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Hunter 410 Air Con Seawater flow

Jan 12, 2011
930
Hunter 410 full time cruiser
I am currently living it up in a marina with almost free electric so am running the air conditioning. Over the last couple of years I have noticed that water flow out the aft air con slowly reduces tll I flush is etc., but the flow on the forward doesn't slow down unless the strainer clogs up. Just wonder if other 410 owner have noticed the same.
 
Dec 25, 2000
4,946
Hunter Passage 42 Shelter Bay, WA
Different model boat, here, Don. Our AC system setup similar to yours.The same sea water systems serves both units; one in the main cabin, the other in the aft cabin. Never a difference in water flow between the forward and aft seawater discharge through hulls. The only suggestion I have would be to check the hose from where it connects to the system discharge port and the through hull. Perhaps a manifold freezes up after the system has been running for awhile thus restricting water flow out the aft port. A puzzle for sure.
 
Jan 12, 2011
930
Hunter 410 full time cruiser
Well I got a circulation pump and Barnacle Bruster and setup a loop and flushed systems. Got a lot of dirt etc out of the aft SW loop and could tell it had restrictions in it and slowly it cleaned out. Did the forward loop and mostly just got a little dirt of of it as it has had good flow the whole time. So I don't know why the aft clogs up and the forward doesn't and will see how it changes over time.
 
Dec 25, 2000
4,946
Hunter Passage 42 Shelter Bay, WA
Got a lot of dirt etc out of the aft SW loop and could tell it had restrictions in it and slowly it cleaned out.
It appears you found the culprit, Don. Perhaps a flush out each season will prevent the blockage from returning. No idea why the aft hose clogs and the forward one does not.
 
Jan 12, 2011
930
Hunter 410 full time cruiser
I flush it with dock hose regularly. Apparently things settle in the aft as i have fought it before. But it isn't much longer of a run.

Anyhow, now i have the pump etc to flush it when needed.
 
Jan 12, 2011
930
Hunter 410 full time cruiser
Since doing the cleaning I can not believe how much colder the air coming out of the air conditioner is. It blows so cold now you start thinking of socks and long pants while it is running. I have to run a fan in the salon to move the air around to reduce the AC cycling as the control thermostat is getting cooled off to fast :-0
 
Dec 25, 2000
4,946
Hunter Passage 42 Shelter Bay, WA
Appears you fixed part of the problem. Do you suppose there is a deep dip in the hose somewhere that allows sediment to build up over time thus restricting sea water flow? Cannot think of another reason for sediment to build up like that to the point it needs periodic flushing. The sea water flow on our system is good and steady, but not strong through both discharge ports; just enough to allow the condenser to do its job, whether cooling or heating.
 
Jan 12, 2011
930
Hunter 410 full time cruiser
Appears you fixed part of the problem. Do you suppose there is a deep dip in the hose somewhere that allows sediment to build up over time thus restricting sea water flow? Cannot think of another reason for sediment to build up like that to the point it needs periodic flushing. The sea water flow on our system is good and steady, but not strong through both discharge ports; just enough to allow the condenser to do its job, whether cooling or heating.
It seems that way, but I don't see where it could be. I have found/decided that the smaller aft system passes less water no matter what. That kind of makes sense that even though the hoses to each are the same size, off the same pump, that smaller aft condenser has smaller tibes and passes less.

Anyway now that I have the circ pump and fittings it isn't a big job to repeat when needed.
 
Oct 29, 2016
1,703
Hunter 41 DS Port Huron
Interesting observation, perhaps a finer screen in the inlet seawater strainer, although that may become a big pain in the butt. I never use the aft unit, it too noisy when putting down for the evening, the cycling is also too much. I just put a clamp on fan in the passageway and move air in from the main cabin.
Just got the boat back in the water from the winter layup, figures here in MI the weather went from 40's&50"s to 90's almost in the same week, I was down at the boat yesterday cleaning and I went to open the valve for the AC and notice water running from the hose, seems when they winterized the boat they never retightened the clamps on the line, sure glad I saw the water when I initially opened the valve.
This prompted me to check on the clamps on all the line from through hull valves.
 
Jan 12, 2011
930
Hunter 410 full time cruiser
2 years ago i had a problem with the aft and hooked up dock water to the system and shut the forward outlet. Open dock water and since the aft was clogged the system pressurized and the hose for the forward outlet blew off. Turns out that the clamps werent even tightenng the hose on the bard. Nothing was holding the hose to the fitting.

At time boat was 18 years old and i had had it 8 years. So probably it had been that way always