Plumbing venting?

[rkscott]

A neighbour in a travel trailer and I have noticed a similar situation. With the black tank drain closed when u step on the pedal to flush the toilet we are experiencing a kind of burp or back pressure....doesn't affect the operation. Removed roof vent cover and all appears good. It appears to be a back pressure issue so the water here is extremely salty here where we are camped. Your thoughts please and thank you. Keith

[wolfe10]

If the pipe from the roof vent has fallen down in the tank to below the fluid level in the tank, it will NOT vent.


So, if you blow air down the vent and hear bubbles.........

[DavidEM]

This is unfortunately a fairly common problem. Either the factory installed the vent line sticking too far into the tank, or as implied above, maybe it slipped down. The only real solution other than living with less usable tank volume, is to drop the tank and install the vent so it is just barely poking into the tank. Not an easy or pleasant job.

David

[Old-Biscuit]

liquid in=air out

Vent is obstructed........air burps out via toilet

Either as suggested by 'wolfe10'----vent line slipped down and is blocked by level in tank
OR vent line is obstructed with birds nest etc

Slipped down....go up on roof/remove vent cap and check whether top of vent line is level with rough line are down below it by few inches
Slipped down....grab with piers and pull up level---secure with screw thru pipe into roof sheeting

Obstructed.....go up on roof/remove vent cap
Shove garden hose with nozzle down pipe/turn water on and blast away


My toilet 'burps' when tank is FULL and time to dump it

[sbleiweiss]

They also burp when a dreaded poop pyramid is partly formed. Solution is to clear partial pyramid.

[Lowflyer1]

Originally Posted by rkscott

A neighbour in a travel trailer and I have noticed a similar situation. With the black tank drain closed when u step on the pedal to flush the toilet we are experiencing a kind of burp or back pressure....doesn't affect the operation. Removed roof vent cover and all appears good. It appears to be a back pressure issue so the water here is extremely salty here where we are camped. Your thoughts please and thank you. Keith

With this comment I sense that you normally keep the black tank drain open?
This will create a poop pyramid as mentioned previously.
The black tank should be closed until ready dump & flush the tank.

[153stars]

Be careful using a garden hose down pipe. Owners have found vent pipes not glued at joints letting smells escape into coach. Just running down pipe for a bit would be pretty safe to test . I would be real careful trying to unplug an obstruction with any amount of pressure.