hello. My display is not showing anything at all.

When i turn the dial on to auto sometimes i can see a faint display and i need to quickly press okay and the + 4 times to turn the z1 z2 z3 z4 to high and that turns on my radiators and brightens the display. As soon as i turn them off it fades back to nothing. My radiators don’t heat up unless i turn them on on the controller.