How can I get my hot water on?

Our hot water taps have stopped working, no water comes out of them. We have a smiths etu7000 box on the wall with two buttons saying 'change' and 'program' but no matter how many times I think I've set it, no hot water (or any water) comes out of the tap. We have no instructions for its use.
The hot shower works but I think the water for this is heated independently.
Any thoughts on how I can get it working. Is there a way I can get it to provide hot water instantly rather than setting a timer? Thanks