Shower Sump Pump Not Working

[tonyhays]

I have never had need to use the shower sump/refrigerator drain pump (Jabsco Par Max 3) except for brief testing to verify that it worked (it did). It is located under the galley sink.  Recently I had to drain some ice water from the refrigerator but the pump no longer worked. First I changed the 5A circuit breaker, but that didn't solve the problem, so the next test was to see whether voltage was getting to the motor. To do that I had to take the cover off the end of the motor, which revealed that it had been improperly wired.  One of the wires was about two inches too long, and the extra loop had been stuffed into the motor.  This loop had touched the rotor, so that when the motor was operated the wiring insulation was very quickly abraded which proceeded to short the armature.  I can only surmise that the POs had never used the pump.  The solution should be easy - shorten the wire to remove the loop (including the abraded section) and resolder to the motor terminal.  The problem is that there is now no continuity between the wire at the output of the panel circuit breaker and the end of the wire at the motor (or rather at the abraded section where the wire is visible).  My question is - is there another fuse or circuit breaker somewhere in the wiring between the panel circuit breaker and the motor? The wiring diagrams on pages 36-37 of the Owner's Manual show a continuous wire between the panel and the motor, but a continuity test shows an open circuit. What should I try next?

[Stu Jackson]

What should I try next?

Get some wire, add a fuse and run it from the battery terminals to the pump.

[tonyhays]

Hi Stu - I'm sure your suggestion would get the motor to work, but I'm looking for a solution that would restore the ship's wiring to its original state, or something very close to it. I think that that would require finding out why the wire from the circuit breaker to the motor has lost continuity.

[Stu Jackson]

Well, then, there's only one other thing to do, right?    ITWMB, I'd simply trace the wire all the way back.  It's not that far...  I've done it myself, many times.  No telling where it could have gotten dinged.  If it's electrical it's either the wiring or the connections, and 99% of the time it's the latter. Good luck.

[tonyhays]

The wire runs in black corrugated plastic conduit. How do I trace the wire back without slicing the conduit open?

[Ron Hill]

Tony : Are both the positive and the ground wires showing no continuity?
 
If so you can use the present wires as a tracer, attach 2 new wires and pull them thru the inside of the conduit.

A thought

[tonyhays]

I'll give it a try.  Thanks for your suggestions

[Stu Jackson]

Tony, I hear ya.  I'm very glad our boat is old enough ( ) to not have those conduits.  I've always found them to create more problems than they solve, just as in your case.

You can either use Ron's idea, which is quite good, or just run new wires outside the conduit and wire tie them to the conduit.  The + & - wiring is also available in duplex wiring with its own covering.  While more expensive than single wires, it's a neater solution, and I'd guess you maybe have all of 15 feet to deal with.  You could abandon the old wiring and clearly label it, or pull it out.

Before running it, you could use it to connect to the panel and run to the pump and try it out first.  That's what I'd do and have done.

Good luck.

[tonyhays]

Currently I'm at home and the boat is about 40 miles away.  Do you know offhand what gauge wire I should buy?

[Stu Jackson]

Tony,

I've found these helpful:  http://www.westmarine.com/WestAdvisor/Marine-Wire-Size-And-Ampacity

Motor amperage is most likely anywhere from 4 to 10 amps.  10A for 20 feet is 12 gauge.  Sounds right.  ITWMB, I'd check on 10 gauge and then as always check the wire fuse size required.

Like this:  Blue Sea Tables  https://www.bluesea.com/support/reference

Scroll down to find the PDF download:  Correct Size Wire & Fuse Chart.  Handy to keep around.

[KWKloeber]

Currently I'm at home and the boat is about 40 miles away.  Do you know offhand what gauge wire I should buy?

Tony,

There's two aspects to correct wire sizing --

(1) the amperage that the wire size can handle (i.e. keeping the wire cool enough so that the insulation doesn't melt -- it doesn't matter whether the run is 1-foot or 100-feet,) and

(2) the voltage loss of the run.  (i.e., is there enough voltage left over to power the equipment, light, etc. -- the loss is proportional to the length of the run.)

Typically, (2) voltage loss -- is the controlling factor.  e.g., for a 10-amp load, single conductors (not bundled), outside the heat of the engine space -- 18-AWG is plenty to handle 10 amps.  It doesn't matter the length of the run.  However, voltage loss for 10 amps, 30-feet total run (positive feed and negative return) is 2 volts or over 16-percent loss - unacceptable.

If you use 12-AWG, the loss is 1/2 volt, or 4%.  Acceptable, because it's not a critical circuit (such as nav. lights.)  But, if you pay a few pennies more for 10 awg, the loss is 2.3% or 0.3 volts.  Overkill?  Probably, but the way I look at it is --- if it's less than 10 bucks and it's a one-time purchase -- then I will overkill it just for peace of mine.  I try to keep any new wiring for critical circuits at < 1% voltage loss (ABYC allows 3% loss).  For lighting and other non-critical circuits, I like to keep it < 3% or 5% max (10% is allowed.)  Tinned copper is one of those things that I feel is a good investment on a boat and don't mind buying heavier than I absolutely need.

Here's a great interactive calculator for voltage loss:
www.bestboatwire.com/voltage-drop-calculator
Mike is the competition, but he is a good guy and also a very good source for wire, etc., at a reasonable price.

Note that yellow is the new black -- ABYC is recommending yellow as an alternate for grounds (negative returns) because confusing a black 120v positive conductor with a black 12v negative conductor can lead to disaster (not to mention death.)

Good luck.
Ken

[Ken Juul]

On my boat the fresh water pump must be turned on to get power to the shower sump pump.

[tonyhays]

Hi Ken -

That's very interesting, and nobody had mentioned that possibility before.  That would require that the circuit breakers be in series with the fresh water circuit breaker being upstream and carrying the load for both the fresh water pump and the shower sump pump. The shower sump pump breaker would have to be downstream and carrying the load for only the shower sump pump. That can't be the case for our boat because the downstream side of the circuit breaker for the shower sump pump is either live or not live depending on the position of the circuit breaker, independently of the fresh water pump circuit breaker.  The wire for the shower sump pump circuit breaker disappears into the black corrugated conduit and appears to emerge under the galley sink.  Other things may be happening behind the chart plotter at the nav station or under the cabin sole, but I can't figure out how to pull the chart plotter out to look behind it, and I don't think anything can be happening under the cabin sole because it's inaccessible. If anyone reading this can tell me how to remove the Raymarine Raychart 570 chart plotter, it would be appreciated.  The Raytheon manual isn't very helpful.

[Stu Jackson]

Tony,

Got a picture?

While Ken's may work like that, ours doesn't.  There are two separate breakers:  one for the water pressure, one for the "sump pump."  There is, of course, the separate switch in the head compartment for the pump.  Sump pump breaker ON the switch in the head compartment works the pump when showering.

That's what the wiring diagram in the manual shows, too.

"Under the galley sink..." has me confused.  Do you mean under the head?

[tonyhays]

For anyone following this thread from the beginning, I can report that I carried out the first step outlined in my first post.  I took the motor/pump assembly home, shortened the power leads to remove the abraded sections, resoldered them to the small circuit board at the top end of the motor and successfully bench tested it.  So the only remaining issue is getting power back to the motor.