Bilge Alarm

[alt]

I want to install a bilge alarm in the engine bay. I already have an auto bilge pump (with manual button, also), but there's no audible alarm. I think this is a necessary safety feature (as mentioned by surveyor today)

I'm wondering, would I tap into my current wiring, or just install a separate bilge alarm? If the latter, what to purchase? A float switch? Or is there a new fangled gadget that will sound if immersed in water (like those auto shower sump switches that are a pain in the arse and only last 6 months)

I'm just looking for a simple audible alarm, no dash dials / warning lights etc... just an audible alarm.

All advice appreciated

 

[longjohnsilver]

Simplest way is a float switch at a level where you want to be warned, connected to a buzzer. Very simple and reliable as the float switch will do virtually nothing for 99.99% of the time.

 

[alt]

Simplest way is a float switch at a level where you want to be warned, connected to a buzzer. Very simple and reliable as the float switch will do virtually nothing for 99.99% of the time.

I wonder how hard it would be to tap into the current float switch? Guessing i'd just need to tap into the live (when lifted) cable and then just to any ground for the (-)

 

[longjohnsilver]

I wonder how hard it would be to tap into the current float switch? Guessing i'd just need to tap into the live (when lifted) cable and then just to any ground for the (-)

Why not, even easier. Only potential,problem comes if and when the float switch fails, then you won't have any warning at all.

 

[Trundlebug]

Both my bilge pumps are wired to a buzzer that sounds if they activate.

Very simple to install, and buzzers are cheap and easily available - take your pick from this little lot:
http://www.maplin.co.uk/c/components/buzzers-and-loudspeakers/buzzers-and-sounders

You have 2 choices as regards installation.
1. Use the existing circuit and wire in a buzzer. Quick, easy and simple.
2. Fit a second float switch and wire the buzzer in a separate circuit. Much more work and realistically, what's the gain compared to (1)? Twice as many float switches to go wrong, plus it doesn't tell you that the pump is working - it tells you there's water in there. So you still have to check the pump is activated too.

 

[celtic_mist]

I fitted 3 of these Rule high water bilge alarms, working perfect after 5 years.

http://www.chmarine.com/cgi-bin/sh0...=Rule-High-Water-Alarm-12v-33ALA.html#SID=554

 

[salar]

Here's one I made earlier, even watches while you are away. http://www.boat-angling.co.uk/Hints_and_Tips/bilgemonitor.htm
Yes I know the relay is charged, but I am on shore power and the drain is negligable.

 

[alt]

Both my bilge pumps are wired to a buzzer that sounds if they activate.

Very simple to install, and buzzers are cheap and easily available - take your pick from this little lot:
http://www.maplin.co.uk/c/components/buzzers-and-loudspeakers/buzzers-and-sounders

You have 2 choices as regards installation.
1. Use the existing circuit and wire in a buzzer. Quick, easy and simple.
2. Fit a second float switch and wire the buzzer in a separate circuit. Much more work and realistically, what's the gain compared to (1)? Twice as many float switches to go wrong, plus it doesn't tell you that the pump is working - it tells you there's water in there. So you still have to check the pump is activated too.

I am going to purchase one of these and go with option 1, mainly because there are spade connectors already in place, so all I have to do is mount buzzer and piggy in... happy days!

 

[longjohnsilver]

I am going to purchase one of these and go with option 1, mainly because there are spade connectors already in place, so all I have to do is mount buzzer and piggy in... happy days!

Surely by doing that you have the problem that if the float switch fails (which they do) then your bilge could be filling up and you'd be unaware of it.

 

[alt]

Surely by doing that you have the problem that if the float switch fails (which they do) then your bilge could be filling up and you'd be unaware of it.

Well it's still one step better than the current set-up. I can get more creative next winter when i'm bored, for now I just want to get a bilge alarm working.

 

[Trundlebug]

Surely by doing that you have the problem that if the float switch fails (which they do) then your bilge could be filling up and you'd be unaware of it.

But if you fit a second float switch to operate the buzzer, either:-
1) that one could fail and although the bilge pump is working you wouldn't know about it, which is the whole point of fitting it
2) The one on the pump fails but you hear the alarm on the buzzer (if you're there) so you're able to address it - happy days
3) Both fail, and you're really in it.

With twice as many switches there are twice as many to fail.
Overall it's no better or worse than just having one switch to operate both pump and buzzer

 

[longjohnsilver]

But if you fit a second float switch to operate the buzzer, either:-
1) that one could fail and although the bilge pump is working you wouldn't know about it, which is the whole point of fitting it
2) The one on the pump fails but you hear the alarm on the buzzer (if you're there) so you're able to address it - happy days
3) Both fail, and you're really in it.

With twice as many switches there are twice as many to fail.
Overall it's no better or worse than just having one switch to operate both pump and buzzer

Disagree with that. Float switches almost always fail with use. Belt and braces you'd have your buzzer/alarm connected to both.

 

[P4Paul]

I wired in a siren to both the bilge pump and to a high water float switch with a relay and a couple of diodes.
That way you get an alarm if the bilge pump starts working or more importantly, an alarm if it doesn't.