New 3-24v buzzer acting up mysteriously

[sailor Martin]

Hi

I have installed a bilge pump buzzer under my main electrical control panel. It is a 24v system and the buzzer says 3-24v on the lable.

About a week afterwards it started to spontanuasly (without receiving power) make this high pitched noise. Different from the normal tone which still works fine when the buzzer is powered.

The spontaneous high pitched noise changes when movine the buzzer around, stops, starts without an obvious explanation.
I tried replacing it with another 3-24v buzzer of a different sources but the same thing started a few days later.

Any ideas?

Thank you all.

[Spot]

Hi Martin-
Do you have a picture or schematic of the buzzer, and how it is wired to your boat?
Is it supposed to come on with a float switch or when the pump is running?

[sailor Martin]

Originally Posted by Spot

Hi Martin-
Do you have a picture or schematic of the buzzer, and how it is wired to your boat?
Is it supposed to come on with a float switch or when the pump is running?

Hi
I can draw a diagram. I'm an auto sparky so no problem.

The buzzer is wired like most bilge pump buzzers. It receives power from the "manual activation" wire. This means it goes off whenever the pump is running. Either automatically or manually. I have installed many in the past. Only difference is that the system is 24v.

And again. The problem occurs when the buzzer isn't powered by the pump or anything.

Cheers

[smac999]

Well it must be getting power if it’s buzzing. But maybe only a few volts from a dirty float contact? Have you measured the buzzer voltage while it is making noise? Does it stop making noise when the bilge fuse is pulled?

[sailor Martin]

Originally Posted by smac999

Well it must be getting power if it’s buzzing. But maybe only a few volts from a dirty float contact? Have you measured the buzzer voltage while it is making noise? Does it stop making noise when the bilge fuse is pulled?

What I do know is that when it's making the noise, the voltage is stable low on the mV so not really any significant power.
I will have a look at that. But if it stops when the fuse is pulled? How do I fix this?
Perhaps get a less sensitive buzzer?