Duetto Water Pump

Going through my new (to me) Duetto, which has been unused for several years, I cannot get any water to pump up to the taps. I can hear the pump running, and have tried priming by disconnecting pipe from tank and attaching a hose with a slow flow from my outside house tap. When this is connected, I can purge the system, and water flows where it should. However, on reconnecting pipes, pump is running but not pumping. I assume pump is duff, probably dried out over several years of inaction. So, question is, where is the pump situated on a Duetto???  Cant see it anywhere, but it sounds like it must be at the back of the sink by the tap, but how to remove sink without damaging it?  Have removed screws, but it seems to be fixed down, probably with silicon etc, and trying to lever it up is going to damage it. Any ideas?

Usually on the van conversions of this age, the pump is under a false floor or behind a false back panel , of a cupboard under the sink/cooker area.

Thanks, I have now located it, as you say behind a false cupboard back below the cooker, I had to cut the panel in half to gain access. Still very difficult to access pump, although at least I can now see it!!!

On the 2003 Duetto we owned, access to the water pump was from the outside once the lower fridge vent was removed.

Shortly after we bought out Duetto in 2007 the pump failed which I then replaced. I also subsequently added a Whale surge damper next to the pump which made a big improvement. A simple job with the addition of a T-piece and a short length of appropriate sized diameter plastic pipe, and a gaffer tape sling to keep the surge damper vertical. Without a surge damper in the system the water pump would kick in about every 10 minutes to maintain the water pressure.

As a water pump ages the valves can become incompetent causing water from the pressurised side to leak back to the low pressure side past the valves, the pressure falls and the pump is briefly reactivated. This can happen repeatedly over a few mintutes, this is not helpful if you're wanting to get to sleep, it also wears out the pump sooner than would otherwise.

can be an air leak issue reducing the pressure on the tank side, I had this and eventually found a small leak in the hot water tank. Worth a good search for leaks - hot water tank should be under sofa on the driver side