Clogged raw water lines or thru hulls?

[Jon4399]

I've been away from my boat for a month or so, and went down the other day to clean the AC strainer. The strainer was not too bad, but when I put it all back together I found the flow was only about half it's normal flow. And the AC unit did not seem to be putting out much cold air. I contacted a local diver to clean the hull and check the raw water inlet. He suggested the line may be clogged. Has anyone else had this problem, and how do I fix it? The diver suggested a local AC guy who would chemically clean the lines.

[djmarchand]

The line itself doesn't build up scale (but may have a mussel growing in it). But the condenser coil does and can be cleaned with Rydlime, Barnacle Buster, CLR, etc.

David

[forsailbyowner]

In the adler barbour manual it describes how to flush the system with muriatic acid.

[Jon4399]

Can I simply pour in CLR into the screen filter housing. Then button things up and turn it on?

[Jon4399]

Forget my last post, as I have done some more research. It doesn't seem as easy as simply dumping in some CLR in the strainer housing. Guess I'll install some new fittings in the hose near the thru-hull and work from there.

[MarkJ]

I had this problem a few weeks ago with my salt water electric pump into the galley sink. All of a sudden it was just a trickle.

Popped out the gauze filter and cleaned it but that didnt make a difference. Then with the pump on and looking into the filter through the clear plastic dome with a torch I saw something silver on the sea side of the filter. I pulled it apart and pumped a bit of water and out popped a little FISH!!!!!!!!!!!!!!!!!!!

He was tiny! And still alive so I put hiim back in the water.

I call them Rudder Fish because they live between the top of the rudder and the hull. They seem to be in most tropical waters world wide. I went to cleant the bottom of the boat later and there he was

[jstevens]

Before you go to the trouble putting chemicals through the AC plumbing, I would check out the hoses. If you are in an area that has a lot of jelly fish, one could have been sucked into the intake and stopped before getting to the raw water strainer. If you open the raw water strainer do you get good water flow? If not then something is clogging the hose from the thru-hull to the strainer.
Next I would disconnect the hose from the strainer to the AC at the strainer and connect it to a hose from the dock water supply. Turn on the pressure to the AC slowly and see if a lot of crud comes out the discharge thru-hull. If you still get poor flow with nearly full water pressure or get a lot of back pressure from the AC, then it is time to go to the chemicals.
Here is a link to my having a similar problem with my water cooled frig compressor: Simple Repairs

John

Edited to correct the first sentence in the paragraph above to read, "Next I would disconnect the hose from the pump to the AC at the pump and ...."

[Cheechako]

Are you sure the inside of that thru hull isnt clogged with barnacles?

[muskoka]

We've had everything from catfish being sucked up the intake to barnacle encrustations which reduce the flow to a trickle.

The first step is to make sure water is flowing freely to the sea water strainer - open the strainer with seacock closed then open the seacock to make sure the water flows that far. If that's OK then the problem is downstream from that. Sometimes the barnacles clog the exit pipes if they're below the waterline so inspect those. Also, make sure your seawater pump is working and properly primed!!

If the pump, inlet and outlet appear OK then you need some Barnacle Buster to be circulated in a loop through the system to clean it.