Water pump testing ?

[TomDub85]

Hi so on my new van the water pump is from what I can tell is working making all the right noises , but after adding 15ltr of water into the tank and nothing has came through the tap yet been under the van and can not see any sign of water leaving the tank and the pump is buzzing away. Do I fill the tank more ? Disconnect the pipes and check for blockages ? Or put my hand in my wallet and put in a new pump ?
Noticed the tank has 2 indents within it so parked on a down slope to make sure the water would pass over these. Seems all air tight for pressure . if someone could help that would be great explain how the pump works and if it would run until the tank was empty if working?
Thanks Tom & Lou

[TomDub85]

Its a whale inline 991 pump if this helps .

[jamesandtheopenroad]

Pump needs priming if its nor gravity fed. Is there a foot pump to start it off? If not, turn the tap on and give it a good suck until the water is pulled into the pump.

[TomDub85]

Worked a treat thank you