Jabsco Bilge Pump won't switch off

[picardy]

I have a Jabsco Bilge pump with (until recently) an air switch which suddenly would not turn the pump off. I recently replaced this with a new Eco Switch (basically the same). After a few weeks the same problem has arisen again.

The pump is isolated via a standard breaker with a red push button for manual override. The bilge will not now switch off unless the breaker is turned off which prevents it cutting in automatically.

Does anyone have any ideas where I can start to trace the fault. Behind the panel the bilge wires are routed into a small 1" square black box that clicks when the breaker is switched.

I assume the Eco Switch is the issue but turning the allen key in the front to adjust sensitivity does not seem to make any difference.

 

[stevebrassett]

Personally I would start with a multimeter on both contacts of the swtich to make sure it was making/breaking contact, then take it from there. If the switch is not breaking contact, it is faulty. If it is you have a short somewhere. Remove the switch before testing to make sure you test one thing at a time. In fact, the small block sounds like a relay, so that's the next thing I would test.

 

[Graham_Wright]

Does anyone have any ideas where I can start to trace the fault. Behind the panel the bilge wires are routed into a small 1" square black box that clicks when the breaker is switched.

The click will almost certainly be a relay. Many level sensors are low current devices, e.g. reed switches. They cannot handle the inductive load presented by an electric motor.

Mt guess is the relay is sticking on. Give it a tap and see if the pump stops.
You can find replacemen relays on eBay, e.g. started solenoid relay.