Are you sure your hose to the water container is tightly on to the inlet and not on to a waste outlet point. Check underneath the caravan and trace back the pipes to the pump - or entering the floor near the pump.
Make sure all the pipes are tightly connected.
There will be air locks in the system. You need to open all the taps at the same time, hot and cold at all places - sinks, shower and give it time to purge air and splutter water. You will need a bucket, not a bowl because it needs to fill the water heater first - a few gallons.
Its pooring down at the moment but will take pictures when I can.
The inlet and outlets are all the same size and shape about an inch square with a plastic tube type thing that a garden hose can be pushed onto.when the pump is turned on it operates loud.
I didn't leave the pump on too long as I was afraid it would damage it with no water going through.
Run water down the various sinks and shower tray to ascertain drain from inlet.
Connect hose to inlet. Ensure at least several gallons in container. Open all taps - hot and cold. Switch on pump. Watch for water flowing / level in bucket dropping. If nothing from taps after a minute stop and report back. There should be sounds from taps - air coming out, gurgling, spluttering but something and eventually water.
Best if two people there or you will be running between the controls, taps and buckets. Good luck
Your inlet hose should fit over the inlet socket - a tight fit or it will draw air rather than suck water. Shoving a hose up the inlet is no good. You need correct diameter of hose pipe to neatly fit ON to the inlet socket, not inside it. Clear?
Thanks I followed all thay and realised that the black dome on the floor is a primer of sorts.the water comes out with the pump bit and then works on the pump for a short time in the kitchen but not in the bath room.
Any ideas please
Don't let the reservoir run out. Use a 40 litre Aquaroll or similar. Open all taps - shower, kitchen, bathroom and prime. Then let the pump run and you should eventually get water from all taps. Have you checked that the drain taps for winter drain down are closed and no water is escaping under the van while pumping.
If water not flowing, try closing cold taps and see if water runs from the hot taps. Reverse the hot cold procedure. See if that does it.