Ok i thought that purefreedom told me it needs to be in sideways .the valve doesn't open either way
Sorry I may not have been clear. You can buy float valves that fit in the top of the tank or the side.
Purefreedom should know what type they supply.
If its not opening the 'fill' valve then there is something wrong.
Is the system 12v or 240v mains?
If its 12v then its safe to 'play' with. Normally a 12v fill valve just needs 12v (0v and +12v) applying to the terminals of the valve to open it. The float switch normally just cuts the supply to the fill valve to shut off water when tank is full.
Hope that gives you a clue?