Figuring out how water flows between my tanks

[garyfdl]

Originally Posted by s/v Jedi

I took the “syphon” word as a common expression for water moving from one tank to the other.

In the 'engineering world' siphon is moving a fluid up above the static level of a reservoir, and then down, usually below the bottom of the reservoir, by differential pressure and no mechanical means (i.e. a pump).

[s/v Jedi]

Originally Posted by garyfdl

In the 'engineering world' siphon is moving a fluid up above the static level of a reservoir, and then down, usually below the bottom of the reservoir, by differential pressure and no mechanical means (i.e. a pump).

Yes, as I explained this happens via the two valves when levels in the tanks are not equal.

[garyfdl]

Originally Posted by s/v Jedi

Yes, as I explained this happens via the two valves when levels in the tanks are not equal.

It can happen, if the line between the two tanks is completely flooded. If not, it'll air lock.

When the boat is heeled, the water is simply flowing from one tank to the other.

As to:

Originally Posted by s/v Jedi

when one tank is overfilled, the water will run via the vent line to the other tank. Only when that one is full too, will the water run into the sink.

That depends on the resistance of the lines, and only if the air can get out of the 'other tank'. If it can't, it will 'air lock', will not completely fill, and water will still come out the vent into the sink.

[LifesBetterWhenYoureBeating]

Originally Posted by garyfdl

It can happen, if the line between the two tanks is completely flooded. If not, it'll air lock.



.

That's why In the initial post I asked if I needed to run the water pump to prime the siphon. Looks like I do, then?


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[garyfdl]

Originally Posted by LifesBetterWhenYoureBeating

That's why In the initial post I asked if I needed to run the water pump to prime the siphon. Looks like I do, then?


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You're still losing me with 'siphon'.

If the system air locks the way I said, running the pump should clear it but, based on what you've said, it doesn't clear it completely. Water still stay in the lower part of the 'U', correct?

[LifesBetterWhenYoureBeating]

Originally Posted by garyfdl

You're still losing me with 'siphon'.



If the system air locks the way I said, running the pump should clear it but, based on what you've said, it doesn't clear it completely. Water still stay in the lower part of the 'U', correct?

I'm talking about the water flowing through the supply hoses which are connected via valves to the fresh water system. That is what jedi was referring to as well. Not about the vent hoses

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[garyfdl]

Originally Posted by LifesBetterWhenYoureBeating

I'm talking about the water flowing through the supply hoses which are connected via valves to the fresh water system. That is what jedi was referring to as well. Not about the vent hoses

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OK I think I understand. The 'siphon' is the connection between the pump and tank?

So running the pump should equalize the two tanks...

IF

the vent lines to both tanks are open/clear/unrestricted.

[garyfdl]

Let me add: you should run the pump on one 'siphon' at a time. Make sure the pump is pulling water from one tank. Then open the valve to the other tank and close the valve to the first. When the water flows freely open the valve to the first back up. By pulling from one tank at a time, you should clear any air form the 'siphon' to each tank. As long as the 'siphons' are air free, the tanks should equalize... as long as the vent line(s) are also clear.

[s/v Jedi]

No, it’s still not clear. There is a siphon via the valves, not via the pump and not via the vent lines.

When both valves are open and the pump (self priming) has filled both hoses from tanks to valves, then you will have a siphon when the tank levels are not equal.

When the tank levels are equal, but you heel the boat, then they aren’t equal anymore and the siphon starts again.

If you close one of the valves, then the siphon doesn’t happen. But with both ooen, there is no airlock as long as the vent lines are functioning.

[s/v Jedi]

BTW you can fill the tank until the vent line in the sink shows a stream of water, this should not airlock your vent with water staying in that line. You must make sure that from the tank to the faucet, the hose always goes up, never a dip down. Then the water simply runs back into the tank as soon as you use some water.

[LifesBetterWhenYoureBeating]

Originally Posted by s/v Jedi

BTW you can fill the tank until the vent line in the sink shows a stream of water, this should not airlock your vent with water staying in that line. You must make sure that from the tank to the faucet, the hose always goes up, never a dip down. Then the water simply runs back into the tank as soon as you use some water.

https://www.cruisersforum.com/forums....php?p=3757498

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[s/v Jedi]

Originally Posted by LifesBetterWhenYoureBeating

https://www.cruisersforum.com/forums....php?p=3757498

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Yes, that vent line is flawed. You need to find a better route for it. For us the only way was up to the deck and the vents were installed inside a coaming on the mid deck.