What size fuse for auto bilge

[Boris the Tug]

The fuse blew on my automatic bilge wire during all the rainfall here in California. Took on a bit of water before I got to it.

The blown fuse was 3 amp. Is that the right capacity for the bilge wire? Also is there anything I can do help prevent that in the future. I’m guessing the pump was working overtime with all the downpour we were getting every day.

 

[Martin610]

The fuse may have been simply doing its job. It's there to protect the wire.

With a bilge pump sometimes debris will jam the impeller or something causing the motor to draw more amperage and causing the fuse to blow. That's what should happen.

To check the draw, you could put a meter on the wire and turn the pump on. It has to be a meter that measures DC amps, not all of them do. Someone at your marina may have one, or you could call a tech. If the draw is 2.4 amps or less you are probably good with a 3 amp fuse. Opinions vary on the head room.

Fluid Motion's electrical installations seem pretty good to me, so it's likely you have the right fuse. You shouldn't increase the value without taking into account the gauge of the wire and the rating for the pump. I would also check the bilge pump for good working order.

 

[trailertrawlerkismet]

On our R29S the spade fuse is 5 amps but I’d suggest checking your manual or fellow R21 owner. As stated by Martin610 it may just have been doing its job. On our boat I apply some preventative maintenance, and you may already be doing this but if not read on. Periodically I rinse down the bilge, clean the activation sensors with a rag sprayed with a cleaner like Fantastic to clean any scum off so it works properly. I’ll also detach the pump, on our boat, from it’s housing and clean the housing out of any debris as well as the impeller on the pump. It all helps but may have nothing to do with your situation.

Jim

 

[Newf]

I have the 750GPH Johnson model in my 2014 R21EC. It calls for a 5 amp fuse. I'm on my 3rd pump/sensor combo. First one failed on 2nd or 3rd trip out and was replaced under warranty. 2nd one failed a couple of years later when it stayed on and fried the pump and sensor. The fuse and a bit of wiring also melted so I think an oversized fuse may have been installed on the warranty repair. ( Photos in my album) As noted in previous post its important to clean the sensor every now and again.

 

[Automaticman865]

I ran into the same problem like this with a pump sensor that started blowing fuses (5 amp). Spoke to the manufacturers switch and pump. Their recommendation was to replace the pump. Due to its getting older, and although it seems to work fine, they said the startup cycle starts producing larger spikes and those were what was blowing the fuses. We replaced the pump and all has been good since.

Stuart

 

[bill46]

My 31 shows 5 or 7.5 fuse, 5a breaker for manualfor pumps.

 

[Boris the Tug]

Sounds like I should take the pump out and clean it inside and out. I need to take it out anyway to see the manufacturer/model. The owner's manual doesn't show anything so I'll go by that model number and make sure I'm using the right fuse and wire.

Thanks for the ideas.

 

[Boris the Tug]

The fuse may have been simply doing its job. It's there to protect the wire.

With a bilge pump sometimes debris will jam the impeller or something causing the motor to draw more amperage and causing the fuse to blow. That's what should happen.

Sounds like it was just doing it’s job indeed. I removed the bilge and cleaned out all the debiris and degreased all the muck. Put in a 5 amp fuse and so far it’s working great.

Fluid Motion's electrical installations seem pretty good to me, so it's likely you have the right fuse. You shouldn't increase the value without taking into account the gauge of the wire and the rating for the pump. I would also check the bilge pump for good working order.

The pump is a Johnson 550 GPH model: 0550 with a model 2855 cartridge. It says right on the label to “use 5 amp fuse”, and “draws 2.5 amp” Not sure if that still holds true for the auto bilge wire to the starting battery, and taking into account the gauge of the wire like you mentioned. All I know now is the 3 amp is still blowing fuse after bilge starts pumping water for about 1 second. And the 5 amp is working perfect for now, I’ll keep an eye on it, thanks for the help!!

 

[Boris the Tug]

On our R29S the spade fuse is 5 amps but I’d suggest checking your manual or fellow R21 owner. As stated by Martin610 it may just have been doing its job. On our boat I apply some preventative maintenance, and you may already be doing this but if not read on. Periodically I rinse down the bilge, clean the activation sensors with a rag sprayed with a cleaner like Fantastic to clean any scum off so it works properly. I’ll also detach the pump, on our boat, from it’s housing and clean the housing out of any debris as well as the impeller on the pump. It all helps but may have nothing to do with your situation.

Thanks Trawler/ May I ask what are you referring to when you say activation sensors? I have an R21 and it uses a little Johnson bilge pump with a float valve. I took out the pump and float valve to clean them, but I could not get up inside where the float valve makes contact. I just sprayed some degreaser up in that area a few times. Is that the sensor you’re referring to? Maybe the bigger boats have A different kind of sensor.

 

[Boris the Tug]

I ran into the same problem like this with a pump sensor that started blowing fuses (5 amp). Spoke to the manufacturers switch and pump. Their recommendation was to replace the pump. Due to its getting older, and although it seems to work fine, they said the startup cycle starts producing larger spikes and those were what was blowing the fuses. We replaced the pump and all has been good since.

I have the 750GPH Johnson model in my 2014 R21EC. It calls for a 5 amp fuse. I'm on my 3rd pump/sensor combo. First one failed on 2nd or 3rd trip out and was replaced under warranty. 2nd one failed a couple of years later when it stayed on and fried the pump and sensor. The fuse and a bit of wiring also melted so I think an oversized fuse may have been installed.

Did you ever try just replacing the pump cartridge, or did you always replace the float valve as well? I noticed I can purchase those separately. At the very least these points are reason enough to pick up a spare cartridge for 25 bucks. With the float valve and casing included though, it runs a little bit more.