Electrical Gremlin

[markc]

I've been trying to solve / understand an electrical gremlin with my water pump. It's a Gianneschi EcoJet which although old, works well. However, when I turn on the breaker I get a very high reading, or EEE (out of range) on the Charger Control readout. The high reading is not stable and jumps about ( I'm not entirely sure what this display is for, as it works when the battery charger is off and no shore power.) The water pump and tank gauge are the only things on this breaker. In trying to resolve I have checked and remade all the connections in the junction box by the pump, likewise with the pressure switch (I actually replaced it, but it's mechanical so can't see it would be the problem). I have checked the brushes and they look OK, plus I have blown out any carbon build-up around the brushes. I have also disconnected the level gauge. Nothing has made the slightest difference.

As I'm not brilliant with electrics, do any of you wise folk have any suggestions?

 

[Seastoke]

Does it do it every time , there could be a tight spot on the pump which makes it stall for a split second ,have you got a clip o amp meter you could use by the pump.

 

[markc]

It does it when the motor is idle or running, random readings in both states.

 

[Portofino]

The winding s are end of life ? Something to do with there insulation breaks down ….gradually.
Can you get a new motor ? Maybe speak to the manufacturer, they ( in my experience) tend to have great technical support . Based on dealing other Italian boaty gizmos .

 

[vas]

Mark, idle motor as in OFF, right? is it 24VDC or 230VAC?
When you say high reading, you mean amps?
maybe use an amp clamp to see consumption?

if you've redone everything locally by the pump and isolated all bits, I'd get two fresh wires STRAIGHT from battery (or charger, or el.panel) to motor (after disconnecting existing ones) and see if it works okay (may need amp clamp again though...)
before going through that, I'd check the el. panel side for any loose cable on the breaker (in or out) and redo the GND just in case.
other than that explore the drastic expensive solution that Porto mentions above, but would be odd if it actually runs fine!

V.

 

[markc]

Mark, idle motor as in OFF, right? is it 24VDC or 230VAC?
When you say high reading, you mean amps?
maybe use an amp clamp to see consumption?

if you've redone everything locally by the pump and isolated all bits, I'd get two fresh wires STRAIGHT from battery (or charger, or el.panel) to motor (after disconnecting existing ones) and see if it works okay (may need amp clamp again though...)
before going through that, I'd check the el. panel side for any loose cable on the breaker (in or out) and redo the GND just in case.
other than that explore the drastic expensive solution that Porto mentions above, but would be odd if it actually runs fine!

V.

Thank Vas. By idle I mean breaker on but motor not running. The abnormal reading is not on the ammeter but on the Charge Control display. Maybe internal capacitors leaking and triggering phantom voltage was one suggestion I received, which could potentially be resolved by installing a resistor to bleed this off??

 

[vas]

what Charge Control Display do you have Mark, just curious. Is it an aftermarket thing or a builders main el. panel display thing?
Does the ammeter on the el.panel (dunno if it's needle or digital) stay stable?
the only 24VDC motor I've taken apart (and fairly recently) was one from an Osculatti (sp?) bilge pump that would only fire up if you "helped" it with your hand to start spinning.
There are 2 small pea size capacitors by the commutator brush assembly. I recon they are gone and will replace.
Now, I'm saying that as if the motor gets no power I struggle to see how these smallish caps could mess with the whole system in an open circuit (as it should be when breaker up and pressure switch not on hence motor not running).
If you've disconnected the lever sender/gauge from the breaker (hope both!) then I'd be tempted to blame the pressure switch tbh, just think about it, it's the only piece that is "live" when motor is off, motor is OC!

since these pumps are in the 1k euro region (iirc) I'd be tempted to take the motor apart, see what's going on, find the caps and replace, but I v. much doubt it's them tbh.
we need a proper el. person to help here

 

[markc]

Hi Vas, the Charger Control is a builder display. It seems to sense the amps provided by the charger, as when I turn on other items it rises from 0.1 to maybe 3 amps. It's a digital Pantec display with red display. I'm not totally sure on its usefulness because it still displays a reading when the charger is off and with shore power disconnected! Maybe of course I misunderstand its purpose.

The pressure switch was my first thought, so I replaced it a couple of weeks ago. Only issue was it was first set to 30-50 psi and the pump was working too hard to maintain the pressure and after 3 showers, it tripped. Since lowered the thresholds.

I did put a resistor on the pump yesterday after the pressure switch and that did nothing. I'm beginning to wonder if it's not actually the pump, but something I don't know about on the same circuit

 

[vas]

odd, what if you disconnect the pressure switch and the gauge sender/display, leave the pump motor only in the circuit and turn on the pump for a bit (with a tap open for good measure!)? will it mess about the readings?
Else as you say it's something else in that circuit which you've not identified yet that is messing up.

goodluck - or maybe even ignore

 

[markc]

Ok, problem.solved. I found an old unused waste level gauge on the same circuit and that must have been introducing the interference in the circuit. Unplugged and problem went away.