Water from my electric shower is too hot, why?
Check that the Stop Tap is fully open. Check that the sprayplate of the showerhead is clean. Check if an acceptable temperature is achieved by removing the showerhead from the shower hose. Check the internal lining of the shower hose is not collapsed. If the shower is delivering a flow of less than 5 litres/minute on a temperature setting of '1', then check for blockages in the inlet filter. Use a bucket and stopwatch to check flow rate.
If the problem is occurring during a period of hot weather, then you may be experiencing high incoming ambient water temperatures and /or borderline water pressure. Try setting the power selector (if available) to 'Low' and adjusting the temperature control to suit.