Loss of prime for water

[tadd5181]

My boat is a 2000 Hunter 420. I often lose prime ... causing inability to draw water (for sink, heads)...the pump runs endlessly. I have tried a solution that has worked in the past: open all water valves, including the stern outside shower, all to no avail. I have checked that my 3 water tanks have water levels at full or at least above half full. And repair agency suggested it is because the pump is "above water level"...it's located under the starboard dining table seating and just forward of the nav table. The agency is suggesting relocating the pump below water (sea) level.

It's hard to believe Hunter misplaced the water pump and the it needs to be moved. That would involve a great amount of re-piping.

Any suggestions for regaining prime?

 

[Nodak7]

Tadd, we have a Hunter 41DS and it does the same thing on the Port Water tank. It just happens at times. I looked at all the connections and have never found an issue. Whoever told you that the pump being "above water level" was the problem has no clue. Most water pumps draw there water from a tank and 90% of the time it is located above the tank. Anyway I will watch this thread and if if any of the suggestions apply to my similar issue.

 

[twalker H260]

I would be looking for an air leak between the tank and the pump - assuming your sure the pump itself isn't leaking.

Likely above the waterline connections/line as you don't mention the water from the tanks being found in the bilge.

 

[Hardware]

I have a 2001 420 and the only time I had that problem I took the sight glass off of the strainer between the manifold and the pump, cleaned the strainer, then put everything back together and it worked great. Other times it has been because of an empty tank. Switch tanks and no problems. Sorry I'm not much help.
--Jim

 

[Terry Cox]

And repair agency suggested it is because the pump is "above water level".

Hi Tadd, bizarro assessment, IMHO. Different boat and water system here, but our potable water pump is above both tanks and the only time we have had a prime problem is either a:

1. Empty tank
2. Clogged spigot at the tank.
3. Clogged strainer that protects the pump.

 

[West Coast head ghost]

Hello try checking your tank vent line if it is clogged or plugged it will not allow the pump to draw water. Failing that.depending on the water pump type ,it could be a pressure switch or impeller problem. my guess is your tank that is plug

 

[West Coast head ghost]

Your tank vent is plugged. Every time a Boulder allows the water tank to flow through the air vent to know that it is full ,it is causing problems. even water sitting in the air vent hose can plug it.

 

[West Coast head ghost]

LOL not a boulder . was meant to say a boat owner.
damn voice text .
It's also possible that you have a shut-off valves in the tank line to pump which is been accidentally Beenclosed ,or there is a inline filter that is blocked.

 

[sea_casper]

Had similar problem on 2004 H33, replaced pump, no problem.
Replacement was about same cost as rebuild kits.
Your pump is older.