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Get me straight on AC system please

Dec 18, 2016
catalina 270 ft lauderdale
i have a 2004 Hunter 306. I bought it with the understanding that the AC system was not working because the pump was inop.
today i went to what i call the forward bilge directly under the table and found the pump. i removed a hose line with a threaded garden hose female fitting from the center of the pump and a steady stream of water started. sitting next to the pump was a piece of hose with an inline stop cock which was not connected to anything.I will assume there is a thru hull stop cock that picks up the seawater to be delivered to the pump. the manual does not show that thru hull anywhere. does anyone have info or better yet a schematic of how this connects please. i did order the March pump today with exact numbers. thank you
Dec 25, 2000
Hunter Passage 42 Shelter Bay, WA
Hi Tom, different brand boat here. Perhaps same boat skipper will provide input. Our two heat pumps receive sea water from a single Little Giant sea water pump. That pump has a standard marine grade hose from the through hull right next to it. All sea water hoses involved are below the water line and use standard barb fittings with double SS band style adjustable clamps at each connection.
Nov 6, 2006
Hunter 34 Mandeville Louisiana
Hey, Tom.. Most air conditioners are installed by owners or dealers and that results in components being in different locations.. There should be a thru-hull fitting and valve, a hose to a water strainer, then a hose leading to the pump. You'll have to follow the hose from the middle of the pump back to the thru-hull valve to shut off the water before changing the pump. The hose from the side of the pump is where the water goes to the air conditioner, then through another thru-hull, then overboard. It is a good idea to check the strainer monthly for clogs.. The shore power should be disconnected when you change the pump, unless you have a voltmeter and can verify that no power is on the pump wires. Picture is of a typical March pump, left side where the water enters the pump..
May 24, 2004
CC 30 South Florida
It looks like the PO had been tinkering around there and might have left some hose disconnected which may or may not belong there. Test the pump before discarding as if it is working maybe you can return the new one. Like Kloudie indicates check the strainer for clogging and even the Thru-Hull for a blockage as well as the discharge hose. A bad water pump as well as obstructed water flow will prevent the AC unit from running but it will not prevent it from starting. There is a thermal switch to protect the compressor but as the unit is cold when not in use ,it should at least start and run for a minute or two before shutting down. Either the unit has another problem or the PO may have killed power to the AC unit while working on it. Good luck.


Feb 14, 2017
Catalina 310 211 Lake Guntersville, AL
I had a water issue on my AC also that happened after I cleaned the strainer after we bought our boat. Basically the water discharge slowed to a trickle and the AC went into shut down mode to protect it like others have said. I did some research and since I knew the pump was new, I read that I needed to charge the exit discharge by putting a garden hose on it from the outside and running water back into the system. This worked like a charm as once I turned the AC back on I immediately had a stead stream of discharge water.
Jun 21, 2004
Beneteau 343 Slidell, LA
As others have mentioned, could be lots of things......blocked thru hull, clogged strainer, air in water line, and bad pump. This past spring, my pump wouldn’t run; cause was a burned out relay in the air conditioner circuitry. I could visually see discoloration on the relay and it had a burned odor. $45 for a new one and everything is good. So, before shelling out $350 + for a new pump, check to determine if you’re getting AC power to the pump.
Dec 18, 2016
catalina 270 ft lauderdale
thank you all for the help on the AC system Hunter 306. I took the deck floors up and traced the one hose from the thru hull seacock to the pump. I traced the hose from the pump to the in line to the compressor. I see the line reading out from the compressor to the thru hull on port side very forward. That line has no stop cock which i believe should. i will connect the new pump this weekend. my big question is the present pump has a two way fitting on the out side of the pump. not sure where the second hose would be going as there is only one hose going to the compressor. can someone take a pic of their pump with line in and one going out or am i wrong. thank you tom
May 24, 2004
CC 30 South Florida
I'm confused you seem to consider the discharge line as the "in" line but the "in" line in my estimation is the pickup line between the thru-hull valve, strainer and the compressor with the "out" line leading to pump and discharge port. I believe the pump may have two "in " line ports two service two A/C units with a single "out" port. If that is correct then one of the "in "ports should be blocked off with a plug. I reiterate that the A/C should start even though it may only run for a couple of minutes due to lack of cooling. Failure to start points to other issues and to the possibility that the pump may or may not be bad.