NC11 Bilge Pumps

[relaxsantabarbara]

Reposting this under "Motorboat specific" because i got no replies under "Equipment and Commissioning"...

I am new to my 2016 NC11. There's something wrong with one of my bilge pumps. When i flip the 2nd rocker switch at the helm, instead of hearing the pumping noise, i hear a buzzy-alarm sound (coming from the switch itself i believe).

• How do i go about troubleshooting this?

• Knowing that bilge pumps and float switches often "go bad", i'd like to get to know how many the NC11 employs, and where exactly do i find them?

Thank you,
John

[rene460]

Hi Relaxsantabarbara,  I am as surprised as you that no one seems to have replied on this one.

I can’t answer specifically what your model has, though I would expect it has the same bilge pump system as most boats of that size.  My SO30i has an electric motor driven pump with a built in level switch, plus a Manual pump operated from the cockpit.  The control of the electric driven pump is a single switch with three positions, on, off and automatic.  The automatic position supplies power to the pump through the level switch which is built into the pump body.

The piping on the pump outlet runs overboard through a through hull fitting.  The inlet side does not have a filter for either pump.  I suspect it would be better to fit one, though the bilge in my boat is pretty clean, so I don’t worry too much.  Our boat is quite dry in the bilges though there is always a little water entry when I insert and remove the log.  But I then mop it out once the log or the plug is in place.    But generally the bilge of any boat has an atmosphere likely to encourage corrosion, almost certainly the reason those level switches included in the pump do not have a good reputation for reliability.  

The pump inlet pipe configuration is not very effective at pumping out the last bit of water, and because there is no check valve (probably avoids another potential blockage point) the water in part of the discharge pipe runs back into the bilge when the pump stops.  The discharge point generally runs up to near the underside of the deck then back down to the outlet.  This is to stop water entry from the outside flowing in through the pump piping.

It is a matter of lifting the floor boards and looking around, I am sure you will find the pump near the lowest point of the hull.  And you will find the ends of the inlet points.  And your switchboard will have a switch for the bilge pump, again should not be hard to find.  It is unlikely that there would be two pumps on one switch.  Equally, two switches would indicate two pumps.  Your wiring diagrams will also tell you how many pumps are installed.

I would expect that if there is a manual pump the handle will be found in the sides of the aft cockpit.

Once you find the pump, it is possible to devise a test, which in principle should be done regularly, but I wonder how many people actually do this.  Disconnecting the hose, Lifting the pump out and using a bucket or dish is probably the best way to test it without making too much mess.  Main thing to check is that you hear the pump start when you flick the switch to the on position, but only run it for a few seconds as it is not intended to run dry.  If you are concerned about reliability of the float switch, I would purchase a separate float switch, and modify the wiring so either the built in or the separate float will start the pump.  Make provision to test your separate switch.  

We leave all the power switches off when we leave the boat as advised by the Jeanneau agent, so I am not sure that the automatic function will ever be important to us.  What to do about bilge pumps when you are away is another of those never ending questions.

I am wondering if the noise you are hearing is the pump running dry, or is it a faulty level switch not allowing it to run normally when in the automatic position.  Do the switch labels give a clue to what they are for?  Are the two switches two pumps, or one switching the pump on and the other through the level switch?

I hope that addresses what you are thinking about, or maybe you had a more specific question?

rene460

[richardc1]

Just following up to see if others have this same issue or any suggestions? My NC11 has the same buzzing noise from the right hand bilge switch. Sounds more like an electrical issue than an intentional sound.
Thanks, Richard.

[sjgoodwin]

Hi John.  Did u get an answer? I have a 2011 Nc 11. The rear bilge is under and between the engines.  That's the one likely on the right hand switch. The other bilge is under the bed in guest cabin. 

[inewbie]

Ha, now mine too (2016 NC 11)!

The right hand switch (to the rear bilge) intermittently (and/or when I rock the switch) sounds that buzzy sound and lights up despite the bilge being dry(confirmed by direct inspection and the absence of water being pumped over board).

The left switch to the forward bilge seems to operate normally as I can hear a motor hum when activating it.

Pretty tight quarters down there by the aft pump....but I might try to bring it out for inspection in the next month. If I learn anything I will report back (though I am mechanically dis-inclinded and pretty hopeless in such regards).

Thanks to Rene above for the great system discription.

Mike

[chris200]

Unless I'm mistaken, that switch that makes the noise is actually testing the high water alarm, not operating a bilge pump. That's the noise you will hear if the water ever gets up and over the bilge pump to the 'Oh nuts' level - it just gives you confidence that the alarm is working.