In a bit of a predicament (Black Water tank full and frozen)

I didn't read anywhere in your posts that you are making sure the black tank is at least half full before trying to dump it. You need to have enough liquid in the tank to create a swirling motion to flush all the solids out. If you were dumping weekly, it may be that you were only getting the liquid out but leaving a lot of solids behind accumulating in the bottom of the tank until it finally reached critical mass so to speak. May not have anything to do with freezing temperatures especially if it only got down to 30 degrees overnight.

If it's just a build up of solids from neglect, get the proper holding tank "chemical" and use it exclusively. The blue stuff just is a deodorant. Get an enzyme treatment. It will take a few fill/drain cycles to get fully working as the blue stuff inhibits it from working properly so you have to flush all remnants of that out of the tank to have full effect. Once you do though, it works great. It digests waste and toilet paper and makes everything come out when you drain. It also prevents odors.

EXAMPLE OF WHAT I MEAN

Once you get the problem fixed, you need to do the RIGHT thing when camping in freezing weather-------Pour a couple of gallons of RV antifreeze in the tanks after each dump to prevent freezing. Doug

If it's 30F average, I doubt it's frozen solid. More likely solids clog.

Are you going purely off the tank sensors? They are notoriously bad and often will continue to show full or partially full even with an empty tank.

It appears the compartment is enclosed so you would just need to put one of the personal 250W heaters in there and plug it in. It will warm everything up pretty quickly. Since it's only 30 degrees outside it should not take long to thaw things out. Be sure it's well sealed and give it as much time as possible.
You may also be able to install a cap like this http://www.campingworld.com/termination-cap-with-hose-connector on your output connection and blow water backward up the discharge to free up and blockage. You need a hose with female connectors on both ends but it does work.

You can rent a kerosene heater from most national hardware stores. They are sometimes called bullet heaters and are used extensively by contractors for outdoor situations. Needs to be plugged in to operate but takes very litlle electricity. The blast from the heater will flood the area of the frozen tank and should reduce or eliminate the issue. Good Luck.
Buy the way you can own a homeowner version of the heater for around $150.00. Home depot, True value, Lowes to name a few.

I'm sorry for the lack of information. It's about 30 f here in northern Washington. Got ocean on one side, and the Puget Sound on the other. It's a really pretty area.

I've been living in this 28ft 1990 Fleetwood Southwind for closing in on two months now. Been trying to repair it as we didn't know what we were doing when we bought it. So I've discovered a lot of problems, and am trying to make it livable until I can afford a nicer one, or move.

The black water tank is about 30 gallons I believe? It's a Chevy chassis if that helps at all. Doesn't appear to be underbelly enclosed.

Can you recommend what heating pads would work?

I actually had taken some pictures of the holding tanks to share with a friend, hoping we could figure out some means of resolving the issue of it not draining.







There's a Rhino reverse flush 40 degree elbow on it right now, but due to the fact I can't get the tubing through the normal hole I'd feed it through, the door is left open, and the angle makes it hard for all the water to drain out. It's not enough to burst the pipes, or tubing I don't think.

Alright so basically a few days ago I went to drain it, and a little came out then it stopped. So I tried dumping numerous pots of near boiling water down the toilet. Water was on still so it cooled it a bit when it went down.

I tried adding more TankTechRX I think it's called, and nothing. Tried the stuff that's suppose to unclog it by TankTechRX, still nothing. Tried to use vinegar, let it sit overnight.. Nadda. Sensors were showing full before, now I'm seeing 3/4ths so I'm assuming it cleaned the sensors off or.. one stopped working.. It's also not burping now so something must have gone down.

When I used the reverse flush, I got some stuff loose, but it didn't seem to really do much else? I let it run for a bit trying to get in there and knock whatever was clogged up, loose. Nadda. The water was clear after I dislodged some stuff, and the only thing draining was what was being blasted up the pipe.

Anyway, it froze a couple nights ago, and I waited until mid day to try draining it again since I didn't want to mess with it if it were completely frozen. Nothing came out. Gray water was full again, so I drained that with no trouble.

When I tried moving the black water valve earlier, I heard what I thought was the valve shifting open and breaking some thin ice that had built up (this was at 4 in the afternoon.. Wasn't going to get much warmer than that). Nothing came out still. It was trickling before when I first started a few days ago, now it's nothing at all.

The previous owners didn't take care of it. We didn't know what we were doing when we bought it, so I've been searching the world wide web for information on how to do repairs, and try to keep this place livable until I can afford to get a better RV. It's in pretty bad shape, but it's a roof over my head until something better comes along.

Would adding RV antifreeze even work in a tank that's full? I can do it with the gray water for sure. That's a very good idea and I'll do that as soon as I get a chance to make a store run.

I'm adding a skirt to it as soon as I get all the materials. R-Tech 1 inch Styrofoam is the last thing I need. Just a matter of getting a truck since the nearest home depot/lowes is a half hour from here.

Hahaha don't need another poop facial. Learned that lesson when the dump hose flipped and splashed me.

Thanks for the advice. Space heater is out of the question for now, but hopefully we'll get the shore power fixed and won't be running on minimal.. everything.

You didn't give us much background to go on. You are from Home. I don't know what the weather extremes are there. What kind of trailer do you have? Is the underbelly enclosed? How big is your black tank? That type of information is helpful.
My advice - find some place warm to park it. You can buy 12 volt tank heaters that stick to the bottom of the tanks. I had them on my first trailer. rarely used them, but they worked when I did. They aren't going to help with the exposed plumbing, though. Maybe adding some antifreeze to the mix will help a little. Skirting the bottom edge of the trailer and putting a space heater in there may also help.
One thing guaranteed to open up the dump pipe, is to get your face right up to it and look in it. The longer you look, the greater the chances of getting a poop facial will be and the problem will be solved. Good luck. Let us know how it comes out (pun intended).