Air Conditioning Water Blockage

Flytrade

Active Member
Feb 20, 2018
302
Bradenton, FL
Boat Info
2006 320 Sundancer
Engines
Twin 6.2L Mercruiser
When I turn on my a/c I always check to make sure there is a steady stream of water coming out of the boat. About a month ago there was no water coming out. I took off the hose going from the pump to the a/c and blew through it - sure enough it was clogged. I was able to clear the clog by blowing very hard into the hose. Then everything worked fine.
A couple weeks later the same thing happened, with the same results.
Last week I was at a marina and got the a/c going about 3 pm, with water flowing as normal. However, at 1 am the a/c quit, and the impeller on the water pump appeared to have failed. To get a/c for the rest of the night I bypassed the pump with a water hose, and the a/c worked fine after that.
So now the question is - what could have caused the blockage? Why did the clog reappear at 1 am with the a/c running normally for several hours? Why was I able to clear it?
My mechanic will be replacing the impeller today, and he is going to run a solution through the system to get rid of algae, etc. I'm not confident that will fix the problem since I don't see how an algae can stop the system once it's working. However, as you can imagine, I don't want to go through this again. Your thoughts would be appreciated.
 
I would flush the coil with barnical buster. Second you say the impeller failed? Did it break apart? Was it coming apart and chunks are in your coil? That would be of great concern and would require a back flush. My guess is you have some good chunkage in your coil and the hose pressure is higher that your pump and can blow it out. I would also investigate the strainer and through hull to insure there is no obstruction in supply.
Keep us posted
 
Very strange to hear the impeller in an AC pump failed. They are made out of some super tough nylon/plastic and I have never heard of one failing. Usually the motor on the unit gives it up while the little magnetic pump itself is still good. Interested to see what comes of this.

Bennett
 
Thank you everyone for your response.
Here is an update.
It seems the impeller is not directly connected to the motor shaft - it's turned my a magnet between the two parts. Somehow the impeller froze in position - will not turn.
I just came back from the boat and wanted to check the water line going into the a/c and out the boat. I blew on it and could feel some resistance, but not enough to stop the water - at least in my opinion.
My first thought was as mentioned above - barnacle buster. My mechanic said he will do that as part of the fix.
I'll let you know how that works out.
 
Thank you everyone for your response.
Here is an update.
It seems the impeller is not directly connected to the motor shaft - it's turned my a magnet between the two parts. Somehow the impeller froze in position - will not turn.
I just came back from the boat and wanted to check the water line going into the a/c and out the boat. I blew on it and could feel some resistance, but not enough to stop the water - at least in my opinion.
My first thought was as mentioned above - barnacle buster. My mechanic said he will do that as part of the fix.
I'll let you know how that works out.


Had to replace a pump a few years back for similar issues. If it dose come down to that try and get a pump with greater water supply than OEM.
 
I checked my owner's manual, and on the back they have a phone number for Cruisair - 804-746-1313.
I talked to a tech rep and he said the problem is marine growth in the system. He said to use barnacle buster and that should solve the problem. I'll let you know.
Thanks again for your replies.
 
Once you get it cleared our and running again, try some Bromine tablets in the strainer basket. When we had the boat in Bradenton/Clearwater, the battle to keep the AC lines clear was constant. Not only algae grew in the lines but little mollusks (clams/muscles etc.) would grow in there.
 
When I turn on my a/c I always check to make sure there is a steady stream of water coming out of the boat. About a month ago there was no water coming out. I took off the hose going from the pump to the a/c and blew through it - sure enough it was clogged. I was able to clear the clog by blowing very hard into the hose. Then everything worked fine.
A couple weeks later the same thing happened, with the same results.
Last week I was at a marina and got the a/c going about 3 pm, with water flowing as normal. However, at 1 am the a/c quit, and the impeller on the water pump appeared to have failed. To get a/c for the rest of the night I bypassed the pump with a water hose, and the a/c worked fine after that.
So now the question is - what could have caused the blockage? Why did the clog reappear at 1 am with the a/c running normally for several hours? Why was I able to clear it?
My mechanic will be replacing the impeller today, and he is going to run a solution through the system to get rid of algae, etc. I'm not confident that will fix the problem since I don't see how an algae can stop the system once it's working. However, as you can imagine, I don't want to go through this again. Your thoughts would be appreciated.


put this trouble shooting guide in your files for future reference.
 

Attachments

  • cruisair-troubleshooting-guide.pdf
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Just went thru the same problem. One pump supplies three A/C units. I clean/replace strainers ever two weeks. Found several small shells upon blowing out the lines. Still had low flow thru the most distant unit. Blew this line out many times, tried BB as well. Replaced entire length of that hose. Installed a pump rated for 1860gph at 50 ft head. Now I can wash the dock off with warm water. Ice cold A.C. on all three units. Priceless
 

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