unvented cylinder hot water

Hi all, I have just moved into a rented property and it have a unvented heater tank for the hot water. I am getting no hot water at all and just wondering if the knotches on this timer dial need to be in or out for it to be on? I suspect the timer is broken as when I set the current time it...

Hi, Pretty sure I know the answer, but I presume this means the cylinder is done with and needs replacing? There is a small amount of water coming out when the hot water is on (it's system water not the hot water). The dent was there when we moved in and appears to have been done before or...