Tank Sensor Question

[Herk7769]

Originally Posted by BlakeB

The fact is....unless you rinse the tank really well, you WILL have TP hung up on those sensors. I have the least expensive FR model ever and have not once had an issue with tank sensors. Just sayin....

Not sure where "TP on the sensors" started, but they are "button" sensors and darn near impossible for that to happen.

IMO, there is no way TP can "hang on them" to effect a reading since the TP would have to drape from the sensor all the way across the tank to the ground sensor.

It is FAR more likely that crud or slime will conduct current across the wall of the tank. It only takes a current path of less than 188K OHMS to turn on the 1/3 light and less than 68K ohms to turn on the 2/3 light. Any resistance of less than 40K OHMS will turn on the FULL light.

TurboFlushing and prevention is the best way to prevent false indications. The Gray tank is an issue since there is no flush installed and kitchen grease and food crud can foul your sensors in that tank. Only a LONG treatment with an enzyme cleaner (like RV-Digest-It) will get rid on probe problems in the gray tank. (Short of installing a TurboFlush in the gray tank as well.)

[BlakeB]

Originally Posted by herk7769

Not sure where "TP on the sensors" started, but they are "button" sensors and darn near impossible for that to happen.

IMO, there is no way TP can "hang on them" to effect a reading since the TP would have to drape from the sensor all the way across the tank to the ground sensor.

It is FAR more likely that crud or slime will conduct current across the wall of the tank. It only takes a current path of less than 188K OHMS to turn on the 1/3 light and less than 68K ohms to turn on the 2/3 light. Any resistance of less than 40K OHMS will turn on the FULL light.

TurboFlushing and prevention is the best way to prevent false indications. The Gray tank is an issue since there is no flush installed and kitchen grease and food crud can foul your sensors in that tank. Only a LONG treatment with an enzyme cleaner (like RV-Digest-It) will get rid on probe problems in the gray tank. (Short of installing a TurboFlush in the gray tank as well.)

+1.... You nailed it exactly! Left over TP can likely be a cause of some of the sludge, as well as all of the other nasty stuff, that forms in tanks. This sludge that forms (on the walls) conduct the signal of the tank being full. Only way to get around it is clean the walls very good.....TORNADO...lol.

Here's a great explanation video...

Horst Miracle Probes Demonstration - YouTube

[great white]

Dunno, almost two years with the 831RLBSS and my probes seem to work fine.

I flush the black with the stock attachment, chuck some ice in there fro time to time and try to keep some helpful bacteria in there (like septobac or something similar).

But, I'll probably end up with similar indication issues eventually....seems everybody does.

[Sailfish Bret]

Originally Posted by herk7769

Not sure where "TP on the sensors" started, but they are "button" sensors and darn near impossible for that to happen.

IMO, there is no way TP can "hang on them" to effect a reading since the TP would have to drape from the sensor all the way across the tank to the ground sensor.

It is FAR more likely that crud or slime will conduct current across the wall of the tank. It only takes a current path of less than 188K OHMS to turn on the 1/3 light and less than 68K ohms to turn on the 2/3 light. Any resistance of less than 40K OHMS will turn on the FULL light.

TurboFlushing and prevention is the best way to prevent false indications. The Gray tank is an issue since there is no flush installed and kitchen grease and food crud can foul your sensors in that tank. Only a LONG treatment with an enzyme cleaner (like RV-Digest-It) will get rid on probe problems in the gray tank. (Short of installing a TurboFlush in the gray tank as well.)

So Lou, that being said, those new sensors that you installed, seems to me would hold rolls of TP What makes them work so much better? I see another type of sensor that sticks to the outside of the tank. It comes with the monitor and all. I know it costs a couple hundred but I don't see that one getting fouled.

[timarti]

Wonky fresh water tank sensor that always read full was one of the first things fixed on the trailer after our "shakedown" trip. The dealer removed the whole underbody cover and traced the problem to a staple through the wiring causing a short.

AC did not turn off when reaching desired cooling temp. Dealer relocated the whole AC/heat controller and rewired.

The dining slide was rubbing on the floor - dealer fixed.

Not a warranty thing, but we had them add a ceiling light in the bathroom just above the medicine cabinet. Much better!

All this done in just a few days. We are very happy with our dealer, Delorme's RV, near North Bay and are so glad we went "local". They have answewed a million newbie questions. We love our Ultralite 2304s!

[beanoil]

My new V-Lite does it too. Weve been out for a total of 28 days since we got it. No TP or solids in the black tank. Flushing doesn't help.

[Herk7769]

The Horst system probe for Black has a shield over a stainless steel sensor wire and is made of non-conductive Teflon. (Middle Probe)

The probes for the gray and fresh water tanks (left probe) also have a Teflon base shaft and a curled stainless steel wire probe.

There is "almost" no way for "TP" or anything else for that matter to make a circuit from the probe to the ground probe.

I say "almost" as there is always a way when "humans" get in the picture. (Grease down the kitchen sink). Black tank still perfect.

The exterior tank sensor system is a heck of a lot more expensive and is also problematic (just for different reasons). It is a capacitance system and the MicroMonitor system is a resistive system. Capacitance systems can false from condensation and humidity.

[Sailfish Bret]

Thanks Herk, your posts and replies are always insightful and helpful.

[Herk7769]

That black probe has a "flat" on the threaded portion so that the shield is always on top of the wire when you install it.

[Blakew76]

The black tank level read "E" even though it definitly wasn't after a weekend of dry camping. When we got to the Sani dump about 1/2 hour later, it was reading 2/3. I talked to the dealer about it, they said there was possibly something covering the sensor & driving down the road removed what was covering it. They also mentioned the ice in the tank thing too.

[2Susan]

Originally Posted by f1100turbo

how does this work ?

You put the paper in waste basket. We use unscented diaper wipes - they go into the waste basket. No paper hanging on probes that way. Waste basket is lined with one of those ever present grocery store plastic bags, emptied when full (or if I am taking out other trash). No odor from what is in the wastebasket.

[Herk7769]

Originally Posted by Blakew76

The black tank level read "E" even though it definitly wasn't after a weekend of dry camping. When we got to the Sani dump about 1/2 hour later, it was reading 2/3. I talked to the dealer about it, they said there was possibly something covering the sensor & driving down the road removed what was covering it. They also mentioned the ice in the tank thing too.

Your dealer is not correct. "E" means there is no ground path AT ALL.

The only time you will see an "E," with water in the tank, is a loose or broken wire on the ground probe, or a failure in the MicroMonitor PC board.

My money is on a bad connection at the white wire (ground probe).

This will happen again and I would have them check the sensor wires for a lose connection at the tank or in the crimp hat that holds all the white sensor wires.

They won't want to because it is a PITA to drop the belly covering just to check for a loose wire. They may also charge you for the labor if they "CND" it. (Could Not Duplicate)

[Blakew76]

I thought about it after, it should read full if there's something covering the sensors, not the other way around. I'll look for a connection, if it's nothing obvious, they can look at it, (still under warranty).

[Herk7769]

There is a crimp "hat" where the white wires from both tank ground probes join with the white ground wire from the monitor. If that crimp is bad or corroded you will start having "E" indication problems.

[Blakew76]

Thanks for the info, I'll have a look