Bilge Fans - independent or ganged

[vtcats]

Speaking of bilge fans, I spent maybe 2 hours today twisted like a pretzel attempting to replace one of my 4 I have on the boat. I’ve come to the conclusion it will be easier to cut a 2x2 hole in the side of the boat, darn it. Joking aside
I may have to remove the large diesel fuel hose that connects right there at the tank. It’s the main thing preventing me from getting both arms/hands into that space on the side.
Stretching and twisting and using mostly one hand goes only so far. Had to give up (for now) with one side side of the connection point still attached and one end of the bilge hose disconnected.

[KyleR]

The issue is that the Fan #1 circuit breaker has to carry the load of all 4 fans (because of the ganging), and it pops when all four fans are running. Any combination of 3 fans (e.g., #1, 2, 3, or #1, 2, 4, etc...always requiring #1 to be on), will run without problem.

Just to let you know what I found out about this. The fans are not ganged, each having own independent power. However the power from Fan #1 activates a relay on all of the fans to allow the master fan switch to work. So, Fan #1 needs to be on to allow any fan to be on, but not all power is running through the Fan #1 circuit.

Okay - I realize this thread is super old - but when I read through it the one question I didn't see answered was about the "4th" fan breaker tripping when all four fans are running. The OP did later state that Fan #1 is not carrying all the load as initially thought and that it was a relay that Fan #1 actuated to allow the other fans to run. Just curious if you ever determined why the "4th" fan that got turned on would trip its breaker? Thanks!

[Midnightsun]

Probable causes are a seized bearing or worn out #4 blower or short on #4 wiring.

[KyleR]

I considered about the seized bearing but in the OP's examples he actually says "(e.g., #1, 2, 3, or #1, 2, 4, etc...always requiring #1 to be on), will run without problem."

That indicates that all four fans are working - they just can't be run at the same time.

[paulr]

I have a newly aquired 2001 396. The marine surveyor ripped this boat up pretty good because he could'nt find the forward or aft bidlge pumps. hopefully someone can tell me how to access them for testing.
Thanks

[Phrancus]

you may want to start a new topic about your bilge pump quest. This is an old topic.

[Crawfde]

I have a 460 Voyager and none of the blowers are operational and, as has been stated, getting to them is near impossible for an average man. Any suggestions on where to start looking for the relay location? if they are "near" the blowers I am ready to add new blowers and relocate them to be more accessible. Thanks in advance.

[Jskhome62]

Hello all. Hoping this post was active recently enough to get a response to this. Doesn’t quite address what I want some help with but seems close enough.

First, I finally got around to getting all 4 bilge blowers working on my 2003 360 SS. They are ganged electrically together through the relays described here but the difference seems to be they do not come on automatically with the ignition. I have a switch at the helm and one in the main salon panel - either of which will turn on the blowers whether the ignition is on or not. And once turned on from either switch, that is the only switch that will turn them off again, no matter what I do with the other. The only thing that seems to change is the salon panel switch lights green when I turn on from there and yellow when I use the switch at the helm. This isn’t really a problem for me as I typically run the blowers before and while I’m underway, but I’m curious if this may indicate some other wiring issue?

The other question is related to the hoses connected to the blowers. The ‘inboard’ blowers on both the port and starboard are connected to hoses that go to vents on the outside of the hull - makes sense if you’re trying to exhaust the fumes in the engine bilge. The ‘outboard’ blower hoses just run forward and hang open in the front of the engine room near the forward bulkhead. So seems like maybe these are circulating air from near the intakes of the exhaust blowers forward instead of exhausting to the outside. Kind of makes sense but would think they should be connected to something external. Is this normal or has one of the prior owners disconnected something they shouldn’t have and if so, where does the open end of the hose go?

Lastly, I think I e of these posts referenced ‘a sticky’ in the electrical forum. Does this mean there are wiring diagrams posted someplace?

Appreciate any help as always.

[bud37]

Source of the post Hello all. Hoping this post was active recently enough to get a response to this. Doesn’t quite address what I want some help with but seems close enough.

Is your boat gas or diesel ?

[Jskhome62]

Gas engines. The Volvo Penta 8.1s/375 hp.