Gray tank sensors

[MVA]

I am having trouble with the gray tank sensors. The tank reads 2/3 full when empty. I have tried the GEO method (Calgon and Dawn) which has worked before but not now. Beyond ignoring the sensors, are there other cleaning methods you have used? I can pull the sensors out physically out to clean them, but I have undertailer foam.

[BobG]

It sounds like you have the internal sensors?

I went with the optional SeaLevel II sensors (external sensors) hoping I would not have a problem. My grey tank sensor has read 33% when the tank is empty and 100% long before it is full since I received the trailer. Trailer was delivered with empty tank and sensor reading 33%.

I have concluded that trailer manufacturers buy and install tank sensor systems for their price point rather than performance as long as it has a display that has a label indicating tank level.

Hopefully you will get it to work. It is not fun to have the tank flood the shower, an experience I have had multiple times.


There are tank sensors that do work.

[rubicon327]

I haven’t used it but I wonder if something specifically designed to clean tank probes would work for you...
https://www.amazon.com/Camco-41146-T...45613773&psc=1

[MVA]

Originally Posted by rubicon327

I haven’t used it but I wonder if something specifically designed to clean tank probes would work for you...
https://www.amazon.com/Camco-41146-T...45613773&psc=1

I tried a similar product first (before trying the GEO method) that is marketed by Threshold. Unfortunately it also did not solve the problem. I have had success with both the Threshold project and GEO in the past. I am concerned that BobG may be correct. An item on the fixit list.

[Brian B-P]

Originally Posted by BobG

I went with the optional SeaLevel II sensors (external sensors) hoping I would not have a problem. My grey tank sensor has read 33% when the tank is empty and 100% long before it is full since I received the trailer. Trailer was delivered with empty tank and sensor reading 33%.

I have concluded that trailer manufacturers buy and install tank sensor systems for their price point rather than performance as long as it has a display that has a label indicating tank level.
...

There are tank sensors that do work.

While I agree that RV manufacturers generally use the cheapest junk that will appear to possibly be suitable, SeeLevel is not that. I don't know how the installation was messed up in this case, but the system works.

[BobG]

Thanks, I will take it up with Escape when I get home sometime in May. They seem to think it works too and every time I have brought it up with them they say to keep using it and it will eventually learn what is empty and full. So far with with over 3 months of use this trip, nothing has changed. It still doesn't work. I am sure Escape will make it right. I think they are probably tired of me telling them it doesn't work. I did try to figure out how to calibrate it myself but got worried I might make it worse. It is a complex calibration process.

[Brian B-P]

Originally Posted by BobG

Thanks, I will take it up with Escape when I get home sometime in May. They seem to think it works too and every time I have brought it up with them they say to keep using it and it will eventually learn what is empty and full.

That sounds like nonsense to me.

In a quick reading of the manual, it appears that the senders (sensor strips) are cut to length and report level as a percentage of whatever length they are cut to. If there are two senders stacked up for tall tank the display combines the readings, but otherwise there is no calibration of the display unit. The only learning that the senders would have to do is to compensate for the tank wall thickness, and I'm not at all convinced that any action would be required.

Originally Posted by BobG

I am sure Escape will make it right. I think they are probably tired of me telling them it doesn't work. I did try to figure out how to calibrate it myself but got worried I might make it worse. It is a complex calibration process.

I don't share your confidence in ETI. ETI hasn't been installing these for very long and isn't a service business so they don't need to be and are not likely to be any good at troubleshooting. I would contact Garnet Instruments, the manufacturer. If neither ETI nor Garnet can (or will) help, an RV service business with experience with SeeLeveL might be expensive, but worthwhile.

I'm not sure how an in-person visit to Garnet might be helpful without the trailer, but they are close to my home if anyone needs me to get anything from them.

What specific model of SeeLeveL system is ETI installing? Do any tanks have a stack of two sensors?

[BobG]

Thanks Brian, I have the SeaLevel II Tank Monitor and feel confident after reading your comments that it will work if installed correctly.

I just tried to look under the the trailer to see how the sensors are installed on the Grey Tank and could not see them. When I get home next month I will crawl under there and figure it out. I have seen the sensor on the Fresh Water Tank.


Bob

[MVA]

Does anyone have a lead on the installation manual for the KIB sensors and control panel? A related comment is that I have seen on the forum comments that there are resistors in series on the probes but it is not apparent to me where they are.

thanks

[Brian B-P]

Originally Posted by MVA

Does anyone have a lead on the installation manual for the KIB sensors and control panel? A related comment is that I have seen on the forum comments that there are resistors in series on the probes but it is not apparent to me where they are.

The set of resistors are bundled together in what the RV industry calls a "resistor pack", located at the probes on the tank, and often just dangling by the wires to the probes. The red lump in this wiring harness is an example, but the pack is often a cruder package just looking like a bulky wire connection covered in shrink-wrap.

They're not just in series with the probes - the resistors are in series with each other, the probes are connected between the resistors, and water reaching the probes shorts those points in the resistor string to ground. The result is that the whole set of resistors and probes acts like one resistor which varies in resistance with water level, and that's what the panel reads.

[MVA]

Originally Posted by Brian B-P

The set of resistors are bundled together in what the RV industry calls a "resistor pack", located at the probes on the tank, and often just dangling by the wires to the probes. The red lump in this wiring harness is an example, but the pack is often a cruder package just looking like a bulky wire connection covered in shrink-wrap.

They're not just in series with the probes - the resistors are in series with each other, the probes are connected between the resistors, and water reaching the probes shorts those points in the resistor string to ground. The result is that the whole set of resistors and probes acts like one resistor which varies in resistance with water level, and that's what the panel reads.

Thanks Brian - makes sense now on what I see at the panel end of the wiring and at the tank end of the wiring. The resistor pack is probably embedded in the foam.

[ATHiker]

Originally Posted by MVA

Does anyone have a lead on the installation manual for the KIB sensors and control panel? A related comment is that I have seen on the forum comments that there are resistors in series on the probes but it is not apparent to me where they are.

thanks

Check in the forum "files' section under electrical, plumbing, .............

[MVA]

Originally Posted by ATHiker

Check in the forum "files' section under electrical, plumbing, .............

Thanks!

[MVA]

We have been troubleshooting our gray tank level indicator for the past week and it appears that it is now solved. I thought the solution may be useful to others.

Problem: We were on a 5 week trip and the gray tank level indicator on the KIB panel read either 1/3 or 2/3 when the tank was drained. I posted this problem on the forum and received help from other owners on their experiences. I also researched postings on this forum (and other forums). Suggestions from others included a faulty board in the KIB display unit. Forum comments included a weir in the gray tank exit pipe from excessive adhesive.

Try #1: We used the GEO (twice) method with no success.

Try #2: We used liquid gel dishwasher detergent (twice); ½ cup in a nearly full gray tank. The second time, we let it set for about 4 hours while we were in transit between campgrounds. The 2/3 level indicator stopped being lit and the tank read 1/3 when empty.

At this point we decided to live with this annoyance till we got home. Our trailer has underbody foam so we scraped the foam off to expose the probe terminals on the gray tank. The KIB K101 resistor pack is embedded in foam and we did not extract it.
First thing was to understand how the KIB tank level indicator works. The KIB uses a voltage divider to measure the tank levels. An internal 188k ohm resistor in the KIB panel meter is wired to the K101 resistor pack which connects to the probe terminals. The gray tank full probe terminal post is directly wired to the lead from the KIB meter in the trailer through the K101. The ⅔ level post and full post have a 68k ohm resistor across them; the ⅔ level post and ⅓ level post have a 118k ohm resistor across them in the K101. The “common” post at the bottom of the tank is wired to ground. I came across a RV Life posting (another forum) with a nice diagram: https://www.forestriverforums.com/fo...es-131266.html

• I swapped the gray and black tank wiring on the KIB panel. The black empty tank read ⅓ and the gray tank empty. Thus, the KIB panel seems to be operating correctly, not a board problem in this instance.

• I removed the wiring from the bottom gray tank probe (ground), and measured resistance between the orange lead (full probe) and ground to be open circuit. Hence wiring in the trailer from K101 resistor pack to KIB meter is good and not shorting to ground. I also measured the resistance between the full probe and ⅔ probe, and then between ⅔ probe and ⅓ probe. Resistances were nominally as expected (68k ohm and 118k ohm). Apparently the K101 resistor pack is good.

• I disconnected the bottom probe wire and ⅓ probe wires. I could not disconnect the ⅔ probe wire nor the full probe wires due to the propane line being in the way and other obstacles. I measured the resistance from the ⅓ probe terminal to the ground terminal to be ~200k ohms. That is with an empty tank. The reading should have been open circuit.

• We cut the 1.5” ABS drain pipe on the gray tank approximately midway between the gray tank transition fitting and the elbow that leads to the gray tank dump valve. No excessive adhesive was apparent as in other forum cases. Using a flashlight I could see in the tank and the p/s and rear of the tank were clean. The probes on our E19 are mounted about 4” to the left of the gray tank drain pipe on the d/s. Hence, one cannot view the probes directly from the ABS drain pipe. I ordered a 1” inspection mirror and waited two days.

• After two days, I went out and measured the resistance between the ⅓ probe terminal and ground terminal; it was now ~500k ohm and the KIB tank panel indicated an empty tank (correctly). Apparently the tank dried out and the probes measured the tank level correctly now. With my new inspection mirror and a flashlight, I could see the probe tips inside the tank. The tank side was yellowish with soap scum and the probes in contact with that material. For those that have done plumbing at home, it looked like any bathroom or kitchen drain line (no surprise). This soap scum was the culprit that was conducting between the probes and indicating a ⅓ full tank.

Almost solution: With the open ABS drain pipe, we used a 90 degree bent long bottle brush that was dipped in vinegar to clean the tank wall between the probes and the probe tips. Then we used a garden hose with a string tied to the open end of the hose, inserted the hose and used the string to bend the hose 180 degrees inside the gray tank. By moving the hose in and out of the tank, twisting the hose, and pulling on the string, we were able to wash the inside of the tank. The tank was drained and now read ⅓ (dang!).

Solution: We repeated the same approach with the bottle brush now coated in Dow bathroom cleaner (great for removing soap scum). Repeated the scrubbing with Dow cleaner several times. Flushed the tank with the hose & attached string again and now reads empty! Used the inspection mirror and flashlight; soap scum removed. Reinstalled gray tank dump valve and connected ABS pipe with Fernco connector. For good measure, we filled the gray tank full via the shower drain (all probes read correctly as tank filled) and then dumped the tank. Gray tank reads empty now.

YMMV

[HABBERDABBER]

Bravo, maestro!
You worked the problem, to a solution.
I'm not sure I'd have the moxie to do so.
But you have, and did.
Bravo, again.

Thanks for your write-up.
I may need it some day.

[gbaglo]

I just need to add an edit, "Gray tank reads empty for now."
Persevere.

[MVA]

Originally Posted by gbaglo

I just need to add an edit, "Gray tank reads empty for now."
Persevere.

Agreed. But at least the learning curve has been met. Second time around diagnosis and cleaning will take less than an hour.

[gbaglo]

And, you've saved others a lot of time and effort.

[2Travelers]

MVA, your experience and findings suggest and reinforce the need for regular, periodic cleaning of the gray tank to help prevent scum build up (and the associated increase in resistence between the probes that leads to false readings).

What cleaning method and frequency would you recommend? GEO? Liquid gel dishwasher detergent? Oh, I re-read your posts and see that you had been using the GEO method which eventually failed, would the dishwasher detergent be a more effective treatment to avoid the build up?

Any additional insight is appreciated as I'd rather not have to cut into my plumbing system to clean these probes. That was quite an effort and creative solution.

[splicer]

MVA,
What is the model number of your panel? Mine is M1860 (mfg date is 06/2021). The fresh and grey indicators work fine, but the black indicator only works to 1/3. Dustin sent me a new resistor pack but the problem is still there. I get the same resistance reading on the old and new packs.