Turn off the water main to the cylinder or to the house and then turn off the power. Release pressure out of the taps, by opening up all taps. This minimizes any damage that can be caused whilst you are waiting for the plumber.
No, this is not true. See energy.co.za for more info.
Turn off the power to the geyser, open the hot water tap to release the pressure and allow the tap to run for 3-4 minutes. Close the hot water tap and the valve should stop dripping completely. (This applies to non-solar geysers.) If the dripping persists, you will require a plumber. Once test is complete, turn your power back on.
99% of the time, the hot and cold water system is not balanced pressure. Hot and cold water must be the same pressure.
This could be due to a burst underground pipe. Switch off all taps. Check water meter to establish whether the wheel is turning. If so, you are registering a loss. Leak Detection services will avoid the unnecessary demolition, whilst trying to locate the problem.
Yes you can, by getting a licensed plumbing company to locate the burst pipe and write you a report for submission. (This does not apply to irrigation only the main supply.)
Immediately turn off the power to the cylinder and run out hot water until the temperature cools down. Cause of fault: Thermostat or safety valve on cylinder malfunction.