Fresh water pump runs constantly when switched on even with faucets closed


Seaduction

Seaduction

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The fresh water pump on my 2012 310SS runs constantly when switched on at the D/C panel, even though no faucets are open. Any idea what is causing this?

Faucets are rarely, if ever, used. Head and aft shower are the main fresh water uses.

I have checked every line everywhere and cannot find any leaks. I did find that the fresh water sump box pump is not working, causing water to fill up in the sump box (attached) and spill out into the cabin crawl space. Could this be causing the pump to run constantly?
 

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The pump is an auto-shut off type. So the shut off sensor is not working. Best to replace the pump. The sump would be a separate issue.
 
Regarding the gray water sump box. Mine too had the same issue. It was the float switch. And raising the float manually didn't complete the circuit either.


Seaduction said:
The fresh water pump on my 2012 310SS runs constantly when switched on at the D/C panel, even though no faucets are open. Any idea what is causing this?

Faucets are rarely, if ever, used. Head and aft shower are the main fresh water uses.

I have checked every line everywhere and cannot find any leaks. I did find that the fresh water sump box pump is not working, causing water to fill up in the sump box (attached) and spill out into the cabin crawl space. Could this be causing the pump to run constantly?
Click to expand...
 
Seaduction said:
The fresh water pump on my 2012 310SS runs constantly when switched on at the D/C panel, even though no faucets are open. Any idea what is causing this?

Faucets are rarely, if ever, used. Head and aft shower are the main fresh water uses.

I have checked every line everywhere and cannot find any leaks. I did find that the fresh water sump box pump is not working, causing water to fill up in the sump box (attached) and spill out into the cabin crawl space. Could this be causing the pump to run constantly?
Click to expand...

So few basic questions.

1) you MIGHT have a bit of air in the lines, can you open all faucets while on DC and make sure you get a steady stream out of all, turning them on / off to verify.

2) then it MIGHT be the sensor as above, or you MIGHT have a leak where it is not noticeable (yet) - but most likely the sensor.

3) as for the sump box, the float likes to stick or go bad...so assuming you have power to it, most likely the float.
 
Is the tank losing water? Sometimes the solenoid for the single point fill/city dock water does not seal and it just recirculating water out of tank and back in....remove it and clean.
 
Will try the on/off on each line to see if that corrects the problem.

Tank is losing water, so that seems fine.

Have checked all lines for leaks, none found but will check again.

Formula TAG says a bad shower sump box pump would not cause the fresh water pump to continuously run. Sump box pump is not working so I've ordered a new one to replace.

Boat is only 5 years old and fresh water pump is rarely used, so you would think the pump is fairly new....but maybe I've got a lemon.
 
Seaduction said:
Will try the on/off on each line to see if that corrects the problem.

Tank is losing water, so that seems fine.

Have checked all lines for leaks, none found but will check again.

Formula TAG says a bad shower sump box pump would not cause the fresh water pump to continuously run. Sump box pump is not working so I've ordered a new one to replace.

Boat is only 5 years old and fresh water pump is rarely used, so you would think the pump is fairly new....but maybe I've got a lemon.
Click to expand...


Just to be clear, assume tank is ONLY losing water while the faucets are opening....meaning it is not losing water while the pump is running on DC (thus a hidden leak)
 
Now, the fresh water sump pump is bad so need to replace this weekend before I can test all water lines.

Interesting that my shower drain line on my 310SS does not feed to the sump box, but appears to drain to the engine bilge. Is your boat set up the same way?
 
Seaduction said:
Now, the fresh water sump pump is bad so need to replace this weekend before I can test all water lines.

Interesting that my shower drain line on my 310SS does not feed to the sump box, but appears to drain to the engine bilge. Is your boat set up the same way?
Click to expand...

Well for sure mine is not, and that seems strange, but others with an SS will have to chime in.
 
On my 330SS it drains in the shower sump box. It should not drain into the bilge...that would be a lot of water. Replacing that shower sump box is a royal PITA if you have a generator.
 
My mistake...shower does drain to the sump box. The line that I saw was the cabin door drain that runs to the bilge. Easier to see where the lines go once I climbed into cabin crawl space...fun area to work in! :)

I replaced the sump box motor today. Left the current box in place since it was fine and had 5 hoses connected to it. Interesting that the sump box does not drain completely. Takes almost 2 inches of water to trigger the float "on" switch.
 
Forgot to add regarding the fresh water pump....opened all faucets to make sure there was no air in the lines that would cause the fresh water pump to keep running after water is shut off. Everything had great water pressure including both all 3 sinks, cabin shower, aft shower and head.

Interesting that when I ran the tank down to empty, the fresh water pump shut off. I refilled the fresh water tank and turned on a few faucets, then shut them off...fresh water pump continued to run so I just shut it off at the breaker.

As mentioned above, there must be a leak somewhere but I have not been able to find it. This pump will be a real PITA to replace since it is very difficult to reach.

Any other thoughts as to what might be causing this?
 
Do you have any fresh water in the bilge? Clean your strainer? All plumbing runs on the port side, maybe pull frig out and push red and blue and make sure they are pushed in to connectors.
 
This may sound odd - but do you have a fresh water wash down for your anchor? Do you keep the hose connected to it? Happened to me a few years ago on a 37PC. where the pump kept running but I could not find water anywhere. I opened the anchor locker and voila! The hose had somehow sprung a leak and was enough water to keep the pump running. Water was going into the chain locker so that is why I never found water anywhere. Just a thought.
 
No water in bilge, strainer is clean. Red and blue connectors on port side checked and under galley sink checked, no leaks.

No anchor wash down on my boat, but thanks for the suggestion.

About the only connectors I have not checked, which I cannot get to, are leading to the Head and Head sink.

It may be that the fresh water pump's auto shut off is not working, so rather than replace the water pump which will be a real pain, I may just shut the pump off after each use and just live with it.
 
Sounds like the pump. There is a vent hole on top of the pump, if I remember correctly, that needs to be free and clear. check that first. If you don't have any leaks, has to be an or leak somewhere in line. The only other things to check are the expansion tank and filter. They are right next to the pump. Maybe sucking air around the fittings.

Dave
 
I replaced my pump, expansion chamber and filter last year and added the "quiet kit". Made a difference, might want to think about it while you are in there.

Dave
 

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Thanks Dave! Will check the vent hole, expansion tank and fittings. Pump is difficult to reach since they positioned it more to the starboard side behind the a/c compressor.
 
Had the same problem. All was needed was a good brushing and cleanining to the pump and box. A really good cleaning. Has been working fine sincd.
 
Seaduction, et al ... how did your finally resolve this problem. I seem to have the exact same issue on my 2015 310SS. My troubleshooting points to pump pressure issue which is keeping the pump running and not tripping the internal pressure switch. I noticed pump was running full time today. Opened / closed all faucets. No evidence of leaks or air binding in the system. I did notice that pressure seemed to be less at faucets then past times. Seems to imply that pump isn't putting out full pressure and causing switch to continue to call for the pump to run. I know this is a 4 chamber diaphragm pump so I wonder if the diaphragm bladder is bad. Only thing different on the boat today vs. a month ago, is that it's been in the shop for sterndrive rebuild (posted elsewhere). Boat was on a trailer for a month but can't imagine how that caused problems, unless the trailer ride caused sediment in FW tank to get churned up. My issue is that the pump location, as on your 2012 310SS, takes a midget to access. And I don't know if you can get it without removing the A/C first. Pump's relatively cheap on Amazon - less than $100. Add in line filter for $8 and parts are reasonable. Labor on the other hand...unknown!! Interested in how you solved the issue or whether you simply switch the system off when you aren't using at the electrical panel.
 
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