Air in waterlines

[gbsteffo]

Hi,

Got an Island Gypsy 44' with 4 fresh water tanks (400 gal total), pressurized with Groco Paragon Jr pump and 1.5 gal accumulator tank. There's two saddle tanks (forward and aft) and two tanks in engine room centered in bilge 4-6" from bottom (lowest point of water source).

I have a re-occurring issue with air getting in the lines once water level is at about half capacity. Waterline leading to pump runs along bottom of bilge and is fed by two saddle tanks and the forward mid-line tank in engine room. The tanks in engine room as connected via a 2" hose. When air start appearing in system I have opened up 2" hose and water is gushing out. Likewise, water flowing strongly out of waterline from forward engine room mid-line tank. I also shut off both saddle tanks when the whole system was fully loaded. I ran the two mid-line tanks dry, then opened up both saddle tanks thinking that should feed the water main line. This did not happen water spigots where spitting like never before. I'm totally stomped (obviously, LOL) I have no idea where this air source is coming from as it appears to be connected to the water level...

Part of me thinks that perhaps pulling individual lines to a central manifold would be a solution, but I've also heard other people having this issue have done just that, with problem still remaining.

Cheers,

Stefan

 

[Lepke]

I suspect you have a leak in the lines before the pump that is so small water doesn't leak, but the pump suction can draw in air. It could be some tanks don't have big enough vents, have some restriction that causes greater suction, or you have a hose collapsing when the pump is running on the suction side.

 

[Wxx3]

I suspect you have a leak in the lines before the pump that is so small water doesn't leak, but the pump suction can draw in air. It could be some tanks don't have big enough vents, have some restriction that causes greater suction, or you have a hose collapsing when the pump is running on the suction side.

+1
Whenever I've had this problem, it's always been a fitting or clamp that is not as tight as it should be. this allows the pump to suck some air, but water will never leak.

If the hoses are old and you have fiddled with any of them, I would cut a few inches of the end and re-clamp to the fitting. Hard, inflexible hoses have been the cause of most of my air intakes on the suction side.

Also, a bad valve on an empty tank will cause those symptoms.

 

[HopCar]

I think Lepke is on the right track. The fact that it starts when the tank is half full makes me think the pick up tube in the tank is damaged. As long as water covers the damage, no problem. When the water level drops to the damage, it sucks air.

If there is no pick up tube and the pump attaches to the bottom of the tank, you got me. No idea.

 

[gbsteffo]

Ah, thank you all for responding. You've given me renewed hope and restored sanity (at least for now, LOL). I will try and "re-hose" and report back!

Thanks again!!