Marine AC

Private Nemo

Seaman
Joined
Nov 7, 2011
Messages
60
Since spring is around the corner , I am starting to think of the things I need to do.
My AC has a problem that I have not been able to solve. The water cooling pump loses pressure and does not circulate water, of course the AC shuts down. I thought it was the pump so I bought a brand new very expensive pump. Same problem. I check the lines all clear. If I take the intake line off the pump when it stops circulating , plenty of water comes thru the line, I could sink the boat pretty quick. Most time the pump will start to circulate again, for awhile.

any help is appreciated

Drew
 

agallant80

Commander
Joined
Oct 25, 2010
Messages
2,328
Re: Marine AC

My AC pump is not self priming and needs to be primed to work. If the water goes out then it just cycles on and off. I have two questions.

1. Is your pump self priming
2. If it is not self priming is it mounted above the waterline?

Mine is not self priming and is mounted above the water line. It will do what you describe if the prime goes out IE forget to close the seacock before I pull it from the water.
 

agallant80

Commander
Joined
Oct 25, 2010
Messages
2,328
Re: Marine AC

Another thought is to close the seacock, remove the line turn on the system and pour water down the line. If it works than the pump needs to be primed. This would work best with two people. You doing the water pouring and someone else turning the system on, though from what I know about marine AC is it will cycle off for about 30 sec if it does not detect water than cycle on again.
 

Private Nemo

Seaman
Joined
Nov 7, 2011
Messages
60
Re: Marine AC

Thanks for the replys. The pump is mounted below the water line and it is self priming. It does work when it wants to, then stops.
 

agallant80

Commander
Joined
Oct 25, 2010
Messages
2,328
Re: Marine AC

Could it be an electric issue? A sensor telling the pump to shut off. I have a portable jump pack which is usefull to bypass the electric. If you wan wire it directly to the battery or a jump pack you may be able to chase it down to a sensor or electrical issue. What model is the pump and AC unit?
 

boatpoker

Seaman Apprentice
Joined
Dec 29, 2008
Messages
46
Re: Marine AC

I'd put my money on an air leak somewhere between the seacock and the pump. Cracked hose - loose hose clamp - crack in the strainer, crack in the strainer cleanout cap, bad gasket in the strainer cleanout cap.
 

Private Nemo

Seaman
Joined
Nov 7, 2011
Messages
60
Re: Marine AC

Hi, Not an electrical problem. Motor keeps running, just loses water flow. Could be an air leak, I will check as soon as it warms up. But if an air leak, wouldn't water leak in when motor is not on.

Also dose the size of the strainer matter. I replace the strainer with the motor. It was old and corroded. The new one is half the size . Salesman at West marine said it would not be a problem.
 

boatpoker

Seaman Apprentice
Joined
Dec 29, 2008
Messages
46
Re: Marine AC

Hi, Not an electrical problem. Motor keeps running, just loses water flow. Could be an air leak, I will check as soon as it warms up. But if an air leak, wouldn't water leak in when motor is not on.

Also dose the size of the strainer matter. I replace the strainer with the motor. It was old and corroded. The new one is half the size . Salesman at West marine said it would not be a problem.

Not seeing any water leak with the pump off - could be a very small leak that opens slightly under pressure or suction. it only take a few bubbles to cause problems. If the strainer is too small it might be restricting water flow.
 
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