Help! Sewer gas smell when flushing the toilet

We have a BC 3650 and after draining all the tanks and using the black power flush for 20 minutes, we dropped a chemical packet down the toilet with 5 gallons of water. Everytime we use the toilet we get a sewer smell when we flush. Is there a chance that the vent pipe could be blocked or could there be another problem we haven't thought of?
 
Thanks! We actually had to add one of those to a 5th wheel we had about 6 years ago but had totally forgotten about it. :)
We will give that a try.
 

brianharrison

Well-known member
Blank tank smells can be attributed to poor venting, and as mentioned can be reduced by adding in additional venting, such as the extreme vent.

More than not, the smells are due to waste hanging up on the walls, sensors, etc even after drain and flush. There are other threads that talk about proper conditioning, from using Calgon Water softener to reduce hard water calcification/scaling reducing waste hanging on tank walls, Dawn dish soap to help break down oils promoting waste breakdown, and proper chemical treatment. Take a search and I'm sure others will chime in....

Hope this helps.
Brian
 

CliffP

Well-known member
This is our campers first season. We use calgon and we flush every time we camp and have a sewer hook up. At sewer sites we use a clear elbow before the hose so it is easy to see when all's clear. We dump then flush and let the tank fill, dump again and let the flush run for a while with the valve open. Last flush I closed the valve and let the tank fill several times. Toilet paper etc was still coming out on the fourth dump.

We have run the flush for 20 minutes without letting the tank fill and it doesn't seem get everything. We start the flush when we start packing up and keep an eye on the tank level, seems to get the tank clean.
 

TandT

Founding Utah Chapter Leaders-Retired
We start the flush when we start packing up and keep an eye on the tank level, seems to get the tank clean.

Cliff,
Good advice with the fill and then dump, fill and then dump.
That's also what I do, using my watch to increase the time, first 60 seconds, then 90 seconds. Maybe a third time for another 90-120 seconds.
It allows water to rise pulling debris off the sides of the tank. My sensors usually work well also, with this method.

I don't walk away from the UDC with the black tank flush running however. I have just made it a point to stay there until I'm finished.
Sooner or later you are going to forget it is running and it can really mess up your day.
I have almost done this while standing there. Someone will walk up and start talking and after a minute, I remember. Oops!
Luckily I have always caught it so far, but I have talked to others who have either had water come up in the bathroom, or on the roof from the vent pipe. JMHO

Sorry, I got a little off topic from the OP.
I also use Cyclone vent covers on several of my roof vents. They really help with odors. Trace
 

porthole

Retired
Everytime we use the toilet we get a sewer smell when we flush.

could there be another problem we haven't thought of?


Do you have the vent fan on when flushing the toilet?

Fan on - doors closed - toilet valve opened - tank vapors out.......



iPhone using Tapatalk
 

CliffP

Well-known member
I don't walk away from the UDC with the black tank flush running however. I have just made it a point to stay there until I'm finished.
Sooner or later you are going to forget it is running and it can really mess up your day.
I have almost done this while standing there. Someone will walk up and start talking and after a minute, I remember. Oops!
Luckily I have always caught it so far, but I have talked to others who have either had water come up in the bathroom, or on the roof from the vent pipe. JMHO Trace

Great advice! Too easy to get talking and side tracked!
 

Ray LeTourneau

Senior Member - Past Moderator
Do you have the vent fan on when flushing the toilet?

Fan on - doors closed - toilet valve opened - tank vapors out.......



iPhone using Tapatalk

I agree with porthole, if we have one of the Fantastic fans going and flush the terlet at the same time, the vapors come right up the poop chute!:eek:
 

pegmikef

Well-known member
Under certain wind conditions, we will get the same smell in our little TT. It usually happens when we have the bathroom vent open as the vent pipe is right next to it. In our case we can just turn on the vortex fan and it will usually clear the smell out and then we close the vent. Since we have a little TT it doesn't take long for the smell to permeate the whole trailer.
 
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