Mine is a "vaillant ecotec plus 937". I have turned the water dial down as you said (I believe this turns off the warm start) and the C symbol disappeared.
I only have the temperature displayed on the front now. Still no hot water.
I pressed the flame with a cross to reset and it made some noises but no luck.
I only have the temperature displayed on the front now. Still no hot water.
I pressed the flame with a cross to reset and it made some noises but no luck.