Watermaker sucking air in

[markxengineerin]

So the idea above did not work for me at first- the pump just sucked air from the vent tube. Plugging the vent tube created a perfect result, but the level of water in the filter canister slowly drops as it catches more and more air bubbles. 1x per hour or so, I would shut off the pump, open the vent, allow water to displace the accumulated air, and it's good for another hour.

I'm not sure a 1 way valve would solve this problem, actually don't think it would, as I think the pressure in the top of the canister is always going to be negative when the pump is running.

I also have not figured out a good way to do the manual fresh water flushing. On trial 1, I emptied the canister first, not wanting to have to dilute all that salt water, but then didn't have a good way to pre-load it with fresh water, due to access and what I'm working with. That part will take some more thought.

[newhaul]

Originally Posted by markxengineerin

So the idea above did not work for me at first- the pump just sucked air from the vent tube. Plugging the vent tube created a perfect result, but the level of water in the filter canister slowly drops as it catches more and more air bubbles. 1x per hour or so, I would shut off the pump, open the vent, allow water to displace the accumulated air, and it's good for another hour.

I'm not sure a 1 way valve would solve this problem, actually don't think it would, as I think the pressure in the top of the canister is always going to be negative when the pump is running.

I also have not figured out a good way to do the manual fresh water flushing. On trial 1, I emptied the canister first, not wanting to have to dilute all that salt water, but then didn't have a good way to pre-load it with fresh water, due to access and what I'm working with. That part will take some more thought.

https://www.walmart.com/ip/Stainless...xoCZdMQAvD_BwE

https://www.amazon.com/Beduan-Shaped...581016825&th=1

[markxengineerin]

How does pressure in the filter become positive, with the pump running, which would then open this valve? If it does not open with the pump running, it seems basically the same as I'm doing now- have to shut pump off to bleed air.

[newhaul]

Originally Posted by markxengineerin

How does pressure in the filter become positive, with the pump running, which would then open this valve? If it does not open with the pump running, it seems basically the same as I'm doing now- have to shut pump off to bleed air.

Would bleed the air out automatically when you stop the pump or just add a hose to the check valve to suck the air out like a small aquarium air pump. Just like bleeding the brakes on a pickup

[markxengineerin]

I'm not sure a check valve is likely to work due to the very tiny pressure changes and flows involved. Instead, I'm going to try this solenoid"
https://www.amazon.com/gp/product/B0...2AX06WG8&psc=1
Once every half hour, Arduino will shut off the pump/open this valve for 10 seconds, then close valve and re-start. I think that will take care of the bleeding without my input, at least until the valve fails. TBD how long that is, I do have some concern w/ salt involved.

[markxengineerin]

It works well, here I test the "bleed" function with the filter canister completely full of air. The automotive evap solenoid is perfect for the job.
https://youtu.be/iAIKQUNRqps

[newhaul]

Originally Posted by markxengineerin

It works well, here I test the "bleed" function with the filter canister completely full of air. The automotive evap solenoid is perfect for the job.
https://youtu.be/iAIKQUNRqps

And the Rube Goldberg award is well earned today

[markxengineerin]

Following up, system has a couple of remaining annoyances
1) I wish the inlet to the water filter canister was on the top, outlet on the bottom, instead of both of them being on the bottom. This would reject more bubbles. This is rarely an issue, and only when I'm making water in really rough conditions, like rolling in following seas. Conditions where I never would have considered making water before this modification.
2)Since I added the 50 micron filter in the "vent canister" it clogs up a lot quicker than the downstream ones ever used to. This is noticeable in certain areas that have the tiny sea slime/kelp/whatever it is. Smells like fish, easy to clean off, but a bit annoying. I think the higher frequency is a result of the pump's preference to push through a restriction rather than pull through. It can only generate so much vacuum, and eventually it's not enough. This would be less of a problem if I didn't have to do the boat yoga to replace it, but that's my fault for mounting in a bad spot. Someday I'll move it, someday I'll have a boat that has space for ergonomic systems.

[markxengineerin]

David Shih's latest video suggests that putting a grate thing over thru hull = less bubbles. Is it true?
https://youtu.be/PCPCbU_Mslg?t=526

[singlespeed]

I ended up moving my intake just in front of the start of the "keel". It works well, but I try not to run while underway in any big seas to avoid aur ingress. You may have a tough time molding the intake to the hull at that point, definitely a job to do at the next haulout. The lower you can get the intake, the cleaner the water and the less time cleaning the system long term.