Pls help no hot water

[Kumark]

We just moved into our new house. There is no hot water since this afternoon. We seem to have an economy7 redring immersion heater. The top immersion element doesn't kick in to boost. I turned the switch towards + sign. Do you think the element is gone or is it the thermostat?
Thanks in advance.

 

[Tibbot]

Supply, switch, immersion and stat all have to be tested/eliminated to find the fault.

 

[Gas2Air]

Take cap off and check if it has an overheat popped out.

 

[Kumark]

There is no overheat button. Only one switch that says heater Rdt with + and - on it. I'm assuming that's thermostat. I turned it to + sign. But no luck. The supply is on. I assume I need a voltage meter to check element etc.