Black tank over fill ?

CJ7Bob · 08-11-2018, 03:21 PM

I recently over filled the black water tank and didn't realize it (because gauge never works) until I noticed the under belly cover bulging and water dripping out. Is that the way they are designed to over flow or is there something wrong on top of the tank? I thought it would have backup in the toilet. I do have the cover partially removed and washed out just waiting for it to dry out.

Canonman · 08-11-2018, 03:33 PM

Actually, there should be two relief options to the black tank. The bowl and the vent.
Can't help much with the tank bulging an leaking. Only thing I would try at this point is removing koroplast under the tank and refilling it while watching for the issue to present itself. While you have things accessible up you might check into why your tank level indicators don't work. They are usually easy to troubleshoot and fix once you have the bottom opened up.

**chuckster57** · 08-11-2018, 03:37 PM

Welcome to the forum

Your black tank doesn’t have an “overflow”. I take it you were using the rinser? If you were just using the tank under normal conditions and it should have backed up to the toilet as you flushed it. If you were using the rinser, then it will fill the tank, and depending on how far the vent tube is inserted it will start pressurizing the tank. It won’t come out the toilet because there is a seal.

What exactly were you “doing” when you noticed the problem?

CJ7Bob · 08-11-2018, 04:13 PM

We were actually filling the tank through the toilet with a garden hose to add a tank & sensor cleaner before hitting the road. The tank was fuller than expected and over filled it . May have pushed the seal you mention out.

travelin texans · 08-11-2018, 08:17 PM

Quote:

Originally Posted by CJ7Bob

We were actually filling the tank through the toilet with a garden hose to add a tank & sensor cleaner before hitting the road. The tank was fuller than expected and over filled it . May have pushed the seal you mention out.

Once you've repaired your black, the next time add a healthy squirt of Dawn dish soap & a couple gallons of water, through the toilet flush pedal, travel to next spot, this works great at cleaning the tank, good luck with the sensors telling you anything except a couple of the little red lights work.

**chuckster57** · 08-11-2018, 04:27 PM

If you had a garden hose down the toilet then it would have backed up into the bowl. The bowl would be “open” with the hose holding the “flap” ajar.

I’m afraid you may have bigger issues. I would take enough of the underbelly off for a good look at the tank. Drain and refill, watching for leaks.

**JRTJH** · 08-11-2018, 05:31 PM

The black tank is a "closed container" meaning it will not leak "poo" into the underbelly under normal circumstances. As long as the system is working as designed, the only place contents should be capable of exiting the tank is the drain valve. There are two other openings, the toilet connection and the rooftop vent connection. Both of those should not vent tank contents to the outside. So, if your tank is leaking into the underbelly, you've either got a loose connection or a split tank. There are other "permanently closed" connections to the black tank, the flush port and the sensor ports, but they typically are not going to leak.

As suggested above, I'd take a long, thorough look at the tank sides and top as well as both the toilet and vent fittings, where they enter the black tank. What you're experiencing is not normal, is a health hazard and shouldn't occur.

CJ7Bob · 08-11-2018, 08:42 PM

Toilet and vent connections looked good but I think it is a split at the top corner of the tank. Previous owner may have caused it with the tank sprayer, he told me he used it all the time.

mazboy · 08-12-2018, 04:32 AM

is your tank cracked? water in the belly? is it black or gray water--the smell.

as for gagues, they never work. figure out when to dump and do it! we can go at least 2 weeks but it is just the 2 of us.

ctbruce · 08-12-2018, 04:39 AM

Just a note, my gauges work as designed. Always have, from day 1. Not all of the sensor applications are crap. Some or many is more descriptive and correct. YMMV. Mine doesn't.

**chuckster57** · 08-12-2018, 05:07 AM

Quote:

Originally Posted by ctbruce

Just a note, my gauges work as designed. Always have, from day 1. Not all of the sensor applications are crap. Some or many is more descriptive and correct. YMMV. Mine doesn't.

X2. And 99% of the RVs I have worked on.

CJ7Bob · 08-12-2018, 03:12 PM

After getting back under it again this morning I did find the crack on top of the tank. It is pretty accessible so I'll start looking for a good tank patch kit. The gauge on the black water tank has showed full since the day I brought it used, I checked connection on them while under it. I put about 5 gallons of hot water in the tank, let it set about 30 minutes ran the spray bar, still showed full. Put 20 lbs of crushed ice and a couple gallons of water and pulled trailer 150 miles, must have cleaned the sensors off it seems to be working again.

**chuckster57** · 08-12-2018, 05:52 PM

Good deal on both counts.

Just had a class C that gray wouldn’t read at all. Hot water/ Dawn ultra and a drive around the block....BAM!!

mhbell · 08-19-2018, 09:41 AM

A couple of years ago while flushing black tank on a Jayco Designer I got distracted by a Neighbor and over filled my black tank until it spread the rails and fell out the bottom breaking the pipes and ripping the koroplast. It shot poo out the top vent and all over the awning and roof. What a mess.
Mel

JWS · 08-19-2018, 01:01 PM

Quote:

Originally Posted by mhbell

A couple of years ago while flushing black tank on a Jayco Designer I got distracted by a Neighbor and over filled my black tank until it spread the rails and fell out the bottom breaking the pipes and ripping the koroplast. It shot poo out the top vent and all over the awning and roof. What a mess.
Mel

Hate to admit it but I did the same thing on our last trailer. When I opened the valve the pressure straightened out drain hose and cleaned the tank GOOD. But waste water forced its way between floor covering and floor in the bath that I did not see until floor got soft. Moral of story don't get distracted when flushing tanks. Also as a side note tank indicators have worked on all my trailers for past 15 years.

eerkescircus · 08-19-2018, 05:05 PM

I am sure all of this can be avoided if you keep the valve open when using the tank flush.
Ours says right on it leave the valve open.

KSH · 08-20-2018, 07:14 AM

Quote:

Originally Posted by mhbell

A couple of years ago while flushing black tank on a Jayco Designer I got distracted by a Neighbor and over filled my black tank until it spread the rails and fell out the bottom breaking the pipes and ripping the koroplast. It shot poo out the top vent and all over the awning and roof. What a mess.
Mel

I set an 8 minute timer on my phone. I've verified that with my hose and the pressure regulator on it, that's how long i need for a good fill, so i can flush.

rjrelander · 08-20-2018, 07:37 AM

Quote:

Originally Posted by mhbell

A couple of years ago while flushing black tank on a Jayco Designer I got distracted by a Neighbor and over filled my black tank ...

Must have one heck of a neighbor!

Skins44 · 06-05-2020, 06:55 AM

mhbell, hope you are doing well. I just did the same damn thing last night. Pulled into my wifes grandads property, it was lightning and about ready to storm, kids running around blah blah. hooked the hose to the black tank flush instead of city!!!!! Continued to set-up and realized my roof drains were dumping water, black water! to compound, i tried to flush the toilet and it literally blew up in my face. I was able to dump my blackwater this morning, however there is a little bit, not much, that accumulated in my under belly. I dont know what to do next. Anyway i could call you? - Steve in Maryland

**hankpage** · 06-05-2020, 08:28 AM

Quote:

Originally Posted by Skins44

mhbell, hope you are doing well. I just did the same damn thing last night. Pulled into my wifes grandads property, it was lightning and about ready to storm, kids running around blah blah. hooked the hose to the black tank flush instead of city!!!!! Continued to set-up and realized my roof drains were dumping water, black water! to compound, i tried to flush the toilet and it literally blew up in my face. I was able to dump my blackwater this morning, however there is a little bit, not much, that accumulated in my under belly. I dont know what to do next. Anyway i could call you? - Steve in Maryland

Steve, mhbell has not been on since February so you may have a better chance of contacting him with a PM that should generate an e-mail to him. JM2¢, Hank

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