Marine AC

[Dan]

My AC pump and strainer are mounted in a near impossible location to access/reach in the boat, I am contemplating moving the strainer to an area that is essentially at the same height as the AC unit itself,the pump will remain at the same level below the waterline.

Weed can and does often fill the strainer in a matter of hours,and getting to it requires a midget on board and ends up being a messy affair, I have a great location I can move it to but its going to be a difficult job shifting it,before I go down that road does anyone have any input on my plan?

Thanks

Dan

Topic

[Dan]

Rodger,
Thanks for the input,I have a freshwater flush tee on the intake side of the pump now I have used it to prime the pump on occasion,the preferred time for the strainer to block and the AC to shutdown seems to be around 2AM and the bride goes on the warpath…

To clean the strainer I have to raise the entire helm section and crawl across one of the motors reach down and do it entirely by feel.The other option is to open the small access hatch and hang upside and reach down,I can just get to the strainer-either option sucks.

The genset will run for about 10 -15 hours before clogging and I can get to that before it happens, it has no external strainer and is located aft,the AC has an external slotted strainer and an internal strainer and is located forward of midship.

Both the AC and the Gen have the same size internal strainer.

This stringy weed is about 8 inches thick on top of the water,it hits the bow when the boat is at anchor and slides down the hull right into the path of the AC pickup but the majority of it misses the gen intake that is more central to the center of the boat and is deeper in the water.

As the boat is all apart at the moment its my opportunity to get creative,I’m seriously contemplating swapping the AC to the live tank pickup (it is located in the same position opposite the gen pickup on the other side of the hull ).

However that is easier said than done in this boat.

[Roger Franklin Williams]

AC Pump

Dan I have installed 50+ New AC units over the years and to make sure we could keep the AC pump flooded after filter cleaning on some units we installed a T value on pressure side of AC pump to back flush pump with boat wash down or dock side water system for priming as needed.

1 user thanked author for this post.

Jason Leslie

[Dan]

Keep us posted and pics would be great too.

Will do, it will be a while till I get to it

[Rob Schepis]

You location would be 100% good for an engine raw water impeller pump but centrifugal pumps such as these need to be flooded at all times and have no suction. In other words, they can be a pain in the ass! I agree with your plan as to put it in place by temporary means and put it through the motions. Keep us posted and pics would be great too.

[Dan]

Rob,
Yes its a March pump, the pump is currently located and will stay below the waterline, if I shift the strainer the pump would stay in a primed state from the water in the hose above it leading to the strainer above it, but would ingest some air from cleaning the strainer after startup, and thats where I may run into trouble.

I have a location in the boat that is somewhat accessible that would put the strainer half above the waterline and half below, think I will zip tie it in that location and see if it works reliably.

[Rob Schepis]

Sounds like you have a March Pump? The pump needs a flooded suction. Is the proposed strainer location below the waterline?

[Dan]

Tony Athens wrote:

Many boats do not really have the room inside the boat to install properly sized strainers and then deal with them… We use screens similar to what Rob uses, but in some cases bigger.. They are 100% with one caveat..

They need to be “looked at” a few times per year to make sure that all in intact as it should be.. And, as Rob showed, a zinc is a nice addition. We get ours from Buck Algonquin..

Tony,
I hear you and will be addressing the intake accordingly, but would still like to shift the strainer (its not a small strainer) now as I have the boat torn apart and its my only window to address the issue.

I’m unsure if the magnetic pump can handle pulling the water the water “uphill” to the strainer and back down to the pump then ”uphill” to the AC unit.Whilst the pump would remain primed its going to get some air introduced from clearing the strainer above it- hope that makes sense.

[Tony Athens]

"SQUID" Screens

Many boats do not really have the room inside the boat to install properly sized strainers and then deal with them… We use screens similar to what Rob uses, but in some cases bigger.. They are 100% with one caveat..

They need to be “looked at” a few times per year to make sure that all in intact as it should be.. And, as Rob showed, a zinc is a nice addition. We get ours from Buck Algonquin..

[Dan]

Thanks Rob,I have those for the engines,I think they would be better than the slotted style I have on the AC now but the problem would persist.

The weed is thin stringy stuff, it gets through just about any external strainer (It has one on it now) it appears out of no where here on a tide change floating just below the surface, interestingly the generator pickup sits in the aft of the boat and only gets about 1/3 of the weed in the strainer, but that strainer is dead easy to access.

Ive had it block the pickup before and use the freshwater flush connection to back flush it as a temporary fix.

[Rob Schepis]

How about installing one of these at the pickup. I don’t have an internal strainer, just this screen, never an issue and nothing to clean.. I replaced the original with one with removable screen for cleaning. Drilled and tapped it for the zinc.

[Author]

Replies