black water holding tank valve opens but won't drain

Hey All,

The reason I posted this was so someone else might search this phrase and get a match, I did not (on this site) so after looking around I tried an idea that could get me off the hook.

We went tailgating last Saturday in Eugene, OR and it was dry camping only so I shocked the water system and rinsed into the tanks and went to the water treatment plant.

Hooked up and pulled the cable T handle that runs into the belly through the corrugated plastic, it came out the usual distance but no noise, I put it back in and pulled it out a couple of times but nothing.

So frustrated, I drained the grey tanks, fore and aft and told the guys to limit their bathroom use and so I stewed about it all weekend.

Searched several threads and the net and found an idea that made some sense, I was sure the cable was not broke so here's a recipe I followed.

Take one full bottle of Dawn dish washing soap and pour the whole thing down the toilet and let it sit there for several hours.

Prepare the rig for towing, take and dump 3-5 bags of ice (I did 28#'s) right down the toilet and then hit the road, I went over speed bumps and all of the hilly side streets where I knew the trailer would bounce around a lot and in about 25 minutes I headed for the dump station.

There was a MH and a TT already there and we chatted and I told them what had happened and what I had done and by the time it was my turn they stuck around and low and behold when I opened up the valve we all heard ice cubes come a tumbling down, if I wasn't under the rig it would have been high fives all around.

I know the moral of the story is to take better care of the tank but I thought this was genius, fill with soap and then ice cubes and use the cubes as a huge scrubbing agent to slosh out the tank and scrub the sides while driving and lubricating the slide valve in the process.

I hope this might help others cause it sure helped me.

Bill

pianotuna
Nomad III
Sep 19, 2019
I suggest you watch the videos I posted. You may revise the recommendation.

allen8106 wrote:
Get a Flush King, they work great.
bpounds
Nomad
Sep 19, 2019
Durb wrote:
My strategy is to use the park's restroom for the big jobs and only deal with it once! Wish I could convince the wife.

I do use a packet of laundry detergent with five gallons of water on my way to the RV park. I then drain as soon as I get there. It is amazing how much stuff comes out even after previously using the black tank rinse. I would be leery of using a whole bottle of dish detergent. I'd be afraid of brown suds discharging out of my roof vent.

On to a more appealing thread!

Suds. That's why I use Dawn automatic dishwashing soap. Suds are a problem in automatic dishwashers too. OP wasn't specific, but did say dishwashing, not laundry. I use the sachet packets because they are easy to drop down the toilet, no spilling, no measuring. And anything that will cut grease is worth the expense IMO. Human grease is basically what holds a turd together.

As far as ice and that guy's test videos, I can't say whether ice will work, but I don't accept that his imitation feces is a proper test media.
allen8106
Explorer
Sep 19, 2019
Get a Flush King, they work great.
Cummins12V98
Explorer III
Sep 12, 2019
I have similar strategy. I don't do the toilet BOMB. It probably helps some but I never have a buildup so I don't.

"10. Close the black water tank and run the flush water in for four(4) minutes. Do not let anyone distract you at this point."

I set the timer on my phone for 10 minutes with a LOUD "BARK" when it goes off. This way I don't get distracted!

I do the 10 min flush twice. First time I close the Grey and flush it also.

I can't take credit for this setup but it's AWESOME as I don't have to do anything but turn the valves to flush the tanks.
Durb
Explorer
Sep 12, 2019
My strategy is to use the park's restroom for the big jobs and only deal with it once! Wish I could convince the wife.

I do use a packet of laundry detergent with five gallons of water on my way to the RV park. I then drain as soon as I get there. It is amazing how much stuff comes out even after previously using the black tank rinse. I would be leery of using a whole bottle of dish detergent. I'd be afraid of brown suds discharging out of my roof vent.

On to a more appealing thread!
Me_Again
Explorer III
Sep 12, 2019
Here is the routine I have developed over many snowbird winters.

1. Get a clear sight adapter and put it between the trailer and the sewer hose.
2. I leave the black tank closed for a week at a time. Grey tanks open.
3. I form a pee trap in the sewer hose with a couple boards, one 2x and a 4x4.
4. To dump and flush, I remove the pee trap boards.
5. Close the grey water tanks.
6. Open the black water tank and turn on the hose to the built in flush system.
7. Watch the sight tube until I am down to just hose water coming out.
8. Go inside and do two full bowl super flushes. "Bomb the Pile!" Note: Full bowl means filling the bowl to the bottom of the upper rim.
9. Go back outside and view discharge.
10. Close the black water tank and run the flush water in for four(4) minutes. Do not let anyone distract you at this point.
11. Open and drain and repeat 10 again.
12. Flush a bit and verify that you have nice clear water coming out of the tank. If not go back to step 8 and start again.
13. When you have nice clear discharge, put the pee trap boards back the sewer line and fill the pee trap.
14. Close the black water tank and add about a minute worth of water to the tank with the flush hose.
15. Secure the flush hose. I have a little inline valve adapter at the side of the trailer and the other end gets turned off.
16. Open the grey water tanks and go add your chemical to the tank.

I have had the burping a couple of times, however the super flushes seem to have fixed that issue.

Having piles in not good!!
valhalla360
Navigator
Sep 12, 2019
Fisher Bill wrote:
pianotuna wrote:
The ice does just about nothing--it is the water and the detergent.

When we deep sea fish for tuna we make an ice slurry in the bow compartment and when it starts to melt we can hear the ice cubes sloshing back and forth rubbing against all sides of the aluminum compartment so I have to believe that 30#'s of ice does something, YRMV

We've lived in both our boat and our RV.

If the RV moved even half going down the road as the boat in modest 3ft wave conditions, the RV would have torn itself apart.
ACZL
Explorer
Sep 12, 2019
1 flush for #1, 2 flushes for #2 with plenty of water (read almost full) each time w/ the first of the 2 w/ the "dirty" contents.

May sound silly and thought my FIL was nuts, but after we dump the tanks, we add 10 gallons to the black tank before leaving along w/ the GEO method. Tank reading isn't worth a darn, but I know tank is drained. Shoot, we went a whole week on vaykay before dumping. Granted the black tank was getting pretty darn close to full, but she drained well.
fj12ryder
Explorer III
Sep 12, 2019
How much water was in there when it wouldn't flow out? Was it full? It sounds like you only had a little water in it to begin with. Maybe just not enough to get a lot of water out. Maybe just not enough water to make much noise. We use the clear elbow so we can see if we have water moving. Sometimes it's pretty slow if the level is low.
blofgren
Explorer
Sep 12, 2019
Thank you very much for sharing your experience. I have always had this scenario in the back of my mind when pulling the black handle, but so far so good!