Black tank will not empty

[Jakenbear]

My 2019 Bighorn 3760EL black tank shows 2/3 full on the monitor panel, however, with the black vale open it still registers 2/3 full. I did make the mistake of leaving the black tank valve open while hooked up to sewer line. (The manual says Never do this) So I suspect either my tank line is clogged or the panel is in error. When I started out on this trip the black tank registered 1/3 full, even though I had drained and cleaned it after our last trip about 2 months ago. I have since closed the valve and put 2 packages of deodorant/ bacteria eating stuff down the toilet. Any ideas or suggestions would be appreciated.

Thanks,

 

[danemayer]

Hi Jakenbear,

First, the gauges are notoriously unreliable. A little paper or crud on the sensor may cause a 2/3 reading on a completely empty tank.

Second, when you leave the black tank valve open, as you use the commode, the water immediately flows into the sewer. The solids built up into a pile that can be difficult to break down. After a while, it becomes difficult to get any solids to come out.

You might try a hose with spray nozzle blasting water down through the commode to break down the poo pile. After that, try back flushing multiple times.

Before starting to backflush, run water into a bucket to see what the fill rate is from the hose. If for example your fill rate is 4 gallons per minute, and you have a 40 gallon black tank, you could safely run the backflush for about 8 minutes (32 gallons) without overfilling the tank.

I'd suggest a clear adapter on the end of the sewer outlet, like this one. It twists onto the sewer outlet and your sewer hose twists onto the other side of the gate valve. Close the gate valve on the clear adapter and run water into the backflush fitting. Use the timer on your watch to make sure you don't overfill the black tank. Then drain. Watch what comes out. Repeat, repeat, repeat.

 

[JohnDar]

Just to add to Dan’s recommendations, invest in a water meter to accurately measure what you put into the tank. A battery powered digital one that goes on the hose will run about $20.


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[Piperflyer]

Hi Jakenbear,

Before starting to backflush, run water into a bucket to see what the fill rate is from the hose. If for example your fill rate is 4 gallons per minute, and you have a 40 gallon black tank, you could safely run the backflush for about 8 minutes (32 gallons) without overfilling the tank.


If you do a back-flush, just make sure you don't get DISTRACTED and forget you're filling your black water tank. I know 3 people that did this, got doing something else while the tank was filling and overfilled their tank; till the weight of the tank was to much for the brackets of the tank to hold. The tank fell out of it holding spot on the frame and they had a **** of a time repairing it.
Also never go by what the lights on you tank monitor panel is trying to tell you. They never work properly and will always give you false readings.

 

[david-steph2018]

On our old Laredo we had the black tank plug up. Back flushing did not work so we had to get a mobile repair person come out. It took him a little bit to get it freed up but he did. And it took me about $150.00 too.
Why it plugged could never figure out why, could had been not using enough water or the valve leaked by and drained the liquid out leaving the solid behind.

The sensors will give you false readings after they get dirty. You must leave the drain valve closed until it is time to dump. I usually dump around 2/3 or 3/4 full. You will learn a way to tell when it is time to dump by the sounds of when you flush. I also leave the gray tank closed so I can have that water to flush after dumping the black tank to clean the drain hose.

If you every figure out a method to keep the sensors working correctly and cleaned, you will make a fortune.

 

[Gaffer]

Before you leave on your nest trip, put in 5-10 gallons of water, one bottle of Dawn dish soap and 1/2 bottle of Calgon liquid water softener. Dump when you arrive. Then use the Geo method regularly. https://wheelingit.us/2012/03/21/rv-tank-sensors-the-geo-method/

 

[jbs80122]

My 2019 Bighorn 3760EL black tank shows 2/3 full on the monitor panel, however, with the black vale open it still registers 2/3 full. I did make the mistake of leaving the black tank valve open while hooked up to sewer line. (The manual says Never do this) So I suspect either my tank line is clogged or the panel is in error. When I started out on this trip the black tank registered 1/3 full, even though I had drained and cleaned it after our last trip about 2 months ago. I have since closed the valve and put 2 packages of deodorant/ bacteria eating stuff down the toilet. Any ideas or suggestions would be appreciated.

Thanks,

Yep. I made that mistake. Once. It's funny how clever I thought I was right up until the time to clean the tanks came. One trick I learned is that before you leave on your next trip, immediately before you hit the road, dump a 20 lb bag of ice cubes down the toilet with a little water. The cubes will slosh around and scour the tank pretty well before melting. And definitely get the clear section, and always use the black tank flush.
John

 

[esscobra]

are you full time or occasional use? in years helping others I have found the thetford level gauge cleaner usually works and heard good things aboput the commando cleaner paks- all requires leaving tank full for a while to let it soak and hopefully clean whatever is making false reading

 

[Oregon_Camper]

Yep. I made that mistake. Once. It's funny how clever I thought I was right up until the time to clean the tanks came. One trick I learned is that before you leave on your next trip, immediately before you hit the road, dump a 20 lb bag of ice cubes down the toilet with a little water. The cubes will slosh around and scour the tank pretty well before melting. And definitely get the clear section, and always use the black tank flush.
John

I did that ice trick for a while, then I watched a few YouTube videos (like the one below) that convinced me this was no longer worth the effort. Best trick...empty tank...flush...fill and let soak.

https://youtu.be/iH6acEmqvcw

 

[Big-B]

I read somewhere that you are supposed to run a couple of gallons of water into the black water tank after you empty it to give things a splash zone. I've always done that and never had a problem when we are parked and living in our trailer for three months plus. I also do this before we hit the road and I think it sloshes around while moving down the road and loosens things up in the tank.

 

[danemayer]

You might find our owner-written Water Systems Guide to be helpful.

 

[Jakenbear]

are you full time or occasional use? in years helping others I have found the thetford level gauge cleaner usually works and heard good things aboput the commando cleaner paks- all requires leaving tank full for a while to let it soak and hopefully clean whatever is making false reading

Thanks to all the members for their suggestions. We are fairly new about RVing (3 years) and have not had this problem before. I have tried several suggestions, to no avail. Right now we are back in the storage area waiting for a warmer day, so I can try back flushing again. The first back flush only clear water came out. The last time there was a lot of brown water, however, after, the monitor still reads 1/2 full. Someone suggested using Dawn to help break up the mass. Think I'll try this next. Thanks again.

 

[WillyBill]

Call a septic tank pumping company. Quick n easy. Let a pro do it.

WB

 

[danemayer]

If you're only trying to fix the monitor, you're wasting your time.

 

[Big-B]

Thanks to all the members for their suggestions. We are fairly new about RVing (3 years) and have not had this problem before. I have tried several suggestions, to no avail. Right now we are back in the storage area waiting for a warmer day, so I can try back flushing again. The first back flush only clear water came out. The last time there was a lot of brown water, however, after, the monitor still reads 1/2 full. Someone suggested using Dawn to help break up the mass. Think I'll try this next. Thanks again.

I don't get hung up on what the gauge says. Those gauges are pretty much worthless in a black water tank in my opinion. Having water in the tank sloshing around while you go down the road will likely break things up a lot better than flushing it will.

 

[esscobra]

I would get the commando tank cleaner or the thetford level gauge cleaner- fill tank and let sit then try the flush es- warmer is better for these to work- I luckily have dump and water at storage area- so I drain, flush till clean and then usually put good amount of water into tank, then ill dump on way out - but always leave some in black tank so it does not go dry- if it will be short before next trip thin I will add water and a blue packet and be ready to head out

 

[Drainmaster]

Thanks to all the members for their suggestions. We are fairly new about RVing (3 years) and have not had this problem before. I have tried several suggestions, to no avail. Right now we are back in the storage area waiting for a warmer day, so I can try back flushing again. The first back flush only clear water came out. The last time there was a lot of brown water, however, after, the monitor still reads 1/2 full. Someone suggested using Dawn to help break up the mass. Think I'll try this next. Thanks again.

Good morning, Doug at Drain Master here. If you are still having issues getting your Black Tank unplugged I would be happy to work with you to resolve the current issue as well as provide you with some information that will eliminate this type of issue in the future. We specialize in RV Waste Management, have for the past 18 plus years and resolving fellow RVers waste issues is one of the many things we do in our effort to make dumping holding tanks; As simple and uneventful as putting fuel in a vehicle. I can be reached easily 831 801 4827 Cell.

 

[Jakenbear]

Good morning, Doug at Drain Master here. If you are still having issues getting your Black Tank unplugged I would be happy to work with you to resolve the current issue as well as provide you with some information that will eliminate this type of issue in the future. We specialize in RV Waste Management, have for the past 18 plus years and resolving fellow RVers waste issues is one of the many things we do in our effort to make dumping holding tanks; As simple and uneventful as putting fuel in a vehicle. I can be reached easily 831 801 4827 Cell.

Thanks Doug, But fortunately for me I have resolved the clogged tank. Commando tank cleaner appears to have worked well.. Thanks again.

 

[Drainmaster]

Thanks Doug, But fortunately for me I have resolved the clogged tank. Commando tank cleaner appears to have worked well.. Thanks again.

Very good, glad you were able to resolve the issue without having to get professional help. Here is an article I wrote some time ago that you may find useful .

With appreciation,

 

[Jeremy1990]

Black tank line leaking

Hi guys I’ve been fighting mice all week finally it appears I’ve gotten them to leave the trailer
And I went to use my tank flush and the water line is leaking I had to use a borescope to find but I don’t know how to reach it
I have a 2017 gateway 3650bh it line I’m needing to fix is just above the water heater but to right to reach
and goes up the wall


so does anyone know the path to the line? How can I get to it?