Toilet burps water when flushing

[PaulHi]

My Pinnacle upper toilet burps water when flushing. Any ideas on how to resolve this?

[Cavie]

Originally Posted by PaulHi

My Pinnacle upper toilet burps water when flushing. Any ideas on how to resolve this?

both my trailers do that when the black tank is full.

[norty1]

Agree, on my rig it's more dependable than the gauges. Time to think about dumping black tank.

[CAG]

Yep. That is the sign that it is time to dump the black tank.



If by chance you just emptied it and it is still doing that you likely have a poop pyramid below the toilet and are going to need to do some extra work to flush it.

[deepsea5]

Originally Posted by CAG

Yep. That is the sign that it is time to dump the black tank.



If by chance you just emptied it and it is still doing that you likely have a poop pyramid below the toilet and are going to need to do some extra work to flush it.

^^^I concur^^^

Another issue could be the tank vent is obstructed.

[Camper_bob]

Originally Posted by deepsea5

^^^I concur^^^

Another issue could be the tank vent is obstructed.

+1

For me, the "burp" is how I know when to empty the tank. But usually I'm filling it with fresh for a rinse/dump at that time anyway.

[Jagiven]

Originally Posted by CAG

Yep. That is the sign that it is time to dump the black tank.



If by chance you just emptied it and it is still doing that you likely have a poop pyramid below the toilet and are going to need to do some extra work to flush it.

X+1

[Jeffur]

My bet is vent is obstructed

[craigav]

Originally Posted by Jeffur

My bet is vent is obstructed

I bet Jeff is correct. BTW, if you have a sink nearby, there is likely what is known as an "Air admittance valve" under that cabinet that lets air in when water goes down the drain and keeps the air from coming out of the drain line. In other words it is a one way valve allowing air into the drain line (when working properly) but keeps any air from coming back out. Many times they get stuck in the open position which leads to a stinky situation, however they could get stuck in a closed position as well which would\could cause an issue as described. You should be able to replace it easily enough and in fact I think most hardware stores have them in stock (not just rv stores). I don't know for sure, however it may even be possible to unstick one, maybe with taking it out and using a water hose. ~CA

[deepsea5]

Originally Posted by deepsea5

^^^I concur^^^

Another issue could be the tank vent is obstructed.

Originally Posted by Jeffur

My bet is vent is obstructed

A blocked vent can cause the tank to build pressure.

The portable toilet on our boat is unvented. The DW learned the hard way that you always crack the slide valve (with the lid closed) to relieve any tank pressure and reclose it before using the toilet. She forgot to do this only once. The results of whipping the slide open with a bowl full of urine and a pressurized tank really made her pissed!

[deepsea5]

Originally Posted by craigav

I bet Jeff is correct. BTW, if you have a sink nearby, there is likely what is known as an "Air admittance valve" under that cabinet that lets air in when water goes down the drain and keeps the air from coming out of the drain line. In other words it is a one way valve allowing air into the drain line (when working properly) but keeps any air from coming back out. Many times they get stuck in the open position which leads to a stinky situation, however they could get stuck in a closed position as well which would\could cause an issue as described. You should be able to replace it easily enough and in fact I think most hardware stores have them in stock (not just rv stores). I don't know for sure, however it may even be possible to unstick one, maybe with taking it out and using a water hose. ~CA

The black tank "should" only have toilet waste going to it. The vent pipe between the tank and roof could be obstructed.

[craigav]

Originally Posted by deepsea5

The black tank "should" only have toilet waste going to it. The vent pipe between the tank and roof could be obstructed.

Yes, I agree, I had a brain fart... lol ~CA

[norty1]

When the tank reaches the level of the vent pipe in the tank, it cannot vent anymore so ---hence the BURP! It usually extends down into the tank a little.

BURP!

[Scott_Trailer_Newbe]

It is full!

[Camper_bob]

Originally Posted by deepsea5

The black tank "should" only have toilet waste going to it. The vent pipe between the tank and roof could be obstructed.

Originally Posted by craigav

Yes, I agree, I had a brain fart... lol ~CA

Some units are plumbed with the bathroom sink going into the black tank. This happens (IIRC) if the head is comparatively far away from the other water fixtures in the unit. Cheaper/faster to plumb the sink drain into the black tank (which is usually VERY close to the toilet) than to a gray tank on the other side/end of the unit.

Now, whether that sink would be equipped with an air admittance valve, I couldn't tell you...

No matter what, there are only 2 causes for a burping toilet (and really it all comes down to 1 cause). 1) an obstructed tank vent or 2) a full black tank.

If it happens all the time (and you KNOW the tank is empty, and you don't have the dreaded "poo pyramid of death"), then the tank vent is likely obstructed. If it only happens after you've been using the toilet for a while, then your tank is likely full; time to empty.

The full black tank blocks ventilation, so it "burps" up the chute and through the toilet valve (because the air has no other path).

[Curly2001]

Yep, it's time to dump the tank or look for a clog on the way down. Mine clogged once and I had to use the power flush to get things moving. Use lots of water.
Curly

[campersam9]

I had a wasp nest in the vent on my roof. Had to wait till dark and spray water on them. Wasp spray is not good on the roof.
I put a wire down then used my blower. Make sure the black water valve us opened.

[Andrewf]

A friend of mine had a similar problem. He found that the vent cap for the black tank up on the roof had slipped down into the pvc pipe far enough to block it off from venting. He corrected the problem with a new cap that would not slip down. He told me his toilet has never flushed better after the fix.

I'd check your vent cap.
Andy

[Tcdoughboy34]

The problem is your air vent going up to the roof is plugged!

[cartpix]

I had a clog between the toilet & the tank, which caused mine to burp.