Black tank won't drain

[Whirly]

2012 Cyclone 3800 - I just tried emptying front black tank after about 3-4 days and nothing comes out. Wife is the only user and usually 90% is liquid, but not even liquid comes out and indicators say tank is full. I have a clear elbow so I can monitor it. Is it possible the slide drain valve is defective? Any suggestions on how to proceed?

Whirly

 

[cookie]

Wow, there are several things that could have gone wrong. When you say that your wife is the only user the first thing thing that comes to my mind is my wife......using too much paper. If this is the case you may have a plugged drain. It has happened to me. Gotta use lots of water when flushing.
You may, as you have mentioned, have a bad valve or the cable that operates that valve.
There may also be one of the cutouts from the installation blocking the drain.
So, if your clear fitting has facility to screw a garden hose on the end you can verify it your valve is working and if you have a plug.
Attach the garden hose. put your drain cover over the outlet, open the valve and turn on the water. If there is no flow then the valve is not working. If there is flow it should have dislodged any plug in the drain.
If you find that the valve is not working then you will have to drop the underbelly and have a look at the cable attachment.
Oh, and the tank monitors seldom work with any accuracy. I never even look at ours.

Peace
Dave

 

[Lynn1130]

I don't want this to sound like I am asking a really dumb question but are you pulling the correct handle? I am not familiar with the 3800 but with mine there are two handles next to each other. One is the gray water and the other is the black. The larger handle is not the black so I got a surprise the first time I pulled the one that I thought was the gray. Luckily the black had only chemical in it but I learned quickly which was which. Look under the belly to see which pipe is larger. That is the black. Pull the handle directly above that.

 

[Whirly]

That's not a dumb question at all. It took me quite a while to figure out which valves (I have 4) does what and where and I did mark them (wouldn't you think the factory would have done this?). But I am using the correct valve. I did just purchase a clear section with a back flush and and valve shut off and currently have the hose running. I have drained it twice now and some black water is coming out so I will let the water run more time and see if that works. I don't know how long to let the water run so I am experimenting. Thanks all.

Whirly

 

[Whirly]

That's not a dumb question at all. It took me quite a while to figure out which valves (I have 4) does what and where and I did mark them (wouldn't you think the factory would have done this?). But I am using the correct valve. I did just purchase a clear section with a back flush and and valve shut off and currently have the hose running. I have drained it twice now and some black water is coming out so I will let the water run more time and see if that works. I don't know how long to let the water run so I am experimenting. Thanks all.

Whirly

After several sewerpipe back flushes and factory hose flush and 5 gal of hot water down toilet, I think it finally cleared and I found out the shut off valve is not bad. At least I am getting flow out of the drain. I haven't been using any type of waste dissolver but I picked some up and will try it. Thanks for all responses.

 

[jnbhobe]

I never use any treatment just lots of water and dump when I'm full.

 

[danemayer]

If you have a slow leak at the black tank gate valve, the water will drain out slowly while you're camping and the solids will build up making it very easy for clogs to form at the tank outlet when you try to dump the tank.

After travelling, if you have more than a few drops of water spill out when you remove the cap from the sewer outlet, you may have this problem. An extra gate valve on the sewer outlet can help with this problem until you can get the gate valve cleaned out or replaced.

 

[donr827]

I never use any treatment just lots of water and dump when I'm full.

X2 Lots of water before and after having a good ----.
Don

 

[JohnDar]

I put a cup of Calgon dissolved in a couple of gallons of water after flushing and add about 5 more gallons of water via the tank flush line. Don't dump again until the toilet starts to burp. Sensors are a joke.