In our NV200 we fitted an electric dump valve so that we can empty the grey waste from inside the van – no more getting wet when its raining or having to bend down to turn the tap on or off. Simply flick a switch and bye bye water.
“Proper” kits for this are quite expensive but its actually a simple project if you know such things exist. You simply need a ball-valve with 12v solenoid connection adapters wires and switching. Simple!! Amazon sell all the bits you need below.
You need a ball-valve as this will seal well, is designed for infrequent use, and won’t jam when there is crud going through it.
The style you want (to make life easy) is CR04 – which is a 2-wire connection. This is normally closed. Apply power and the valve opens. Once power is removed the valve closes (under its own power). So no need for relays or DPDT switches – simple power to open, remove power to close.
The valve is, weirdly, much cheaper on Amazon than ebay, but the connections are (currently) the same price on both. We’ve gone for 1″ valve (20mm internal diameter) and 25/21mm connections. The straight piece will be to connect to 1″ pipe from the tank, and the elbow to simply divert water “downwards”. We will make a bracket and mount the solenoid on a bracket in the right place.
Simple 12v on/off switch is all you need to send +12v and earth to the solenoid.
This is an easy add on – you can either modify your existing water outlet, or indeed at a second waste tank outlet so this could work in parallel.
Hope this is useful