Black Tank Sensor shows 2/3 full when its empty

[ChevyTech77]

Leave your dump valves closed but cap off, when not in use. It will dry off the sensors.

[dhunt]

Lucky I have another camping trip coming up in two weeks on a site with full hookups which will give me a chance to experiment. We have been staying a several sites recently with dump stations and when there is a line 4 deep behind me I tend to feel like I am holding up the line and probably don't clean it as well as it needs to be cleaned out. I will report back on what works

[5picker]

Originally Posted by ChevyTech77

Leave your dump valves closed but cap off, when not in use. It will dry off the sensors.

Could you explain this?
If the valves are closed (with the cap off) how could it dry the sensors?

[Herk7769]

Originally Posted by Chuckinca

how do you clean the flush wand?

I assume this is for me:

The flush wand is a spray down unit for cleaning the bowl.

[Herk7769]

Originally Posted by ChevyTech77

Leave your dump valves closed but cap off, when not in use. It will dry off the sensors.

Leaving the dump valves closed will ensure the sensors remain in a damp environment inside the tank; which is good. If the crude on the sensor dries out, it will be darn near impossible to remove with just flushing. You will most likely need to replace them in that case.

These sensors have crusted crud on them and I had to replace them. I replaced them over 5 years ago with Horst Probes. BEST money ever spent on the camper.

[ChevyTech77]

Originally Posted by 5picker

Could you explain this?
If the valves are closed (with the cap off) how could it dry the sensors?

Wish I could explain why it works so well but I can't. I know it does though as ever sense I have been doing it that way, in between uses, my sensors read perfect now.

[Herk7769]

FYI, the white on the Horst probe is Teflon and nothing sticks to it.

If you do this upgrade, use the "Black Tank" probes (with the wire shield) on the Gray tanks too; at least for the shower collection tank. Our daughter has long silky hair stayed with us a week once and the Gray tank probes needed to be changed out as the spring coil trapped her broken hairs.

[Schvarak]

Originally Posted by ben31

There is no fail-safe method. Everything has trade-offs.

I second the black tank wand cleaner. That is the only thing, which will completely clean your tank and the sensors. Just be aware, using TP or not, as soon as you use it once, you will have residue on the walls, which will need to be cleaned off with the wand. Thus, you are back to the false readings.

We gave up after about 6 trips. We now just know when we need to empty it, based on our common usage. We know we can go about 7 days without emptying the black tank, so really no longer pay attention to the black tank sensors.

You can pay 300-400 to replace the sensors, you can run the wand every time you dump, etc. Or you can just learn what your tank is telling you and move on. There are other discussions elsewhere and depending on what they are trying to sell, will depend on the conclusions they make. My advise...just live with it.

The last two paragraphs say it all! Great advice! I use a Camco dual flush valve every seven days (my typical dump frequency) i flush the tank 5-6 times. It doesn't clean the sensors completely but good enough for govt work. Not worth the money to change sensors. Or dragging a hose and wand around the living area. Just don't worry about it!

[5picker]

Originally Posted by ChevyTech77

Wish I could explain why it works so well but I can't. I know it does though as ever sense I have been doing it that way, in between uses, my sensors read perfect now.

Thanks.

I simply can't get my head around anything here that would dry out the sensors.

The sensors are inside the tank.
The valve blade seals off the tank when closed.
Leaving the cap off would allow the drain pipe to 'dry out' but nothing else beyond that.

I would think you'd have more of a chance 'drying' the sensors through normal roof stack evaporation than by leaving the cap off and the valves closed.

Glad though it works for you.

[ben31]

Cleaning the wand.

Pull it out, wipe it dry with some paper towels, and then you can just tie a plastic shopping bag around it. I store it with my other tank accessories. Although, like I said, I still have it, but haven't used it in almost a year.

[Fred and Christine]

Originally Posted by ben31

There is no fail-safe method. Everything has trade-offs.

I second the black tank wand cleaner. That is the only thing, which will completely clean your tank and the sensors. Just be aware, using TP or not, as soon as you use it once, you will have residue on the walls, which will need to be cleaned off with the wand. Thus, you are back to the false readings.

We gave up after about 6 trips. We now just know when we need to empty it, based on our common usage. We know we can go about 7 days without emptying the black tank, so really no longer pay attention to the black tank sensors.

You can pay 300-400 to replace the sensors, you can run the wand every time you dump, etc. Or you can just learn what your tank is telling you and move on. There are other discussions elsewhere and depending on what they are trying to sell, will depend on the conclusions they make. My advise...just live with it.

X2. I gave up trying to clean the sensors a long time a go.

[Herk7769]

The sensors are 35 bucks and you need 2 black sets (one for the black tank and one for the Shower holding tank) - 70 bucks total.

You won't need to change the Galley (unless it is the shower too) or Fresh Tanks as they usually work very well.

Takes all of 30 minutes per tank to change once you drop the belly Coreplast (hardest part of the job, so pick a non-windy day to do it).

Even with a light breeze (made maneuvering that big piece of plastic a chore), it only took me 3 hours start to finish to do both tanks.