Exterior cavitation in 12v water lines

[pickards5]

Hi. Have had our van for a while and I lived in it for work, it was great after the camper trailer I was in for the first year. I always used mains water then. Now we are all living in the same town we have time to go caravanning . We have now had a number of issues with the water.. The repair man was very good, but is 4hrs, away sorted a lot of the old problems when we went there. But just went away and had new problems. On spending more time under the van I saw the pipe after the filter on the way to the 12v pump was cavitating the water. Have removed the filter and everything seems great, but not sure if this ok to do. Does everyone have them. They seem to change how they build them all the time. I can't find anything else where in the threads about people having this problem. Cheers

 

[ShaneT]

Did you remove a water filter or a screen?
As the filters are a option I see no problem in removing it as long as there is still a screen on the pump.
Do you drink the tank water? If you do I would buy another filter write the date on it and change it as recommended by the manufacturer.

 

[pickards5]

Shane it is a course screen, plastic basket type, under the middle of the van and not near the pump. We filter the water into the tanks and drink it. cheers

 

[Hubble80]

@pickards5 I'm gonna ask a stupid question here, as I am not fully understanding your issue...

Are you running the pump when you have mains water connected? If so this will cause cavitation of the pump.

 

[pickards5]

No not running the pump with the mains connected. What seemed to be happening is that the 12v pump wanted more water than could be passed through the filter causing lots of air to form in the line then terrible pressure at the tap and shower and lots of bubbles and air at the tap. Hope that is clearer.

 

[brookes2622]

I am having a similar water cavitation issue, especially in the bathroom where it cough and spits something awful. After a few minutes it flows ok but the pump will continue to run if you haven't run the tap for very long.

I'm assuming air is finding it's way into the system. Is there a method to determine where this is occurring, a process?

 

[brookes2622]

Righto I suspect I have found the problem. The hand pump has never really worked and I haven't really cared as I have never used it. But it looks like it was letting air in past what looks like a one way valve. Replaced the hand pump with a cheap and cheerful and the cavitation seems to have stopped.

Is there a reco kit for the original pump given it seems of good quality?

 

[boots33]

Hey brookes
We had the same problem with our hand pump. Ours had a non return valve mounted just below the hand pump which would not seal off properly. I tried a couple of caravan type non returns but they didn't work either. In the end i got one like this and all has been good since .

 

[brookes2622]

Hey brookes
We had the same problem with our hand pump. Ours had a non return valve mounted just below the hand pump which would not seal off properly. I tried a couple of caravan type non returns but they didn't work either. In the end i got one like this and all has been good since .

Yeah thats what I was thinking but once I had water above it, it seemed to hold. I am getting a small amount of air in through this three way so I am going to get some clamps today.

 

[Drover]

Just had the same sort of thing happening, the 3 way tap from the tanks was leaking air so replaced it with 2 garden irrigation taps, hand pump disconnected now as I needed the T piece. The big silver flash looking hand pumps don't have spare parts available so if the O rings fail you have to shop around for them.
No air in the lines now.

 

[brookes2622]

So hunting around proved fruitless. As stated about there are no spares for the flash silver handpump. To make matters a little worse I did replace the flash pump with a $20 cheapie (old school pump) fix the problem mostly and putting clamps on both the "T" peice and the "elbow" before it solved the air seeping in. But, and isn't there always, the cheap pump stopped the ability to move the main tap stem out of the way when doing the dishes. Well, I now have a new flash pump. I've been told to lube the rubber washer with silicon to help preserve it and make it last so will do.

Must say it is nice not having the bathroom tap spit at you when brushing your teeth.

 

[Drover]

I ended up putting hose clamps on the joins to make sure they sealed as I did find an air leak on a barbed joint. Did you check the hose places for O rings ad well as hardware places ? Just that I haven't got around to lookinf for new O rings yet. Always found vaseline good for pump parts .

 

[macca]

My theory was that seeing I have a pump and a tank, I didn't need a hand pump so I pulled it out and put in a filtered water tap, connected to mains side which works with pressure pump.

 

[brookes2622]

My theory was that seeing I have a pump and a tank, I didn't need a hand pump so I pulled it out and put in a filtered water tap, connected to mains side which works with pressure pump.

Yeah that's what I was thinking to do, but I couldn't shake the thought of having no power and no water. Irrational I know given we are never really far from water and with reliable solar etc, but if the pump fails no water.

The other flaw was that would leave a hole in the bench as I already have a filter water tap.