Tank problem

[Jill]

Yesterday while running water in the bathroom sink, we heard the grey water holding tank getting full and ready to dump. However, before we could do that we heard a rather loud BOOM or POP and the 5th wheel shook. RV repair guy said that perhaps the "bladder" or "float" at the top of the air space in tank might have blown. We had water that came out when undercarriage was opened, but it very soon drained. Everything seems to be fine and we cannot see any continuing leak. I know that the shower floor is the lowest point and if the grey tank is overflowing it will show up there soon. We have filled the grey tank but no water backs up into the shower pan.
Questioning whether the "bladder" thought is correct or if we should take other action to check this out further.

[therink]

I am not sure what bladder they are referring to. As far as I know, a grey water tank is a plastic hard walled tank. The tank may flex or bulge out some as it fills. Water should back up into the shower when the tank is full. If water drained out from the belly, you likely have a leak in the tank, drain pipe, or tank fitting. If it were me, I would open the belly and investigate without delay.
Good luck.
Steve

[webslave]

If I had to "guess", and guess it would be...

I'm not aware of any "float" or "bladder" in these tanks. My thinking is that in filling the tank, it deformed from its installed shape (rectangular and flat on top and bottom). There is a vent tube stuck in the top that goes to the roof or joins the other vent stack inside the wall (my 318SAB has several vent stacks). When installed and glued up, the pipe - tank connection is rigid. Over filling the tank will cause the tank's inlet point for the pipe to move and what you probably heard was that connection "letting go". That joint is at the top of the tank and unless you over-fill the tank again, it won't leak...it just isn't water tight any longer. When it broke loose, it leaked enough water out (it isn't water tight any more) until the level was lower, hence, no great amount of water in the belly of the trailer, just enough to reduce the pressure out the vent stack attachment point.

That's my "guess" as to what happened, since the vent stack enters the top of the tank, the only way to be 100% certain would be to remove the tank or find other access to that area of the tank. If it doesn't leak now, just don't over-fill it again and it should be fine unless you start getting odors in the trailer in which case the vent pipe itself may have broken from the stress and is venting inside a trailer wall instead of up to the roof. :)

[happytrails]

Just a thought and I don't have any real knowledge here, but my tanks are mounted/strapped to the bottom of my camper in the belly. Perhaps one of those came loose/broke and it fell a little or a lot and that's what shook the camper and made the noise. I would definitely check that tank out ASAP like therink suggested...no delay.

[Royal]

Yesterday while running water in the bathroom sink, we heard the grey water holding tank getting full and ready to dump. However, before we could do that we heard a rather loud BOOM or POP and the 5th wheel shook. RV repair guy said that perhaps the "bladder" or "float" at the top of the air space in tank might have blown. We had water that came out when undercarriage was opened, but it very soon drained. Everything seems to be fine and we cannot see any continuing leak. I know that the shower floor is the lowest point and if the grey tank is overflowing it will show up there soon. We have filled the grey tank but no water backs up into the shower pan.
Questioning whether the "bladder" thought is correct or if we should take other action to check this out further.

I think you where lucky it was the grey tank. This spring we had a very similiar event with our Cougar 318SAB black tank. It was completely full and I heard a pop sound and felt something in the trailer, but could not pinpoint the problem. The next morning I was getting ready to empty the black tank and noticed the plastic material that coves the bottom of the frame looked like a pregnant whale. When I pushed on it, the slooshing feel and sound told me that it wasn't going to be a good day.
You can imagine the mess we had. What we found was the top panel of the tank (the part next the the floor bottom) had split the welded seam. The two tanks (grey & Black) are basically identical. As far as the bladder goes, there was nothing of the sort in our black tank. My suggestion even though its no fun, would be to drop the plastic belly cover and take a good look and fill the grey tank completely full and look for water. Be thankful its only dirty water, not the other kind.:(