Gray tank sensor

[cndondi]

I just dumped my tank and the gray tank still reads full. I assume something is coating the sensors. Refilled the tank and dumped again and it still reads full. Am I on the right track?

[vito.a]

This is a common issue. I've tried cleaning sensors and they never work properly and are very easy to damage. I recommend just replacing it.
First, I'd recommend you post the make model of your coach in your signature. Go to "User CP" in the upper left corner and select "Details" and add the info.

Do you have an Aladdin or Aladdin Jr monitor system?
They use a pressure transducer sensor screwed in the bottom side of each tank. It transmits the pressure value to the Aladdin via RJ11 telephone cable. The RJ11 wire will have a small black convoluted tubing over it. Tracing this wire (probably somewhere in the wet bay) is the key to locating the sensor.

To remove the sensor, first unclip the phone cord from the sensor.
You only need to loosen the sensor 1/4 turn with a wrench or channel locks and then it will come out by hand. Of course make sure the tank is empty first and I'd recommend rinsing it well with Dawn blue dish soap and water.

Purchase a new sensor here. They are around $50 each.
https://www.catconproducts.com/RV-sensor.html
https://www.rvnorthwest.com/

Use several layers of Teflon tape on the new sensor threads and install it just slightly beyond hand tight. Be careful not to overtighten it and crack the tank fitting.
Reinstall the RJ11 wire and then you need to calibrate it.
Follow the directions in the attachment to calibrate the sensor (both full and empty).

This may seem difficult at first, but after the first time through you can change a sensor and calibrate it in 30 min.

[Captjake1]

Clean the tank with a pressure washer, sewer jetter hose and a rotating nozzle .
There are companies that do this service also. It got ours reading correctly again.
I have since collected the parts to do it myself.

[veraken]

Take a look at this video. I had the same problem, tried it, and it worked for me.

How To Clean an RV Gray Tank & Sensors - TheRVgeeks

[CountryB]

Originally Posted by vito.a

Do you have an Aladdin or Aladdin Jr monitor system?

What's the difference?

[Captjake1]

Originally Posted by CountryB

What's the difference?

My Alladin Jr only reads engine related values. Oil pressure ,temps, turbo boost, air pressure, etc.
All of the other monitoring is through the 'conventional ' methods. Tank levels for example are the KIB lighted panel with a momentary switch.

[Rfriebert]

After several attempts at cleaning my tanks, I found that the best result (without replacing the sensors) was to put a cup of Dawn and a cup of Calgon water softener in each tank ( black and gray). Put in when they have at least 1/2 tank. Drive to you next location so that it all mixes up. Dump when you get to you next location and see what happens. My probe sensors (different than the Alladin) are clean and report properly after dumping. I also use a manual spray wand about once a year. Seemed a little cheaper than replacing it all.

[Arctickats]

Originally Posted by vito.a

This is a common issue. I've tried cleaning sensors and they never work properly and are very easy to damage. I recommend just replacing it.
First, I'd recommend you post the make model of your coach in your signature. Go to "User CP" in the upper left corner and select "Details" and add the info.

Do you have an Aladdin or Aladdin Jr monitor system?
They use a pressure transducer sensor screwed in the bottom side of each tank. It transmits the pressure value to the Aladdin via RJ11 telephone cable. The RJ11 wire will have a small black convoluted tubing over it. Tracing this wire (probably somewhere in the wet bay) is the key to locating the sensor.

To remove the sensor, first unclip the phone cord from the sensor.
You only need to loosen the sensor 1/4 turn with a wrench or channel locks and then it will come out by hand. Of course make sure the tank is empty first and I'd recommend rinsing it well with Dawn blue dish soap and water.

Purchase a new sensor here. They are around $50 each.
https://www.catconproducts.com/RV-sensor.html
https://www.rvnorthwest.com/

Use several layers of Teflon tape on the new sensor threads and install it just slightly beyond hand tight. Be careful not to overtighten it and crack the tank fitting.
Reinstall the RJ11 wire and then you need to calibrate it.
Follow the directions in the attachment to calibrate the sensor (both full and empty).

This may seem difficult at first, but after the first time through you can change a sensor and calibrate it in 30 min.

Vito.a, I ordered 3 of the sensors based on your feedback and printed out the calibration instructions. The sensors should be waiting for me at daughters in Wa where rv is. Do you think it is worth the effort to try and recalibrate the existing sensors before swapping them out? TIA Russ

[luckyd]

Not sure how long you have been RVing but check out

RV Basics .com - RV Information for RVers about RVing This is a very informative site for
all RVers, not just beginners.

[96 Wideglide]

Originally Posted by Captjake1

Clean the tank with a pressure washer, sewer jetter hose and a rotating nozzle .
There are companies that do this service also. It got ours reading correctly again.
I have since collected the parts to do it myself.

Where are you accessing the grey tank with this nozzle?

[vito.a]

Originally Posted by Arctickats

Do you think it is worth the effort to try and recalibrate the existing sensors before swapping them out? TIA Russ

Russ, the short answer is no.
I've tried removing the sensors and soaking them in blue Dawn dish soap and then cleaning them out. They have a thin membrane over the sensor and it just doesn't lend itself to cleaning. They are sensitive and never work properly again.

I do recommend every RV owner buy the LARGE bottle of blue Dawn dish soap from Costco and put a few ounces in your black and gray tanks then fill them and let them soak for a few days and then rinse them out. If you have access to the coach regularly you can do this a few times and it will get the inside of the tanks near new.
I even keep a small bottle of blue Dawn in the bathroom and every time after dumping the tanks I add some blue Dawn and a few gallons of water.

Your most difficult issue is locating the sensors. Try to follow the RJ11 telephone cord.
Best of luck!

[Captjake1]

Originally Posted by 96 Wideglide

Where are you accessing the grey tank with this nozzle?

A sewer jetter hose and nozzle through a small hole drilled in the 45 degree sewer discharge elbow. It puts out such a small amount of water, it goes right down the sewer hose.
Posted a picture 6 months ago or so. Cant find it on the phone

[Captjake1]

Originally Posted by Captjake1

A sewer jetter hose and nozzle through a small hole drilled in the 45 degree sewer discharge elbow. It puts out such a small amount of water, it goes right down the sewer hose.
Posted a picture 6 months ago or so. Cant find it on the phone

Ok...ok...all of this talk....my tank sensors got dirty!! Lol
Cleaned today and all read empty again.
Also cleaned out my sanicon pump. Eeww..
Here is my pressure washer set up.