Vent pipe broken off black water holding tank?

PamIvy · 09-15-2014, 03:13 PM

Hello!

I have a 2010 189FBR. I am having water pour out the top of my black water holding tank. I don't know why this is happening, the tank is not even near full when it happens.

Yesterday, I made sure the tank was empty by opening the black water tank valve and draining out the deodorizer and water in it, and also the tank monitor said it was empty. Then I slowly slowly poured in one gallon of water at a time down the toilet. The first time I tried, I managed to get in 10 gallons of water before it started running off the top of the tank. I crawled under the trailer and stuck my hand up over the tank and it was like a pool of water sitting on top of the tank. So I emptied the tank again and also took the leaf blower and blew the water off the top of the tank. Then I tried again.

This time I used a funnel with a long hose on it so the water I was pouring in to the tank went directly to the bottom of the tank beneath the toilet. I managed to get 15 gallons in. I crawled back under to check the top of the tank and sure enough, there was a pool of water there...though not as much because I stopped before it started running off the top of the tank. I drained the tank, blew the water off the top of it the best I could and called it a day.

Today, I took my video camera and laying flat on my back under the trailer, while my son pointed a flashlight, I videotaped the situation through the 2-3 inch gap between the bottom of the trailer and the tank.

This is what I saw. The toilet pipe seems ok, but the other pipe...is it the vent pipe? Does it look broken to you? If so...how do I repair this! Ack.

http://youtu.be/ZZLRj-S8ekQ

Here is another video of the pipe I believe is affected. Pretty good capture, I think, since I was videotaping this laying flat on my back with the camera completely over the edge of the tank! I had no idea what I was actually filming!

http://youtu.be/djb1O9i9iNQ

I look at this and can't imagine this is anything good.

LG · 09-15-2014, 05:57 PM

Hi, I'm interested in your problem because it's similar to mine. And, I agree, anything associated with "black water tank" is probably not good. I own a 2002 T160. It's a small 13 ft. trailer and is my first one ever. It has no tank level indicators or fancy stuff. It has a black tank that takes 10 gallons (I think). I bought the trailer used about a year ago and we've never used the toilet in it. We're mostly weekenders and don't mind using the showers at the parks so we just use the toilet/shower closet as a linen closet and I pack all the drinks (beer/wine/soda/water) in an ice chest on the shower floor in there. The guy I bought it from told me he had it about a year and had never used the toilet either. Whether he was being truthful is moot now but at least when I flushed it with a few gallons of water it came back crystal clear the first time, so at least I know the tank was probably clean when he sold it to me. For other various reasons I have come to suspect that this particular trailer had a major rebuild done at some point but that's another topic...

Anyway, earlier this summer I wanted to determine just how big the tank was so I backfilled it slowly using a backflush attachment and watched the water rise by holding the toilet drain open (with the water pump turned off, of course). I expected the water to rise up into the toilet. Instead, as it got close I heard the trickle of water running under the trailer. I shut off the backfill and looked underneath the trailer and saw that the water was running out from ON TOP of the floorboard through various holes wherever it could find a way. GASP! Glad it was clean! Not wanting to get into it right then, I concluded that the toilet was not seated properly onto whatever it is that extends up from the tank up through the floorboards and is supposed to connect to the toilet. Wifey assured me that she wouldn't need it for our planned summer trips this year so I left it as is and I'm just now thinking of looking into it again as I think about getting ready to winterize.

Your situation sounds a bit different than mine because the leakage you see is coming at the top of the tank whereas mine is above the floorboard. I looked at the videos you linked and, truthfully, I wasn't able to make out much, but just from the little I know about how they work there are two connections on top, one to the toilet and one to the vent pipe, one or both of which could have come loose on you. But you probably already knew that. The trick for you will probably be getting the tank dropped down and then resealing everything and putting it back in which I suspect will not be an easy job while lying on your back. That is, assuming the tank is intact.

I've probably not been much help but thought I'd post and commiserate and describe the problem I'm having, too, with the hope that some of the more experienced folks on here might have some helpful insight about how to troubleshoot or work on these things in general. All I've done so far is watched a video or two on line about installing black and grey tanks. I haven't even gone as far as to take off the access panel that allows access under the toilet and shower and have a look in there. I guess I'm a little afraid of what I might find...

Let me know here whatever/whenever you find out more.

Kevin & Kate · 09-17-2014, 07:29 AM

LG, is it possible that the situation you described is normal? I'm wondering if there is an overflow pipe/valve at the top of the black water tank that is intended to let the contents flow out to the outside rather than back up into the toilet. Neither situation is ideal, of course, but if I had my choice, I'd rather the "stuff" overflow out onto the ground than into my trailer. In absence of such a pipe or valve, where else could it go but back up into the toilet? (Which would probably leak onto the bathroom floor.) I don't know the answer to the question, just wondering (and hoping someone who does know will read this and answer).

LG · 09-17-2014, 11:56 AM

I don't want to hijack PamIvy's original post here. He was looking for some guidance about why he's seeing leakage at the top of his tank under the trailer.

I watched a video a while back where the guy was showing how to backflush a black tank and he said that if the black tank was back filled too far it would back up through the vent pipe and spew out on the roof. That would mean that there should, normally, be no leakage at any of the connections to the tank nor up through the toilet flush valve - that is - assuming the flush valve is closed. In my test I figured if I held the toilet flush open as I back filled the tank, then, as the black tank filled with water, the water should rise up into the toilet bowl before it backed up into the vent pipe. but instead, it did neither. The leakage came between the toilet and the floorboard of the trailer which suggests to me that the toilet seal might be the problem.

There's a molded plastic insert that forms the floor of the restroom. The shower drain comes up through it and the toilet also sits upon a raised portion of it. There's a space underneath it, above the floorboard of the trailer which can be accessed through a screw-on panel from inside the trailer. In my test, the water actually leaked into the access area beneath that plastic insert and then ran out and dripped onto the ground through various pathways. I haven't removed the access panel and looked at the toilet seal yet but I do think that's where my particular problem lies.