I have a 10kw Triton Electric Shower which I cannot run 'warm'. With the setting on one red indicator and dial on first 'red' number 7 it is very hot. If I turn the dial right down to number 3 on the 'blue' (cold) numbers it does not cool down. Likewise if I select the blue cold water setting and put the selection dial to any red number to get warm water it just runs cold. Is this correct? Any info appreciated. Had it two years now so not an option to return. Good Shower but too hot.