it has one) ? Whats your pressure gauge reading ?