Electric power shower/no water?

[Nefertari]

I have a Redring Expressions 520M shower. It runs off stored hot water.

there is power to the unit but no water comes out. this has happened before, i leave it a day or so then it works fine for a while then stops again. Don't think it is an airlock as I lower the shower head to see if it makes any difference (It doesn't)

any ideas please?

 

[seco services]

More likely the solenoid coil faulty, you need a multi meter to do some checks on the coil.