black tank not venting?
We have a 2020 high end 5th wheel and also own a 2019 motorhome, and have owned many other coaches. This is the first time we have had this problem and I suspect a black tank venting issue but I welcome input from other members.
When the black tank just reaches about 2/3 full it really begins to stink when we flush, especially if the roof vent is open. We use chemicals and have tried many different ones. This is not a chemical issue. We have ZERO problem in our motorhome. Let me elaborate... What immediately suggested a venting issue was this...
I ALWAYS saniflush, often twice and each time I close the dump valve and carefully and watchfully let about 20 gallons in with the saniflush attachment before I open the dump valve again and let it drain again. I always empty it the last time, then add a gallon or two of water, add chemical down the toilet and then wait until it starts to stink again, always about 2/3 full on the digital gauge.
But this was the big clue. As we were leaving for the long weekend, I added my 20 gallons one last time (3rd filling), then stopped and then watched the digital gauge until it showed FULL. Then the plan was to fill it up the rest of the way using the toilet flush valve watching from the inside with the toilet valve open until it was completely full and then add some RidEx to attempt to dissolve any accumulated solids anywhere in the tank.
OOPS - HERE'S WHAT HAPPENED. My wife stepped on the toilet flusher just slightly and said it was like a geyser of water water under pressure. NOTE, I had already turned off the saniflush attachment, planning to fill the tank the rest of the way from inside. So WHY would the tank be pressurized unless the vent were not venting and filling the empty tank with the saniflush created a lot of air pressure inside which immediately rushed to escape when my wife cracked the flush valve? Again we NEVER experienced this geyser effect before because we never do this. I normally always empty the tank again from the dump valve and just put a gallon or so of fresh water inside. I only filled it up this time to add the RidEx.
So doesn't this sound like a blocked vent? And that would explain why the stinky gas builds up inside without venting? If you agree then what is my best solution? Suspecting the smell might be a blocked vent, I had asked the last guy who was on my roof to run a hose down the the roof vent tube. He said he did, but maybe he didn't let it run long enough to either clear the tube or back up and overflow onto the roof? I am thinking to try this again and watch inside the bathroom with flush valve open and see that the water is coming down thru the vent tube and filling the black tank. Make sense? Any other ideas? What else could be the problem if the hose filling from the roof vent flows freely?
HELP!
When the black tank just reaches about 2/3 full it really begins to stink when we flush, especially if the roof vent is open. We use chemicals and have tried many different ones. This is not a chemical issue. We have ZERO problem in our motorhome. Let me elaborate... What immediately suggested a venting issue was this...
I ALWAYS saniflush, often twice and each time I close the dump valve and carefully and watchfully let about 20 gallons in with the saniflush attachment before I open the dump valve again and let it drain again. I always empty it the last time, then add a gallon or two of water, add chemical down the toilet and then wait until it starts to stink again, always about 2/3 full on the digital gauge.
But this was the big clue. As we were leaving for the long weekend, I added my 20 gallons one last time (3rd filling), then stopped and then watched the digital gauge until it showed FULL. Then the plan was to fill it up the rest of the way using the toilet flush valve watching from the inside with the toilet valve open until it was completely full and then add some RidEx to attempt to dissolve any accumulated solids anywhere in the tank.
OOPS - HERE'S WHAT HAPPENED. My wife stepped on the toilet flusher just slightly and said it was like a geyser of water water under pressure. NOTE, I had already turned off the saniflush attachment, planning to fill the tank the rest of the way from inside. So WHY would the tank be pressurized unless the vent were not venting and filling the empty tank with the saniflush created a lot of air pressure inside which immediately rushed to escape when my wife cracked the flush valve? Again we NEVER experienced this geyser effect before because we never do this. I normally always empty the tank again from the dump valve and just put a gallon or so of fresh water inside. I only filled it up this time to add the RidEx.
So doesn't this sound like a blocked vent? And that would explain why the stinky gas builds up inside without venting? If you agree then what is my best solution? Suspecting the smell might be a blocked vent, I had asked the last guy who was on my roof to run a hose down the the roof vent tube. He said he did, but maybe he didn't let it run long enough to either clear the tube or back up and overflow onto the roof? I am thinking to try this again and watch inside the bathroom with flush valve open and see that the water is coming down thru the vent tube and filling the black tank. Make sense? Any other ideas? What else could be the problem if the hose filling from the roof vent flows freely?
HELP!
