A/C water line stopcock...

Mar 3, 2008
188
Hunter 356 Lake Stockton
After years of having to reprime the A/C water pump every spring, I have finally decided to install a stopcock in the exit line from the pump to simplify the process. However, I am 4 hours round trip from the boat and cannot find a reliable refence regarding the size of that line. I think it is 1/2" but I want to be certain.

Please share your knowledge on this question and you can rest assured that a cold KC Boulevard beer will be on hand for you upon your next visit to Lake Stockton, MO.
 
Sep 25, 2008
6,353
Alden 50 Sarasota, Florida
Consider that A/C equipment is installed at commissioning, not by Hunter. As such, there is no guarantee of uniformity

Also, if you run the pump with a valve closed in the exit line, it likely won't prevent an air lock in the iinfluent line. If se it did work and you ran the pump with the valve closed, it could blow a line or the pump itself because of back pressure.

You would do better installing it on the thruhull (where it belongs).
 
Mar 20, 2012
3,983
Cal 34-III, MacGregor 25 Salem, Oregon
Consider that A/C equipment is installed at commissioning, not by Hunter. As such, there is no guarantee of uniformity

Also, if you run the pump with a valve closed in the exit line, it likely won't prevent an air lock in the iinfluent line. If se it did work and you ran the pump with the valve closed, it could blow a line or the pump itself because of back pressure.

You would do better installing it on the thruhull (where it belongs).
I agree with Don... to prevent bleed back and loss of prime, it should be installed on the inlet line, NOT the exit line...
 

RichH

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Feb 14, 2005
4,773
Tayana 37 cutter; I20/M20 SCOWS Worton Creek, MD
Best way to correct for such a (March-type magnetic coupled) pump losing its 'prime' .... move the pump into a LOWER location from the static waterline - move it 'deeper' in the bilge, etc. This will help to insure that there is enough water (static head)in the hosing to overcome the startup vacuum/pressure differences and allow the pump to be 'self priming'.
 

splax

.
Nov 12, 2012
678
Hunter 34 Portsmouth
installing such a valve could also lead to problems regarding winterizing for freeze protection
 
Sep 15, 2009
6,242
S2 9.2a Fairhope Al
Best way to correct for such a (March-type magnetic coupled) pump losing its 'prime' .... move the pump into a LOWER location from the static waterline - move it 'deeper' in the bilge, etc. This will help to insure that there is enough water (static head)in the hosing to overcome the startup vacuum/pressure differences and allow the pump to be 'self priming'.
if done by the directions to begin with the pump should already be below the waterline i did this when i install my ac because these little pumps can't prime very well because of the they way they are designed it makes all the difference in the world if done correctly to begin with
 
Jun 5, 2004
138
HUNTER 450 Rockhall MD
I put a brass T and a pipe plug in on the outlet side of the pump. I open the seacock and remove plug and the pump is primed. It makes cleaning the filter much easier too
 
Jun 5, 2004
138
HUNTER 450 Rockhall MD
Too winterized I pump the coolent into the system this way with a cheep 12 volt pump I can see it come out the outlets,good luck
 
Mar 20, 2004
1,668
Hunter 356 and 216 Portland, ME
Hi Doug/Karen,
we added a mermaid marine A/C system to our 356 and they explicitly recommend adding a t and stopcock like Rtmccue to simplify priming. Works great, and I also use it to winterize the a/c by pumping antifreeze thru the system
 
May 13, 2011
420
Hunter 40.5 Legend Jupiter
This is how I did mine as I too was sick of it not priming

When I clean the filter I shut off the valve here and the SEACOCK then unscrew the filter

Once clean filter goes back on, seacock on to fill up filter then the valve is opened

Works every time in keeping my pump primed
 

Attachments

Jun 1, 2009
1,387
Hunter 49 toronto
I have to agree

+1 on below the water line. More valves more problems.
A correct install procedure is your best cure.
So having the pump as low as possible helps.
The March pumps have really bad suction with air locks.
On my 49 they used a higher quality Cal Marine pump.
I've only had it lose prime once, and it took 5 minutes to fix by unscrewing the filter.
I agree that adding more "stuff" is just adding more potential for winterizing issues, etc.
The point being, if it takes 10 minutes to prime once per season, that isn't on the top of my fixit list.
Years ago I was helping someone troubleshoot a Dufour with a March pump.
Problem was the through hull was installed in such a way that when the boat heeled over 20 degrees, the through hull was out of the water.
Tried everything including check valves. Finally had to "move" the through hull.
 
May 13, 2011
420
Hunter 40.5 Legend Jupiter
Unfortunately where my pump is is where it's staying due to the way it was installed - 'poorly'

However I have to say I've had the exact opposite experience pump wise. The Cal pumps I have found to be poor when it comes to corrosion and reliability - the march pump seems to be a lot better made or so it seems?

Even when I spoke to the main supplier here in Florida for both cal and March pumps they couldn't say anything positive about the cal pumps - apparently they used to be quality but not anymore (a Google search I did whilst replacing my 2nd cal showed similar responses)

As for winterizing - thankfully not needed where I am :)
 
May 16, 2007
1,509
Boatless ! 26 Ottawa, Ontario
We have T's on our though hulls. One side has the original hose the other a valve and a hose barb. The barb allows winterizing with antifreeze or in our case summerizing with Saltway. I keep a piece of hose on the barb for our AC. To prime it I just close the through hull, put the hose on our galley sink tap, open the valve, turn on the water. It only takes a minute. We usually only need to do it if the boat has been hauled.

Bob