AC raw water back flush

[pmacFL]

I have two new March raw water pumps installed that are working well.What are anyone’s thoughts on plumbing a set of crossover valves to allow one pump to back flush the other filter?

[Pascal]

To back flush what filter?

[pmacFL]

The raw water filter between the thru hull and the pump. They fill with silt pretty quickly.

[SEVEN]

You close the seacock, open the strainer and remove the stainless steel screen for cleaning. Once clear do everything in reverse. Don’t forget to open the sea ock and douche k for leaks. Easy job.

[pmacFL]

That is what we do now. Way too often. I was hoping to back wash to reduce the frequency of removing the filter.

[SEVEN]

A friend of mine drilled and tapped a hose bib on the top cap of the strainer with a shut off valve. He hooks a garden hose on it to blow it backwards. He still has to clean out the seaweed that’s suck in the strainer.

[whoover]

I don't think an A/C pump would create enough presure to clear a strainer. The hose idea is the most practical.

Walt Hoover

[Pascal]

The raw water filter between the thru hull and the pump. They fill with silt pretty quickly.

So You re talking about the strainer…. First of all it should not be filling up with silt as the basket will normally let down silt thru. You can’t back flush it especially with a low pressure air con pump since the stuff in the basket will not be able to be lifted out of the basket and back thru the hose. And even if, it will get caught inside the scoop / thru hull

If you are in a situation where a lot of stuff ends up in the strainer, like in very shallow water, your best bet is to install a South Bay external Strainer. They replace the normal slotted scoop and the bronze mesh prevent grass etc from coming in. I ve used them on a number of boats.

[rwaldrop13]

I had issues with silt in the strainers/intakes, and to resolve that I had inline valves between the strainers and the pumps I could close to use this to backflush from the strainers thru the intakes, or close the seacocks and flush from the strainers to the discharge - Amazon.com: Trac Ecological 1285-B FLUSHcap - 2.5" (Medium) : Sports & Outdoors. I matched sizes with my strainers, and used dock water to flush. With the inline valve between the strainers and the pumps I could backflush the intakes, and closing the seacocks meant i could flush from the strainers thru the units and out the discharge. Worked great. During the summers (Ft Myers FL) I would have to do this and clean the strainers about 2x a week, in the cooler months 2x a month. Combine that with regular hull cleaning and it worked well.

Additional info - Perko strainer cap with hose adapter just popped up on Amazon tonight...
Amazon.com : Perko Sea Strainer Flush Cap (Small (1/2" and 3/4" Strainers)) : Sports & Outdoors

[pmacFL]

Rob W, that sounds like my situation with the warm water filling the filters very quickly.I think I plumb it like you mentioned. We have strong dock pressure.Thanks