Seafrost Fridge gets air in the water cooling line

[Bravo46]

I addressed this exact same problem last week with advice from Sea Frost.

Water hose is probably 3/8 ID so get a 3/8 T, a length of 3/8 ID hose and a valve for the end of it, plus the required number of hose clamps. I found all the parts at Lowes.

Insert the T on the exit side of the pump, run the hose off the T to an appropriate place in the bilge, and install the valve at the end.

When the pump gets an air lock, with the pump running, open the valve and in seconds the air lock will clear, and water will come out of the valve. Close the valve and you're done in ten seconds. Works like a charm, simple and inexpensive.

[skipgundlach]

That's a brilliant idea. I wonder why Cleave didn't suggest that to me, and to everyone who installs that?

My water, in that volume, doesn't all make it to the bilge; some of it goes into the pan under the engine, making for floating diapers (oilsorb pads) until the water evaporates.

Leading some inexpensive line to the bilge, with a plastic ball valve inline and easily reached, would massively simplify my life, as I have to 1) crawl over the engine to get to 2) remove the floor plate under which the through-hull and pump are located and 3) use a wrench to loosen the clamp to remove the line which then 4) puts a small volume of water into an area where some of it inevitably goes under the engine.

A line led directly to the bilge, and a shutoff accessible from outside the engine room (I have long arms) would improve my attitude greatly!

Thanks!!!

[sailing_gal]

This sounds similar to what I was thinking about, I was just going to make a bleeding tube... question- does that hose with the valve on the end have to lead UP? Or can it just make a run directly to the bilge? Unfortunately, my pump is located under a floor without direct access to the bilge in a compartment that doesn't drain (sigh), so I would have to run quite some hose.

But I was thinking of bleeding the air before it got to the pump, the pump won't run if there is air in it, so how does that work properly?

[Typhoon]

Be careful don't sink your boat . The air bleed off hose must go as high as possible above the water line .
Regards John

[sailing_gal]

Yes, I can run mine into the lazarette and then quite high from there, it is just going to be about a 5' run before it can bend up.

[Typhoon]

That's just fine you should increase the hose size and use a large diameter tee so the water velocity does not suck in air past the tee bleed off and back into the pump again . The bubbles need time to rise out of the stream . Remember all this work will be below the water line so make sure every thing is of good quality and heavy . No cheap stuff down there. Double clamp everything.

Regards John

[sailing_gal]

Thank you, John. But I still do not understand how that system will work after the waterpump, since the pump doesn't pump if there is air in it. My plan was to put the T into the system before the pump- as in the drawing you did.

[Typhoon]

Does this look right ?

Air bleeds off before the pump .

[Typhoon]

Sorry came out sideways .

Regards John

[Bravo46]

My pump runs just fine without water and has for many hours in the last 10000 miles. I chose the T at the exit because that was the SF recommendation and because I had tried every other hose connection/location - the exit side is a clear and dramatic winner on our boat.

[skipgundlach]

Originally Posted by ColdEh Marine

Does this look right ? Attachment 152847

Air bleeds off before the pump .

The bleed has to be at the exit. You should already have a substantial head (distance under water) to push water. If you are going to rely on a standpipe to deal with entrained air (if that would work; it presumes more pressure from depth than the volume of suction from the pump), it would have to be above the waterline at all orientation of heel.

Granted I've never tried it - but I know that a very brief opening of the pump exit while it's running, if the intake is not clogged, cures it. As that's the pressure side it makes more sense to me - but you could well be right, if you can make that standpipe work in your available space.

[sailing_gal]

I will have to think on that. It would be easier to put that bleed pipe closer to the compressor after the pump because it is in the lazarrette. The through-hull and waterpump are very close together under the floor of the galley with about a 5 foot run to the lazarette. I just worry that because it is a fairly long run, with air in the system, the pump simply might not work long enough to clear the air out. When there is an airlock, after I hit the reset button and the unit has cooled, the pump will run for maybe 15 seconds before shutting down again.

Thank you all for so much helpful information.

[Scrimshaw4]

I have the same system installed and plumbed the same way. While the Jabsco is noisier than a centrifical it's the only way to get around hull bubbles / air. JMHO

[sailing_gal]

After thinking about it some more, it seems more convenient to put that T in front of the pump to remove bubbles before they get to the pump, and I would not need a valve at the end. Plus, added bonus, it can be used to clear any obstruction in the thru-hull. Last option- as said- switch out pumps....But it would sure make it noisy- especially since mine is located right under the galley floor.