no water in hot water taps

[jaycourt]

my hot water tank in the loft is full the hot water valve is turned on but there is no water coming out of the hot water taps there does not appear to be an air lock what can the problem be

[Disco Fever]

It could be that one of the valves turns like it is open but the mechinism inside hasn't moved...

[gucciman]

sounds like an airlock to me, i get the same problem regulary with my system because the flow at the hot tap is so powerful that the hot water cylinder empties quicker than the header tank can re-fill it.
to solve it i attach an hosepipe from the cold tap to the hot tap and then open both taps thus blasting cold water up the hot pipework and clearing the blockage.
if you have a mixer tap you can do this by holding a flannel very tightly over the end of the tap and then turn both taps on, careful you dont spray water everywhere though