Resolved Black tank yellow light coming on way too early

[Neal]

2017 Newmar Ventana with the 1/3, 2/3 system. On this trip my yellow light on the dometic flush control is coming on very early, level display says 2/3 when I know it's not. I have SeeLevel and right now it's around 17%. I did multiple black tank rinses recently to triage this as well as 2 uses of AquaMax, no change. I also did a 12V system cycle with a several minute off period. No change.

Good news is it not hitting red until full so this is not affecting anything other than my nerves as to why this is happening.

Any suggestions or diagnosis?

 

[Rich W.]

Mine was doing this too and my guess was that it was becuase I dropped a laundry detergent pod in thinking it would help clean the tank but instead created a lot of nasty suds that gave false readings. Well maybe that was it and maybe not, and multiple flushing/rinsings didn't seem to help, but putting about 10 gallons of water in and driving all day a couple times seems to have cured the problem.

 

[Neal]

Thanks. I'm hoping this cures itself.

 

[redbaron]

Look to see if the oem sensor strip is peeling off. This was my issue, but I was fortunate to have newmar replace it with the pressure sensor version that is flawless.

 

[Neal]

That was my thought and what I tried to see on arrival today but couldn't see it. I'll try taking the sanicon out and get a better view but I may have to pull the panel. Fortunately it's not inhibiting anything. Just an annoyance. I have an endoscope I suppose I could try.

 

[J&JD]

I have an endoscope I suppose I could try.

Or a colonoscopy. Actually I wish I had an answer. I hate problems like this that really shouldn’t happen. Glad it’s at least manageable.

 

[DKRITTER]

My yellow stays on all the time, had the coach for 3 years. We rinse regularly and well, in reality the yellow light means nothing to us.

 

[NWIP]

Look to see if the oem sensor strip is peeling off. This was my issue, but I was fortunate to have newmar replace it with the pressure sensor version that is flawless.

Flawlessly, only when it retains the programming. I have to recalibrate every time I dump. Hoping service center will fix this September.

 

[Neal]

You do not want me to be your scope'ologist! Good grief this stuff is hard. But after several tries I found the target and all appears fine. I have a feeling I have "shtuff" around the 2/3rd sensor. I think most of us drive around with empty or near empty black, I'm going to do some drives with at least 2/3rd water with some cleaning solution in it (as indicated by my SeeLevel sensor) and see if I can get the upper walls cleaned off better. This has also been the longest time the coach has sit between trips.

Used a DEPSTECH Wi-Fi endoscope which has a lighted end. Handy to have for various uses.

https://www.amazon.com/gp/product/B01MYTHWK4/?tag=rvf01-20

 

[NWIP]

You do not want me to be your scope'ologist! Good grief this stuff is hard. But after several tries I found the target and all appears fine. I have a feeling I have "shtuff" around the 2/3rd sensor. I think most of us drive around with empty or near empty black, I'm going to do some drives with at least 2/3rd water with some cleaning solution in it (as indicated by my SeeLevel sensor) and see if I can get the upper walls cleaned off better. This has also been the longest time the coach has sit between trips.

Used a DEPSTECH Wi-Fi endoscope which has a lighted end. Handy to have for various uses.

https://www.amazon.com/gp/product/B01MYTHWK4/?tag=rvf01-20

I think the sitting and drying inside of tank out is a big part of the problem. I have had way less problems with keeping tank clean since we are fulltime

 

[BGMAC]

They say put a bag of ice in with the water as you drive around. Helps with the agitation.

 

[Neal]

Arrived at a new CG yesterday, dumped, tank rinsed twice, filled with water and all the cascade I had left in the bottle (guessing 3-4 ounces) and let it sit above 2/3rd for 24 hours (near full actually) per SeeLevel. Today I hit the red light so I offloaded some to allow room to use it more and the 2/3rd light is now off. I intended to keep the level above 2/3 but dropped slightly below so at least it's a good test.

Lesson learned is when doing tank cleanings using the agent of your choice, mine is cascade or dawn, drive with it above the 2/3rd level so your cleaning agent is working against the upper part of the tank. I almost always drive empty or near empty black/grey if I can. I will now deliberately do drives for cleaning purposes from time to time as noted above.

 

[AbdRahim]

Mine was edoing that as wello. Newmar said to put Aquakem (8oz) in fill the tank and let it sit for seven days. Dump and rinse. I am part time, full time (brain teaser for you engineers), so I could not do that exactly. So, what I did was put Aquamax in (8 oz) thtank almost empty. Then used water conservatively, so I did not need to dump for seven days. Dumped and voila, screen show empty for the first time in months. This was the gray tank. Haven't yet done it with black since it goes to empty. Though it quickly goes to 1/3, it takes forever to get to 2/3. That is good enough for me. Will do the black takes, maybe in the fall.

 

[Neal]

Newmar sells AquaMax (a Thetford product) and I've seen the discussions here so I got some from Amazon and tried it twice. No luck. Not surprised, I think all tank additives by RV manufacturers are pure scam. If you want to trust a company that knows how to clean then one of the residential vendors such as Cascade, Dawn, etc. is who I trust. If cascade can handle anything in the dishwasher in my opinion it is the product to clean both black and gray tanks.

 

[AbdRahim]

The secret is seven days in the tank. But each finds his own solution. Before this I have put the entire quart bottle of Dawn i, deiven 10's of miles and dumped rinse, etc. to no avail. Glad you got it resolved.

 

[Neal]

I think the lesson learned for me as a non-fulltimer is to rethink my storage setup. I typically empty black and gray tanks for storage. It may be a better decision to have water/cleaner in the black tank to at least the 2/3rd level while in storage. Something mild such as dawn but an empty black may not be a good thing for non use.

 

[AbdRahim]

I always clean tanks, rinse and empty, for storage.

 

[Richpatty]

I found the simple step of leaving around 3-5 gallons of clean water sloshing around when you are driving keeps things pretty clean. I have never had a problem with my sensors as long as clean water is left in there. This was even true of my old Thor gasser I had for 10 years....

 

[Stuart W]

Look to see if the oem sensor strip is peeling off. This was my issue, but I was fortunate to have newmar replace it with the pressure sensor version that is flawless. This is what they look like

The 23 DS now uses pressure sensors

 

[JRS]

Another product to consider is: Holding Tank Cleaner
Must be gaining in popularity since they're currently sold out.
A well experienced full timer recommended this and said it's an amazing product. Haven't had to use it yet.
I had issues with our old system until the Mother Ship switched me to the pressure sensor.