NO HOT WATER!!!!! [ICOS IDEAL boiler] ?

Hello

i have an Ideal Icos boiler and a while ago the button on the programmer for hot water stopped working, it was a Danfoss one.

then i bought a new one (not the same one) but when i press hot water the boiler turns on (at least makes a noise) then no hot water, and it says c on the front of the boiler, and i think it supposed to say h for hot water and c for central heating?

anyway i have no idea what to do now so any help would be greatly appreciated :)