help!!! The JG pushfit isolating valve on the 15mm hot water pipe going to my bathroom wash basin has failed and is leaking. I have managed to turn it off but the problem is the main hot water stop cock is jammed. Can anyone say other than me getting wet will I encounter any problems if I take the isolating valve off and push on a new one, I assume there will not be the same pressure of water that is in the cold mains. The hot water is fed from the immersion heater.