This is a weird one, I don't have much experience with Mira showers, my first one ran faultlessly using a gas combi boiler, however, my later purchase, a self contained Mira, that has it's own internal heaters is giving me some headaches.

 

The shower, when connected normally to the water main used to work fine, recently it has decided for some reason to act up.

 

When you turn on the shower there is no water flow whatsoever, and the shower immediately goes into "OVERHEAT" safety mode and disconnects.

 

I have checked the water flow to the shower and there is plenty of water / pressure there so that does not seem to be the problem.

 

Now comes the weird bit, if I turn on a hot water tap in the bathroom (which activates the combi boiler) and possibly reduces the main water pressure slightly, then switch on the Mira, the damn thing works just fine!

 

Any idea as to what might be going on?

 

The Mira has its own main cold water supply, the hot water taps are fed separately from the main water supply but are going via the Combi boiler which in this setup can only be affecting the Mira supply by slightly reducing the Mira water pressure.

 

I can understand the Mira having a safety cut out when water pressure at the inlet is too low, but does anyone know what might be happening if the shower is getting too much pressure? (got me stumped)

 

Cheers!

Try blowing compressed air through it, put the air into the outlet, has worked for me, a non return valve blocked or stuck maybe