Mira electric shower. Thermostat?

[hard-work]

A Mira sports max airboost electric shower approx 3 years old.
When switched on, it's turns cold for quite a few minutes whereas it usually runs warm-to the temp it's set at. After few minutes of running cold, it then runs scalding hot. When adjusting the temp on the dial to make it not so hot, even adjusting the dial a tiny bit, it runs cold... then when adjusting to be warmer it runs very hot. It sounds like the thermostat is kaput to me. Does anyone familiar with Mira showers know what the problem can be please? Thanks.

 

[hard-work]

Tried the usual kinked hose and blocked shower head.

 

[terryplumb]

hi. must admit I am not familiar with this particular model and you have not said what kW size is. anyway a few basic questions for you. forget the dial for a minute cos really all that does is control the flow, think you may have 2 buttons at top to select heat settings,do you get same problem on either setting ? and if you remove shower head ,so just hose connected, let run for several minutes ,monitoring temp of water with your hand,make no adjustment and advise what temp fluctuations you find.

 

[hard-work]

Thx. It is 10.5 kW It sees to happen no matter what. There is no thermostat?

 

[terryplumb]

so as I asked, if. you let it run several mins making no adjustments what happens ?? cold then hot cold then hot ? as I said not familiar with your model but most work on following principle :- heating element/s ( as more than one ) are energised when you switch on and stay on whilst water flows.bottom dial controls flow ,slower the flow ,hotter the water gets as it moves slower picks up more heat .vice versa put on fully anticlockwise water flows thru faster so comes out slower. very unlikely that a thermostat is required .but an overheat stat would be .from what you said a small adjustment ,of the flow makes a BIG difference, hence want to know answer to my question above .

 

[hard-work]

Thx I will check it all out again. It is not my shower. I think electric showers are made by Satan.

 

[terryplumb]

ha ha, think mira and tritan were his daughters wernt they !!! anyway my money is on the PCB ( 100 quid ish ) or the overheat stat ( thermal cut out ).