Pump working poor flow from tap.

Similarly, make sure any in line filter at the filler is gunge free.

My first thought was also the aerators, but as another thought, if you have the Whalemaster IC unit have you calibrated this? (Yellow device attached to the water inlet point, on the inside of the van). You should have a green LED flashing every 5 seconds. 

We had a problem with the pump turning on and off in our previous van when we were using the shower (fluctuating temperature) and in the end I calibrated the IC unit and all was well after that. Turned out the supplying dealer never did this!

If you change your pump you also need to recalibrate!

Obviously if you don't have the Whalemaster IC unit then the above is absolutely no help whatsoever!

Mark

Whilst I have almost always  unplugged the pump hose from the caravan before putting the pump in the aquaroll I have often wondered why. Whenever I pull the hose from the caravan there is always some water runs out of the caravan inlet fitting. If water comes out, air must get in. Whether I take the hose off or not, the pump, (a Whale) always works OK with good pressure unlike the original Truma pump.

I think the problem is caused when there is air in the base of the pump rather than in the pipework. The simple impeller will not pump air. It just whirls round and makes a noise.

Once the impeller is properly immersed in water it will have no trouble pushing air out of the pipework.