Hi, Check your hotpress and look at cylinder. You will see two pipes sticking out of it about 18" apart and parallel, you should see a valve with a red round handle, turn it anti clockwise(lefty loosely, righty tighty!) to ensure it's open. this valve is used to balance water flow and should be half closed when everything is working right. If thats open, check for a valve that has a box on it and a cable running from it (its a motorised valve) you may have two, 1 for heating and 1 for hot water. When these things go wrong their default position is off.
Once you have found it there is a little lever on the side, you may have to run your fungers around it to find it. when you locate lever pull to the side and when you can't push it anymore press up and it should fit into a little grove and remain open. I.E you have manually overidden motorised valve. The valve may need to be replaced but this should give you hot water for the time being.