Bilge Pump Blew Up - Literally

[Swee Pea]

Couldn't figure out why my Rule Mate 1100 Bilge Pump would not work. Checked the fuse in the lazarette (10 amp) and it was blown. Every time I replaced it with a 10 amp, it blew. Tried to trace wires, no visual breaks. Called a local mechanic who came by. Replaced the fuse with a 20 amp. Still not working, but did not blow the fuse. He used a tester to see the pump was getting juice. Removed the pump and the impeller not turning. A piece of debris way up behind the impeller - dug it out, impeller turned. Then BAM, like a firecracker, blew the top off the bilge pump. Stink! Burned up bilge pump.

Gotta get another pump. (No Duh!) Wonder what the cause was? I asked about that 20 amp fuse, but the mechanic said that was not the problem.

I'm a dummy, I don't know. Ordered a new pump. Maybe some of you all's insight will help edumacate me a little, before we burn another one up.

John
Swee Pea

[Sea Wolf]

John-

The problem was most probably that the current into the motor had heated up the armature at the brushes, melted the solder, and jammed the armature copper contacts against the brushes. The armature was at that point not round and could not turn.

This happened either because of the initial blockage, or when the larger fuse was added, and the current left on.

He might have said the larger fuse was not the problem to avoid the responsibility factor. How long was the current left on with the 20 amp fuse in place?

Fuses are there and in a specified size for at least two reasons, first to protect the component fused from overloads, and secondly, to prevent electrically induced fires.

Next time try to test the pump to see if the impeller will turn (along with the motor) before going to a larger fuse, and then only use the larger fuse for a few seconds, understanding that the larger fuse can cause additional damage itself.

Joe.

[Wandering Sagebrush]

John,

I don't know if the 20amp fuse was the cause of the problem, but I think you should go back and kick your boat mechanic square in the a$$. Let him walk around with his butt between his shoulder blades for a while.

Putting oversize fuses and circuit breakers in is not safe, and could conceivably melt some wiring...

Steve

[mjsiega]

Your boat mechanic should be referred to as your former boat mechanic. Only use the fuses the device is specified for. A stalled or jammed motor draws a whole lot of current as there is no back emf to oppose the current flow. More than likely if the 10 amp fuse is the correct fuse for that motor, then no damage was caused when the 10 amp fuse blew. Can't say the same with using a 20 amp one.

-Mark

[Walldog]

The big problem is not the pump, as it was probably toast already. The problem is the wiring from the source to the pump, that may have been stressed by the overload. It should be examined for evidence of over heating.

[Swee Pea]

That's what I kinda thought. I will put back a 10 amp and see what happens.

Sometimes I think that I am the least qualified person to own a boat; I am not a mechanic, an electrician, or a certified Captain. I like my C-Dory because it is a simple boat. Hah! Just look at that nest of wires behind the wire cover in the berth area. Add the fuel systems, complex motors, steering cables, ELECTRONICS, Wallas stove, electrical system, charging system, etc., etc. I feel like I am at the mercy of others ... and get bad advice from the local talent in my area.

But I wouldn't trade or sell my boat for anything, nor trade the friendships of this site for the so-called local experts. I need to develop some patience and give you guys some time to "bail me out".

Thanks guys (and gals)

John
Swee Pea

[AstoriaDave]

John,

It's one thing to be ignorant, as you are about some things. It is another to have been exposed to the right way to do things and then be stupid enough to ignore that knowledge and do what your "mechanic" did.

It is hard to fix stupid. Not difficult to fix ignorance. You'll pick stuff up incrementally as you go along. That's all anybody ever does.

And, in the morning, we all put our pants on: one ... leg ... at ... a ... time!

You might find it useful to pick up a copy of Nigel Calder's Boatowner's Mechanical and Electrical Manual and keep it handy for the next time something goes bozo. No need to try to digest that tome without a context or a need, but if you have it handy, you will absorb stuff as you need it. Link: http://www.amazon.com/Boatowners-Mechanical-Electrical-Manual-Essential/dp/007009618X

[Noreaster]

Your "ex-mechanic" teaches a lesson I learned years ago in electronics school: never fuse a circuit with a fuse larger than the origional. The fuses primary function is to protect the wiring. You should absolutly inspect the wire to make sure it is still intact. You will be looking for obvios signs like melted or burned insulation. Hopefully, you have no more hassel than replacing your pump, If you do find your pump circuit wires are damaged be sure to check adjacent wiring for damage also, Good Luck.

[richnkay]

Last week I went to my boat and heard the bilge pump running when I stepped aboard. I opened the hatch and saw the bilge was dry but the pump continued to run. The pump, a Rule-Mate 1100 gph had one of those sealed automatic water sensor switch units on it. The pump continued to run even after I lifted it from the base. Long story short, as afternoon thunderstorms were forcast, I cut the wires and not being able to find a replacement locally, replaced it with the Rule-Mate 1100 from the cabin, this one having a movable floating type switch on it. I'll replace the cabin pump with one I ordered on line, with a floating switch.

I guess the sealed water sensors cause the pump to become a throw away once they go bad. Anyone else have problems with this type of automatic switch or have a preference to other automatic bilge pumps and switches?

Rich, Central NY

[Sea Wolf]

[tpbrady]

I had the same problem with the pump under the step in my 25 designed to pump the cabin. One day it started running while I was there. It does have an internal float switch as it is wired with 3 wires. One hot to the battery, one to the switch at the helm, and ground. Not know which to cut to stop it, I elected to do the ground until I could determine whether to cut the brown wire or brown/white wire. I now have a manually switched pump. I think I will add an external float switch sometime in the near future.

[richnkay]

Joe,

Thanks for your comments, I kept the pump, hate throwing away things that even kinda work. I think I will take it apart for a look and if I don't mess it up too badly during the disection re-work it and keep it around as an emergency spare.

Rich

[Swee Pea]

I replaced the annoying "every two minute" bilge pump with a Rule 1100 Automatic (built in float) and it worked for more than three years without a glitch. I am sure your diagnosis is correct: debris clogging the impeller and overheating/too much resistance/ weakening the pump. A 20 amp fuse helped fry the pump. But that thing blew like a firecracker.

I will install a new pump with a 10 amp fuse and see if I can figure out a better way to keep debris out. Wiring seems fine.

Thanks for all your input.

John
Swee Pea

P.S. Astoria Dave: I prefer the term "uninformed" rather than ignorant. I hear your point.

[breausaw]

Dang, I have the same pump. Been procrastinating about purchasing a backup other than the old hand pump, guess I’ll be making a visit to WM. We were stuck up in a cove last weekend while a storm moved in off the Gulf of Alaska, 36hr on the hook. The rain was relentlessly and we had left our side curtains in the truck. The bilge pump was coming on a lot and was thinking it would really be a drag if I had to hand pump the cockpit periodically throughout the night.

Sometimes if the outboard is running I can’t hear the pump when it is trying to pump and nothing is coming out, that’s how these things get burned up as others have said. Best to make sure things are working well before bedding down for the night.

[Tim & Dave Kinghorn]

Most bilge pumps are labeled with the current draw and the recommended fuse size (usually a couple of amps higher). The idea is that if the pump seizes, the increase in current draw will blow the fuse; but if the fuse is too high a value (and 10amps sounds high), the pump will overheat and possibly catch on fire. Additionally, if the wire size feeding the pump is too small for the run (and most are), the resistance of the line can defeat the safety of the fuse with the overload. Generally, I've seen the fuse recommended to be around 6-8 amps. I would wonder if a 10 amp fuse might be too high to blow if the motor seizes.

Tim & Dave Kinghorn