Boiler
Everytime my boiler heats water it makes a loud whistling sound
Answers
A whistling sound when your boiler heats water can be caused by a few things, most commonly limescale buildup or trapped air. These issues restrict water flow, causing it to heat unevenly and create steam that generates the whistling or kettling noise. Other possibilities include a faulty pump, a leak, or problems with the thermostat or pressure relief valve. It's best to consult a qualified gas engineer to diagnose and fix the problem
Sounds like ketteling the pump may not be getting rid of the water out of the heat exchanger quick enough so it bubbling and possibly the auto air vent working
