if has an accumulator it may need inflating they look like this https://duckduckgo.com/?q=caravan+water+...2F800-03000.jpg
the sticker should say what needs pumping up to.

John, this is an old thread but I wonder if you could explain how the external water filling works on your 2023 540? I have a 2024 540 on order with on-board tank and external pump (not city water) but the information available is sketchy. If this is the same as yours could you please advise where the external pump power switch is located, inside or outside? I’m just wondering how you stop the pump to prevent overfilling? My intention is to use an aquaroll to fill the on-board tank as and when necessary.

Hi Sparks
I agree with the sketchy info re the water pump. We’re very new to caravanning and are feeling our way. We have a 2023 530 and only really felt confident dealing with the onboard water system with the help of a kind Dutch couple on our first outing. I’ve searched the internet but the only video I’ve seen on the subject failed to explain the process from start to finish. I bought an Aquaroll but just have the standard filling point and no power point to service a pump. Not sure if I should seek a retro fit or just plod on.
Sean