Small brown spots can build up inside the Kettle. This is not rust, small deposits of limescale that contain iron can build up inside the Kettle. To calculate the average price, we add up the cheapest daily prices of the last 90 days and divide by 90. Boil dry feature may have been activated. If the kettle is accidentally switched on with no water inside, the boil-dry device will switch off the heating element to prevent damage to the kettle. Wait 10 seconds for the kettle to reset. NOTE: if discolouration of the heating plates has occurred, this can be easily removed by descaling your kettle. Water may have gone down the steam tube whilst filling. You may have overfilled, tilted the kettle when filling or filled through the spout.