No Water!

Could be 2 or 3 things.

Is the light on at the pull cord ?

No light could mean a faulty pull cord.

If the light is OK then next you need to check the solenoid, see below.

It may be your solenoid valve, you can check it if you have a multi meter, you should have a reading of at least k3.5 ohms, across the two terminals any less and you need a new valve. (Check the valve in the failed state.) (When it is not working!)

If there is power getting to the solenoid and it is not operating then there is a good chance that you have a faulty solenoid.

If you don’t have a multimeter we sell them with a guide on how to use them for checking and testing the various parts of your shower.

Apart from helping to fix your shower, they are really useful for checking you have a power supply to appliances, for checking fuses and letting you know much power you have left in batteries

(So you will know if they are good or not) and lots of other jobs, in short they are well worth a few pounds

http://www.showerdoc.com/installation/electrical-products/SKYTRO-600-005-Digital-Multi-Tester

If the solenoid is OK then Check the TCO, see below.

I think you may have a faulty Thermal Cut Out

A faulty TCO will have no continuity across the two terminals (The black thing on top of the heating tank)

Therefore a good TCO will have power at both connections and a faulty TCO will have power at only one.

(The function of the TCO is, if the water over heats it cuts the power off to the elements)

If all these are OK then you probably need a new power PCB.