Hi, I changed the taps on the bath and the valve tap in the airing cupboard, all the tanks were drained. Now I have no hot water coming out of any of the taps. I have tried the suggested washing machine trick but that has not worked. The hot water tank in the loft is not filling up. Any more ideas?

Hello, did you turn the valve off at the water heater? If you did then it's the gate that has broken inside the valve and is not opening.

Truck has made the smartest advbice where to start checking. You closed that valve and it may have failed to reopen.