Jabsco Sensor-Max pump problem

[meandraft]

We have a Jabsco Sensor-Max fresh water pump. This has an in-built pressure sensor that alters the speed to maintain a constant pressure and should switch off once the pre-set pressure has been reached ie. all taps are closed. All of a sudden it now runs continuously and requires turning off via its mcb. I've checked the sytem for leaks but all seems ok. Has any body else experienced this problem. Has the pressure sensor failed?

 

[VicS]

According to the on line data sheet the causes and remedies could be:

Pump fails to turn off after all fixtures are closesd
• Empty water supply tank ................Refill
• Air trapped in pump .......................Open faucet closest to pump
• Debris in pump ..............................Remove upper housing and inspect
• Defective check valve assembly .......Replace check valve assembly
• No battery in circuit .......................Install battery
• Punctured diaphragm (pump leaks) ....Replace lower housing assembly
• Discharge line leak .........................Inspect plumbing and fixtures for leaks​

You presumably don't have an empty tank
Unlikely that you have trapped air.

Debris ( dirt ) in the pump or the valves preventing them from closing properly would be my best guess esp if you do not have a filter in the line between tank and pump.

The battery refers to operation from a power supply when using an AC to DC converter or battery charging system.

Punctured diaphragm is a possibility I suppose

You have inspected the system for leaks.

The full data sheet with details of overhauling and spares is at http://www.jabsco.com/files/31750_and_31755series_sensor_max_pumps.pdf

 

[Silver Fern]

Same problem

We have a Jabsco Sensor-Max fresh water pump. This has an in-built pressure sensor that alters the speed to maintain a constant pressure and should switch off once the pre-set pressure has been reached ie. all taps are closed. All of a sudden it now runs continuously and requires turning off via its mcb. I've checked the sytem for leaks but all seems ok. Has any body else experienced this problem. Has the pressure sensor failed?

We have had the same problem. Suddenly in the middle of the night the water pump started running. There are no air locks, no leaks, the voltage to the pump is fine. We took the upper unit apart and there is no debris. It pumps fine, but we have to turn it off at the switch board.

Did you ever find a solution?

 

[antonmanuel]

We have had the same problem. Suddenly in the middle of the night the water pump started running. There are no air locks, no leaks, the voltage to the pump is fine. We took the upper unit apart and there is no debris. It pumps fine, but we have to turn it off at the switch board.

Did you ever find a solution?

Same here. Pump only 4 months old on new boat. Have been told pump needs replacing under warranty.

 

[DipperToo]

Same here. Pump started in the middle of the night banging away at max pressure. Thought someone was banging on the hull with a hammer.

No serviceable parts and at 1 year old it was promptly exchanged by my local chandler where I bought it.

Interestingly, when the chandlers gave Jabsco the serial number they did not want it returned - is this a known issue?

 

[MoodySabre]

I tried everything when mine wouldn't stop. In the end a few hearty thumps with my fist solved it. Obviously the pressure switch had stuck probably a bit of crud after I'd run out of water. So the old maxim can work - if in doubt give it a clout.