Taps and sinks and non-return valves

[tforturton]

I'm slowly reviving a worn-out Westfalia kit-chen unit, and am now looking at the water supply. I don't have an onboard tank, so I'm going down the route of having two containers in the base of the unit - one for clean water, one for dirty. I've got all the bits, but I've got a little nag at the back of my mind that says there should be a non-return valve somewhere. Does this ring any bells with anyone?
I'm sure I read somewhere that submerged pumps should only be run for a maximum of five-seven seconds at a time (not sure why), and so in order to 'make it easier' for the pump, it's wise to fit a non-return valve close to the container. That way, the water in the pipe doesn't run back down once the pump stops.
If that's true, where do you find such a thing? If this is complete bunk, please feel free to tell me.

[Timwhy]

I think you are talking about a check valve. My Westy has an inboard tank and also has a city water hook up. The check valve that I added connects the inboard line with the city line, the valve stops the water from going back into the tank when the city water hook up is in use.

[AdrianC]

I think you are talking about a check valve. My Westy has an inboard tank and also has a city water hook up. The check valve that I added connects the inboard line with the city line, the valve stops the water from going back into the tank when the city water hook up is in use.

"City water" is only on US Westies, not European ones.

The only NR valve in the waterworks on ours is in the submerged pump.

[Timwhy]

The only NR valve in the waterworks on ours is in the submerged pump.

Must be different pumps too?

[tforturton]

So there is a non-return valve inside the pump itself? Okay, that answers my question then. Thanks.

[petethefeet]

Hi, we have the original Devon water tank in the back and the sink in the front. The submerged pump has an NRV just after the outlet of the pump. The NRV stops the water running back into tank when the pump stops