How to isolate the Quooker from the Water Supply? Troubleshooting

If you need to shut off the water supply to your Quooker, press the Q shaped button on top of the tank to switch the tank off, then run the boiling water tap until it runs cold. 

Next, locate the Quooker's inlet combination/shut off valve (a brass valve between the tank and cold water supply as indicated in the below image) and turn the small grey knob to shut the water supply off. 

Please make sure the Quooker tap is not used and the tank is not switched back on while the water supply has been shut off.