Electric screen washer always needs priming

[petesavan]

I have fitted one of those red JK electric screen washers to my 1968 T2 van and it works fine unless I leave it for a few weeks and then it will only work if I prime it first. I have sited the pump right down at the bottom beside the water tank and bolted it to the metal behind where the kick boards would be fitted, if I had any kick boards. I have also fitted a non-return valve in the pipe about half way up from the floor to the screen. To prime it all I have to do is to disconnect the pipe from just before the non-return valve and switch the pump on and then it squirts out the water with no problem. If I reconnect the pipe to the non-return valve quickly enough it will carry on working and wash the screen. But if I don't use it for a few weeks I'll have to prime it again. If anyone has any ideas as to what might be wrong and how I could fix it I'd be very grateful.

 

[tbird]

The non return valve should hold the fluid and stop it returning to the tank. So it suggests that either the non return valve is not working or their is an air leak on the tank side of the non return valve.
Trust that helps

 

[Moseley]

The fluid level in the tank needs to be above the motor so that fluid remains in the inlet line, and any air that bleeds into the system finds its way back to the tank. Also, it may help to locate the non-return valve closer to the pump outlet as this will help keep fluid in the line and not drain back from the pipe up to the valve.


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