Holding tank will not drain

[dsafian]

Hello,

I've just purchased a 1971 Overlander and am trying to drain the black water tank. I'm new to the trailer game, and am just coming up to speed. What I'm finding is that it will drain for a bit and then it stops. I then added water to flush only to find that it's diluting the rest as it will never completely drain - basically it's just the water that I'm adding that runs out.
I can still see liquid in the tank after it stops running out and the holding tank gage continues to read 4/4.

Any help?

Thanks in advance...david

[dwightdi]

These gauges are frequently wrong. There usually a little liquid remaining in a drained tank. Stick a wood stick down through the john to find out how much remains. You may need to fill the tank with a fairly good size bag of Ice cubes and drive it around a bit to break up the stuff that has sat in the bottom of the tank too long. Then drain it and watch. You might follow that up with a third of a tank of hot water and another couple of miles of sloshing followed by another dump. A little detergent in the water on that trip might help.

[ventport]

Is the trailer level front to back and side to side? If it's at an angle the tank may not fully empty when you try to drain it.

[memgrove2000]

Some times that will happen. After a weekend in ours we will fill the tank the rest of the way with hot water from the shower hose and drive it to the dump station. Where we usually get a good dump. The hot water helps the TP and solids brake down just a bit. ( I also think the volume of water helps) If this does not work we also have a stick / wand thing that we purchased from walmart. This wand is made from PVC with a cap on one end and a garden hose connecter ( with on off valve)on the other. We stick this magic wand of nasty down the toilet and turn it on... with the small holes in the end the pressure does a good job for rinsing the black tank... (We have also used the bag of ice trick but think the hot water works the same.)

When you start using your trailer remember to put some water in the tank to start. And if you are at a full hook up site... Leave the black tank closed until full or ready to leave. If you leave the black tank valve open the liquids will leave the solids behind and this may create a harder mess to get out of the tank.

Good luck and have fun.

[moosetags]

Mike is referring the the dreaded "black hills syndrome". This is caused when some unknowing RVer camps with the black tank valve in the open position. This is a super big no-no. The resulting residue is sometimes very difficult to deal with. The warm water followed by the ice trick is a good way to start. It may take doing this several times to get results.

Brian

[dsafian]

Hi Everyone - THANK YOU for the Beta

To add to the dilemma, the trailer is in a place that we cannot move again - without a great deal of trouble & expenses. (More about this on another post).

Suffice it to say - I have to get the tank clean where it sits.


- Yes it is level.
- I have tried hot water - will try more.
- Stick with hose on end sounds like a good idea.

Any more "magic" bullets - I would be grateful?!

thanks.

ds

[memgrove2000]

Ok so now we get more info... Is this trailer hooked to some type of septic or plumbing to remove waste water?... This could be mesy if just running out on the ground

[moosetags]

Are you keeping the black tank valve closed except when actually dumping? It is extremely important that you do so.

I would try more hot water soaking and leave it in for a couple of days and use some RV sewer chemical with it.

Brian

[HowieE]

Completely disregard the gauge, they do not work.

The amount of liquid you see, is that while looking down through the toilet? If so just to get an idea of how much water is in the tank use a dip stick down through the toilet. If it more than a 1/2 in you are most likely dealing with some blockage just before the valve.

I would fill the tank with hot water and let it sit until the water has cooled and dump then check the liquid level again.

If the quantity of water you can flush down into what ever system you are dumping to is not a question get a RV toilet wand and drill the hole at the end bigger and attach it to a well pressurized water supply and try and dislodge things.

As mentioned several times above. Never park with the black water valve open. This is very hard for many new campers to get a hand on but take our word on this one.

[dsafian]

Ok - here's a bit more info based on the last few posts.

I am NOT connected to any sort of sewage or septic tank. I am doing this
via bucket brigade.

.....yes, unfortunately, it's true - 5 gallons at a time

As I mentioned, it's a long story, but if the company that serviced this doesn't step up - I'll give you all the full details.

For now - I'm not planning on using the toilet - we have an outhouse - I just want to get the tank drained and keep it from stinking up the trailer - it's pretty ripe.

Yes, I understand that the valve should NOT be kept open. I am not doing this, whomever had this prior to probably has.

So - to recap - the next things to try are;
- RV wand (this sounds like a good thing to have) - is this something readily accessible or do I improvise?
- hot water
- RV chemical treatment of some type (suggestions on brand?)
or does it really matter?

Thanks again all!

[memgrove2000]

Flexible Tank Wand - Item - Camping World
and
RV Holding Tank Wands and Rinser
yes easy to get... I found ours at Walmart...
you could get a "blue boy"(portable waste water tank) to help move water. But they get heavy when full.

We use the green liquid stuff (enviro frendly some thing or other )also available at Wallymart.
All this stuff is available at camping, Rv stores, K mart, some truck stops, and campgrounds. Just look around a bit. Keep at it you will get it.

Just a thought ... is the black tank vent clear? the vent is on the top of the trailer near the rear... if it is obstructed the gasses wont breathe out the top.

[dsafian]

I have no idea what the vent for the tank is, but thanks so much for pointing that out. Will definitely check that out.

Also - thanks much for the links.

[memgrove2000]

The waste lines are vented to prevent a vacumand prevent gasses to enter the trailer. On our 31 footer there are two vents. One above the grey water line in the kitchen, and one in the rear for the black waste. They exit the top of the trailer, black plastic pipe "aprox 1.5 inch" with an cast aluminum cover. The gaskets under the covers are prone to leaking and need replacing often (2-5 years).

The links were just so you could get a visual of the "wand thingy" you could use a hose end sprayer in a pinch.

I do not know if they are all this way or just ours, but the inside of the tank is not "black" it is white in color and ours has a bump on the bottom that looks like a wad of paper, but has not changed in years so I think it is part of the tank.

You mentioned that you are getting smell inside the trailer? Does the toilet hold water? If it does then the seal in between the toilet and the black tank should be good. If not then the tank gasses could be comming up there. You can try to pull up on the foot pedle easy to help it seat the valve. Our kids sometimes dont get the valve to close all the way some times.

keep plugging away and you will get it

[dsafian]

Thanks a bunch Mike.

The toilet does not hold water, but we are not interested in using it.
Eventually, we'll remove the black water tank & toilet. For now, I just want to
get it cleared out. I will probably just fill the toilet with expandable foam to seal it, as I've been told that the toilets cannot be repaired and need to be replaced.

tx again.
david

[HowieE]

Originally Posted by dsafian

Thanks a bunch Mike.

The toilet does not hold water, but we are not interested in using it.
Eventually, we'll remove the black water tank & toilet. For now, I just want to
get it cleared out. I will probably just fill the toilet with expandable foam to seal it, as I've been told that the toilets cannot be repaired and need to be replaced.

tx again.
david

Get a second opinion on repairing the toilet. Not only can it be repaired you may be able to do it while it is in the trailer. When toilets don't hold water the knife blade is often held from closing by by paper that has been pushed into the seal. If you take a heavy coat hanger and cut it so you have a long shaft about 15 in long and bend a 1/2 right angle piece at one end and a 3 or 4 in bend at the other. Now while holding the valve open work the short bend end in and around the seal to dislodge any paper that may be holding the valve from closing.

Onc you have the seal made to the point the toilet will hold water your smell problem should be solved.

[garry]

A "Flush King" from Camping World allows you to back flush the black tank and works better than the wand but also more expensive.

I think WalMart carries a clear short section of 3" drain (in the camping section) that has a place to connect a garden house you could use this to force water into the tank backwards same principle as a Flush King without the second valve.

I say flushing backwards as you could have a clump of paper at the exit of the tank preventing any solid flow. Pushing this back into the tank might allow it to slide thru with enough water.

A less expensive and crappy solution is to shove a hose into the tank from the outside with the water on to break-up whatever might be blocking the drain inside the tank.

[dsafian]

All great suggestions - I'm on my way to the trailer tomorrow, will update you next week!!
thank you.
-david

[HowieE]

Sorry to rain on the parade but a Flush King is designed to seal a pipe and build pressure against a blockage in that pipe. The assumption is that the pipe is COMPLETELY blocked thus allowing the King to build the static pressure in the pipe equal to the city pressure. If there is any passage of water through the pipe before using the King it will never build pressure and only flow water back into the tank. The likelihood that this flow of water will dislodge anything is the same as having filled the tank as normal and then draining.

To use water pressure in the absence of a complete blockage you need to be able direct the waters kinetic pressure directly at the blockage.

Take some 1/2 in copper pipe and adapt it to a hose. Solder an elbow on the end and solder just enough 1/2 in pipe into the elbow that you can get the pipe down through the toilet. Smash the end of that short piece of pipe, at a slight angle to the bottom of the tank, to create a fan spray. Now insert the wand and start spraying.

This is the same principle as the commercially available wands but with a higher volume of water being used.

[memgrove2000]

The "flush king" or cheap walmart one.
I would not use. Looking at the plumbing in our 71 the stream of water will not go into the black tank but up the gray water drain. With no Gray water tank or valve you will just fill up the bath tub. This is just the way it is on ours, look at yours and see if the stream will go in your tank (ours will not). Our waste lines are in the rear bumper compartment and I can plainly see it would be of no help to us to use the "in line back flush device" untill we get a gray water holding tank. You may have different plumbing.

[dsafian]

There's no blockage in the line, I think the crud is at the mouth of the tank inside just keeping the majority of the solid stuck. If I put liquid in, it flows out, it just will not drain completely. I'm gonna try the hot water, & wand approach combined with some chemical treatment - we'll see how that goes.
-thanks!
david