Electric Shower not working

[Dragonista]

*Maiden post*
I have an electric shower Triton T70si installed 2 years ago and has been working fine until yesterday.

The pull cord switch light is ON, but when I turn the power selector (top dial) anticlockwise to either the blue or red line(s) the light on shower unit does not go on, and the light on the pull cord immediately switches itself Off. No water flow. When I turn the dial back to original position 12 o'clock the light on the pull cord goes On again.

I had the shower hose resting on the bath yesterday and I put it back on its attachment - could that be the reason of the shower not working. I read in the booklet something about 'back flow' etc but couldn't understand it.

Any help is appreciated and if I have to get an electrician in at least I have an idea what to ask him.. Thank you.

 

[jj4091]

More likely to be a burnt or loose wire or terminal in the pull cord isolator switch.

 

[flameport]

I had the shower hose resting on the bath yesterday and I put it back on its attachment - could that be the reason of the shower not working. I read in the booklet something about 'back flow' etc but couldn't understand it.

That is where dirty water in the bath is sucked back into the shower due to a pressure drop elsewhere in the system.
Shower rails have a retaining ring which the hose should pass through to prevent the shower head being placed in the bath. It also prevents the head from being dropped and breaking a hole in the bath.

None of that is anything to do with the shower not working. It's the switch, and inevitably it will be the neutral terminal that is ruined.

 

[PrenticeBoyofDerry]

Isolate the shower circuit, prove dead by using approved voltage indicator.
Then check at isolator and shower for loose or damaged connection.
If you have a voltage indicator confirm voltage at both isolator and shower unit.
If you have power and still no water flow, then you will need to check across the solenoid for continuity, using a continuity tester.
A reading of no less than 3.5kΩ would be expected, if not the solenoid is goosed!
If you do have a good reading then it could be that you have low pressure or blocked inlet.

Backflow would not cause this problem.

 

[bernardgreen]

The fact that the neon in the pull cord switch goes OFF when the shower control is turned ON strongly indicates the supply to the switch is high impedance. Enough power to light a neon can get to the switch but not enough to power the shower.

As has been said this is almost always a failed connection between consumer unit and the switch, most commonly one or both of the screw terminals in the switch Input side will have falied.