Water system -Duetto

Recently bought a Duetto and for the first 4 weeks ,all was OK but last time out , I filled tank and started to set up. When I switched on 12v system on Zig unit, water pump kicked in to pressurise system but didn't stop. Also later that day, having switched pump off, we went out to local shops in the van and when parked on slope, water was seen running from top of tank.All water was turned off and we used site facilities. Returning home, van was put on ramp and tank was removed and inspected. It appeared that the inspection cover was not screwed down properly. I would have expected leakage,but the flow was quite heavy. I have tried following pressure side of pipework but everything is fitted behind panels and things are built over or in front of each other and I can't see how to get to pipework to check integrity of pipes and fittings, without dismantling half of the interior, which I am loath to do. Can anyone help?  Frank Randall

Frank.....if since returning home you've had the tank dropped and the cover tightened back up, exactly what is the problem now? Are you saying your pump is still running continuously when pressurising and if so, how long? Have you run enough water through the sink tap to pull any air locks through?

I can't quite figure from your post what you are saying is still wrong.

Thanks for your reply Bulletguy, the tank went back in to van this evening and as yet remains unfilled. Tomorrow will fill tank and will restart pump  and bleed air from system starting with nearest outlet.Will let you know if problem persists. Frank