Wiring new black tank monitor

[mrinkel]

We are on the process of replacing the sporadically working tank monitor with a Scad TM unit on our Mainship 430 sedan. I need to pull new wire because I need 3 instead of just two wires to the sensor.

Has anyone pulled wire from the engine room to the head? I'm looking for a path and there is s a lot of inaccessible space between.

Thanks,
Mark
ourpositivelatitude.com

[Codger2]

Originally Posted by mrinkel

We are on the process of replacing the sporadically working tank monitor with a Scad TM unit on our Mainship 430 sedan. I need to pull new wire because I need 3 instead of just two wires to the sensor.

I replaced a Tank Watch with the Scad TM and used the exact same wiring that the Tank Watch had. I also left the TW's probes in the tank & have had no problems with the Scad. I'm wondering why you need to run a 3 wire cable to make this conversion?

[mrinkel]

The instructions are showing 3 wires from the sensor to the display (red, blue, and black). Are you using the Tank Watch probe with the Scad? I do want to use the external tank sensor.

I did read that... "While it’s possible to connect the black wire from the sensor to a low impedance ground to avoid running a third wire, we highly recommend running the black wire from the sensor to the panel to insure a good ground for proper operation."

[STB]

I recommend running a new wire. I really do..

But, as long as the grounds at both ends are good, it isn't a problem to use a shared one on the sensor side. And, even a small difference will only introduce a small error.

One thing you can do is try it. And, if you cant calibrate it to your liking, then run the additional wire. Since you calibrate the unit for tank shape, the calibration can mitigate some of the error from resistance in the ground path.

I remember thinking about this when I installed one, but don't remember which way I went. In my case, it was an easy, straight run along an existing path, so Inthink Inadded the wire.

[mrinkel]

Originally Posted by gkesden

I recommend running a new wire. I really do..

But, as long as the grounds at both ends are good, it isn't a problem to use a shared one on the sensor side. And, even a small difference will only introduce a small error.

One thing you can do is try it. And, if you cant calibrate it to your liking, then run the additional wire. Since you calibrate the unit for tank shape, the calibration can mitigate some of the error from resistance in the ground path.

I remember thinking about this when I installed one, but don't remember which way I went. In my case, it was an easy, straight run along an existing path, so Inthink Inadded the wire.

Thanks for the info. The ground for the battery bank in which the instrument is wired is next to the waste tank so theoretically the ground will be the same if I just run the sensor ground to it. I think I will try that first as the path for running the new wire goes through a lot of areas I can't access without adding several access plates in places I'd rather not if I can avoid it.

-Mark

[Cartouche]

Originally Posted by mrinkel

We are on the process of replacing the sporadically working tank monitor with a Scad TM unit on our Mainship 430 sedan. I need to pull new wire because I need 3 instead of just two wires to the sensor.

Has anyone pulled wire from the engine room to the head? I'm looking for a path and there is s a lot of inaccessible space between.

Thanks,
Mark
ourpositivelatitude.com

I installed mine at the lower helm right next to the tank. easier to run the wires and visible when you want to see status of tank