Nobels 9hp bow thruster overheat warning lamps. Info sought.

[Boredrider]

Our boat is fitted with a Nobels 9HP bow thruster unit, controlled by a switch panel at the steering position. The panel has two red overheat warning lamps which have recently started to either glow, or come fully on, all the time. The thruster operates fine, and the motor does not seem to be overheating at all.

 

From a search on the forum, I see that Aquafax, who used to be the agents in the UK, no longer have any dealings with Nobels products, and I am having problems communicating with Nobels Dutch website.

 

Marine Megastore, in the UK, list various bi-metallic temperature sensors for Nobels products, some normally open, others normally closed.

 

Before I resort to taking the motor to pieces, does anyone have a complete circuit diagram for one of these units? The "wiring instructions" that I have do not show how the overheat system works, so any knowledge that is out there would be gratefully received!

[MoominPapa]

If it's the same as the one I worked on this year, then the connections on the bow-thruster are a three-section chocolate block. The outer two connections are to the switches, left and right. The centre connection is for the overheat light, and a wire goes from it to a small terminal on the back of the motor. I'm pretty sure it closes to earth in the event of an overheat.

 

If it were me, I'd start by disconnecting that wire at the bow-thruster end. If the light still comes on, then there's an intermittent short to earth somewhere in the wiring run or at the control panel end. If it no longer lights then the problem is the connection to the back of the motor, or the sensor behind it.

 

MP.

Edited September 11, 2015 by MoominPapa

[billS]

Forget them.ours flash intermittently even when the thruster is not in use. Later models dispensed with them completely.

[Boredrider]

Thank you both for your swift responses! I'll follow the first and report back. If it doesn't work, I'll do the second.....................

[Murflynn]

just don't use it except for short bursts. unless the impeller is jammed it should not overheat if only used for a couple of seconds.

 

 

reminds me of my experience on the Thames last week. Bloody great white twin screw gin palace with those big plastic balls hanging down all round, coming into the lock at a snail's pace, and no attempt to steer whatsoever, or even to use the mooring lines to guide it in - just a horrible grating sound as the bow was repeatedly pushed from one side to the other.

[NortonCanes]

Hi Boredrider Did you ever sort out the problem with the warning lights as we have the some problem  thx

[Boredrider]

Yes, indeed, I did sort the problem out, but totally failed to update this thread! The thruster eventually stopped working in one direction, so I removed the motor, and the contactors, and took it to an auto electrician in Tamworth! (Auto Electrical Services Units 14-15 Lagrange, Lichfield Rd In Est, B79 7XD)  They stripped it down and found one of the brush assemblies was shorting to the mounting plate.  All the necessary parts were freely available (from memory most of it is AC Delco stuff) and they reconditioned at very reasonable cost. (£168).  They tested the sender unit for the warning light and found it was OK.  Everything has worked fine since I refitted the motor - about twelve months ago.