Tank Sensors

NuthatchBC · 07-07-2017, 01:50 PM

I was under our 19 today doing some paint touch-ups on the frame and noticed that the tank sensors appear to be machine screws with a wire attached going into some sort of plastic receptacle. Since we've had very erratic readings from our tank monitor, I'm wondering if I could take those screws out and, if required, clean them off with detergent and replace them in their holders, hopefully solving the readout issues.

Anyone ever tried this? If so, were the results favorable?

Doug

padlin · 07-07-2017, 02:32 PM

I don't think it'd be worth the effort for a few days of correct readings. Replacing them with Horst wouldn't be a bad idea on the tank you can get to.

**rbryan4** · 07-07-2017, 02:40 PM

Quote:

Originally Posted by padlin

I don't think it'd be worth the effort for a few days of correct readings. Replacing them with Horst wouldn't be a bad idea on the tank you can get to.

I was going to say the same thing. If you're going to the trouble of removing the probes, replace them with ones that don't give false readings - or just leave it alone and don't worry about the monitor.

wetzk · 07-07-2017, 03:59 PM

Make sure you are looking at the grey water tank not the fresh water one.
There are no horst problems for the fresh water tank.

Also, twice now I have had the grey water tank start reading 1/3 to 2/3 full when empty. The first time I was not sure what was going on and tried cleaning it out. Then it would go back to normal then all of a sudden act up again. I noticed it was when it was damp or raining that it acted up. So I looked underneath and had dust all over the back of the tank around the probes. I hosed it off and problem solved. Same thing 2nd time. If you travel on dusty roads and your grey water tank levels act up try rinsing the probes off. Apparently the horst probes can read outside the tank when they are dirty. Maybe the regular probes can too.

Quote:

Originally Posted by rbryan4

I was going to say the same thing. If you're going to the trouble of removing the probes, replace them with ones that don't give false readings - or just leave it alone and don't worry about the monitor.

Brian B-P · 07-07-2017, 04:15 PM

Quote:

Originally Posted by wetzk

Apparently the horst probes can read outside the tank when they are dirty. Maybe the regular probes can too.

The level monitor just measures conductivity. If wet stuff on the outside of the tank provides a conductive path between the (exposed) terminals of the probes on the outside of the tank, that should provide the same effect as wastewater providing a conductive path between the probes on the inside of the tank... regardless of the probe design.

Perhaps a solution could be to cover the exposed terminals with an insulating caulk or sealant.

**rbryan4** · 07-07-2017, 04:45 PM

Quote:

Originally Posted by wetzk

Apparently the horst probes can read outside the tank when they are dirty. Maybe the regular probes can too.

They don't read outside the tank. The Horst Probes just have a different design on the internal portion of the probe. They use a thick copper wire, surrounded by teflon or "hooded" with teflon depending on whether they are the gray tank or black tank probes. This design means the internal contents of the tank don't cling to the probe, conduct electricity, and produce a false reading.

wetzk · 07-07-2017, 04:51 PM

I have a squirt bottle of water I use to clean the brown stuff from the toilet bowl. It works to clean the probes too. You would think the fresh water would get dirty and act up but so far that one has been fine. I just need to stay off the dusty gravel roads.

Quote:

Originally Posted by Brian B-P

The level monitor just measures conductivity. If wet stuff on the outside of the tank provides a conductive path between the (exposed) terminals of the probes on the outside of the tank, that should provide the same effect as wastewater providing a conductive path between the probes on the inside of the tank... regardless of the probe design.

Perhaps a solution could be to cover the exposed terminals with an insulating caulk or sealant.

wetzk · 07-07-2017, 04:54 PM

They can read external, otherwise how can you explain how my cleaning the damp dust off them corrected the misread.
It's probably a rare problem, and Florida dust may be more conductive when wet.

Quote:

Originally Posted by rbryan4

They don't read outside the tank. They just have a different design on the internal portion of the probe. They use a thick copper wire, surrounded by teflon or "hooded" with teflon depending on whether they are the gray tank or black tank probes. This design means the internal contents of the tank don't cling to the probe, conduct electricity, and produce a false reading.

**rbryan4** · 07-07-2017, 05:07 PM

Quote:

Originally Posted by wetzk

They can read external, otherwise how can you explain how my cleaning the damp dust off them corrected the misread.
It's probably a rare problem, and Florida dust may be more conductive when wet.

If they're corroded externally, coated externally with something wet, or there's a short in the wiring, I suppose they could send a false reading. I was just pointing out the differences between the stock probes and the Horst. Assuming the false readings come from internal issues, Horst Probes fix that. Assuming it's from external corrosion, Horst Probes fix that too.

NuthatchBC · 07-07-2017, 05:21 PM

I'm not as concerned about the accuracy of the readings as much as having something in the trailer that doesn't work. It just plain pisses me off

We've gotten used to the goofy readings and have other means of assessing the condition of the tanks. I guess I'll just let it go..........

Doug

wetzk · 07-07-2017, 05:34 PM

Quote:

Originally Posted by NuthatchBC

I'm not as concerned about the accuracy of the readings as much as having something in the trailer that doesn't work. It just plain pisses me off

We've gotten used to the goofy readings and have other means of assessing the condition of the tanks. I guess I'll just let it go..........

Doug

Have you tried cleaning the tanks? My previous trailers did not have horst probes and usually when I bought them had useless sensors. I found using the GEO method seemed to work fairly well at cleaning them out and usually restored correct operation.
If you have the stock sensors you might try breaking loose and tightening the screws that hold the sensor wire on.

Fox hunt · 07-08-2017, 01:03 AM

Trailers made after 2018 will have Horst probes. I'm having them installed on my trailer but it's not a big issue for me if the sensors are not accurate.

escape artist · 07-08-2017, 07:19 AM

Hi: All... You think you have probe problems... let me tell you about mine!!! After 11 years my pacemaker battery is running low. Some days the conductivity along the probes is too low to function causing useless readings!!! Our "Gubbermint" health plan wants to see me on my knees before they'll pay for a replacement. Now that's a probe problem!!! If I bend over to inspect the tanks by eye I might end up doing a face plant. Alf
escape artist N.S. of Lake Erie

padlin · 07-08-2017, 10:00 AM

Quote:

Originally Posted by escape artist

Hi: All... You think you have probe problems... let me tell you about mine!!! After 11 years my pacemaker battery is running low. Some days the conductivity along the probes is too low to function causing useless readings!!! Our "Gubbermint" health plan wants to see me on my knees before they'll pay for a replacement. Now that's a probe problem!!! If I bend over to inspect the tanks by eye I might end up doing a face plant. Alf
escape artist N.S. of Lake Erie

Horst's would be cheaper.

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