Re: Bilge Pump, auto or manual ???
I think there is a bit of confusion here.<br /><br />There are two types of bilge pumps, automatic ones and non automatic ones. Automatic ones do not use a float switch and some of them can be operated manually and some can not. Most bilge pumps are not automatic and have to be connected to an outside switch, be it an automatic float switch, or a manual switch, but they must be connected to one or the other or both. This is far and away the most common type of pump.<br /><br />So its likely that you do have a non-automatic pump, in fact if you have a switch up on your dash that allows you to manually turn the pump on (if its working) then you most assuredly do not have an automatic pump, or if you do its wired inproperly.<br /><br />So, with all that said here is the deal on bilge pumps and how to wire the most common sort and the least common sort.<br /><br />The first things first. Fully automatic pumps have their own built in water senseing system. Every now and then (usually at about 1 second intervals I believe)a pulse of power is sent to a sensor and if there is wate there the pump kicks on. So with these pumps you have to supply a constant power supply, normally comming from the main battery switch, and there is no manual over ride switch up on the dash.<br /><br />The much more common setup is to have a bilge pump that simply runs whenever power is supplied to it. These kinds, which are what you will find in the vast majority of boats, are usually connected to an external float switch. Power is supplied to the float switch constantly and if there is water present the float lifts, making the switch connect, and the power is passed on to the bilge pump, which then pumps the water out of the boat. These pumps can also be powered by a manual switch of course. In that case power is supplied to a switch on the dash and the output side of the switch is connected to the pump. So if you reach down and hit the switch the pump should kick on. Very simple. Of course most pumps are connected to both a float switch and a manual switch up at the dash. That give you the best of both worlds.<br /><br />OK, how about reliability? Pumps last forever, float switches are horribly unreliable, manual switches fail, but not too often. The biggest problem with bilge pumps is usually the wireing itself. So, when a pump fails to work first check the wires for power; second, suspect the float switch; and last, look at the bilge pump itself.<br /><br />So, how to wire one? That part tends to confuse folks a bit, but its not so bad. The first rule is never to connect any device directly to your battery. I do not care who tells you that it is ever acceptable to connect devices directly to a battery, DO NOT DO IT! Batterys are to be connected to battery switches, engine grounds, or buss bars - nothing else. First look at the automatic side. Connect a suitable large wire to power the bilge pump to the input lug on your battery switch. This will be the same lug to which the positive cable from one of your batterys is connected. Within a foot of the switch put an inline fuse of appropriate amperage. Now, run that wire to the float switch and connect it to either of the two gray wires from the switch. Next, make a connection between the other wire on the float switch and the brown wire from the bilge pump (this is where you will also connect the manual wire I'll describe below). Finally, make a connection between the black wire from the bilge pump and your negative side buss bar. There, the automatic side is wired.<br /><br />If you want to have a manual over ride you will simple place a switch at the dash and power it from your fuse block or circuit breaker panel. Then you will connect a wire between it and the wire from the bilge pump's brown and the one of the float switch's gray wires that you had connected to it. This is the connection I mentined above when I was on the automatic hookup.<br /><br />For all of this use marine grade wire, buy the stuff made by Anchor and you won't have to worry about it. I like to solder all of my joints and then coat them with a sealer (usually 5200) and then I put a section of shrink fit over them. This treatment makes them last about as long as they possibly can, but they will still rot out on you after a few years (salt water) and have to be replaced from time to time.<br /><br />So, there, did that make any sense? If no I'll try to explain it better.<br /><br />Thom
