Fresh Water Pump runs non-stop

[Pilot]

All:

I have a 2008 350 who's freshwater pump runs constantly when the circuit is turned on. The water pressure is also sporadic.

I've checked and tightened all of the screws, but none were loose enough to seem like they were causing the problem. It did stay off after I recently filled the water tank, but, after a couple flushes and running the faucet, it stuck on again.

Has anyone had this problem? It's also loud from vibrating on the mounting.

Thanks

 

[carterchapman]

My dock mate has an '06 340 and his freshwater pump would not cut off. After checking for leaks (none), we found an adjustment screw on the pressure switch end of the pump. We unscrewed the adjuster a couple of turns and the pump now works "as advertised".

 

[Southpaw II]

Check the inlet strainer on the pump for bubbles while it's running. If you see bubbles, you're sucking air probably from a cracked plastic fitting on the inlet side of the pump.

 

[Pilot]

Check the inlet strainer on the pump for bubbles while it's running. If you see bubbles, you're sucking air probably from a cracked plastic fitting on the inlet side of the pump.

Thanks, I'll check the strainer and see what I find.

 

[Pilot]

Thanks. I didn't see any adjustment screw, but I'll take a closer look and see if there's anything. Maybe even the manufacturer has some specs for the thing on line.

 

[boatmailster]

All:

I have a 2008 350 who's freshwater pump runs constantly when the circuit is turned on. The water pressure is also sporadic.

I've checked and tightened all of the screws, but none were loose enough to seem like they were causing the problem. It did stay off after I recently filled the water tank, but, after a couple flushes and running the faucet, it stuck on again.

Has anyone had this problem? It's also loud from vibrating on the mounting.

Thanks

check for opened drain valve and pressure relief valve on water heater
they may drain directly overboard and you can't see any water leaks

 

[johnsross3]

I'd also suggest making certain all your fittings to the pump are tight. I had the same problem and found that it was struggling to attain the correct pressure due to air leaks from fitting that had loosened up a bit. Given that you mention the vibration noise, that vibration could very well loosen the fittings a bit over time. Good luck!

 

[tjbaze]

My 460 has dual pumps in line, I found if i drained water from a point lower than the pumps, air would come out and solve the problem for a bit. After closer examination I found a slight leak on the intake side causing the air bubbles thus the pressure drop...Hope this helps

 

[Pilot]

Thanks All! I think this will give me enough ammo to diagnose the problem. I'll let you know what I find.

Cheers

 

[Dave S]

I had the same problem on my 260DA when it was new. It was a faulty pressure switch which would not allow the pump to turn off and the whole pump was replaced under warranty.

Dave

 

[Mr Salt]

We encountered a simplier problem, but it turned out to be a bad pressure relief value on the hot water heater. The valve opened at too low a pressure and the pump kept trying to fill the tank.