This is definitely one of the more “nice-to-have” modifications of our van. However, the solution came out really neath with yet an another button to the dashboard!
The existing disposal system required opening up a valve underneath the car. While manageable then not the most neath solution. On more modern campervans the solution is an automated valve. So I thought, why not have the same solution on our 25 year old campervan!
First, I bought a cheap solenoid valve. While it did work, I found that this type of valve requires a certain minimum differential pressure across it in order to fully open. Such pressure (around 1 barg equivalent to 1m fluid column) would not even be the case with a full grey water tank. As a result the outflow is extreme slow and it would take hours to dispose 70 liters of grey water.
Instead I found that an automated ball valve would serve the purpose better. Searching for an automated ball valve, you can find different types depending on functionality and wiring options. I bought one which only needs a + / – current as it has a small capacitor which is being charged in open position and supply current for the motor closing the valve after disconnecting power.
As you can see below, the disposal is quite efficient.
The hack is really easy. It just requires the right valve, a switch and a bit of wiring. For water protection driving on wet roads, I wrapped some rubber shield around the valve as seen below.
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