The mains cold water supply temperature increases during the spring and summer periods. This means that the temperature knob will need to be adjusted to a higher flow setting (colder setting). The switching to full cold that you mention is caused by the thermal switch on the heater tank operating. The thermal switch will cycle the heater tank elements on ond off until you increase the flow rate through the tank by turing the temperature knob to a cooler setting at which point the cycling will then stop and you will receive a constant showering temperature.
garryk
April 2010
I have a 9kw sports shower which is usually on the 'High' setting. Recently the 'HOT/COLD' control has become very sensitive to adjust the water temperature, as one moment the water is very hot and by a miniscule adjustment towards a cooler setting, the water suddenly goes cold and the flow light extinguishes. I've checked the inlet filter. One would have thought the Flow light would have stayed on if the adjustment allowed more water into the system!
John Temme
April 2010
Sounds like you require a new flow valve. You can purchase these direct from Mira or they can come out and repair your shower for a fixed price of £129. You can speak to them on 0844571 5000
XTC7MUSIC
April 2010
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