Missing Roof Vent ? What...?

[Walter Pigeon]

This might apply to other models and brands as well...
We have a venting issue with the grey tank and when the tank gets around 2/3 full you can hear it gurgle up thru the shower drain, occasionally we will get some suds/liquid as well. I assumed a blocked vent on the roof... so up I go with tools in hand, remove the cap to the grey tank vent and BEHOLD there isn't a vent pipe, just the fiberglass roof panel !! the vent device is mounted to the fiberglass roof and doesn't connect to anything... I removed the black tank vent cap and found a black vent line. I radioed my DW to run some water in the sink... nothing. So I asked her to run some water in the toilet and heard that just fine...

So, is the grey tank NOT vented? Vented into the wall cavity? or what ?

Is this kind of chicanery common, I have no idea where to start to find the missing vent from the waste tank !!!

Suggestions ??

[14apex]

...just to be sure I'm understanding -- the cap was actually "installed" (glued or screwed or riveted?) on the roof? No vent pipe extending through the roof (no hole in the roof for a vent pipe)? Incredible! It would seem that some extremely dishonest person intentionally "hid" the very incomplete manufacturing(?). Were it not for the "fake cap" I'd wonder if the vent had been "combined" with the black(?). I can think of no other way to locate (hopefully!?) the vent pipe than to crawl under & find it exiting the tank...then trace (hopefully?) by removing panels, drawers, etc. to find where it's routed & terminates...if, indeed, a pipe was even installed? Yep, this seems to be one of those "I thought I'd seen everything". Keep us posted, please.

[kenandterry]

Originally Posted by Walter Pigeon

This might apply to other models and brands as well...
We have a venting issue with the grey tank and when the tank gets around 2/3 full you can hear it gurgle up thru the shower drain, occasionally we will get some suds/liquid as well. I assumed a blocked vent on the roof... so up I go with tools in hand, remove the cap to the grey tank vent and BEHOLD there isn't a vent pipe, just the fiberglass roof panel !! the vent device is mounted to the fiberglass roof and doesn't connect to anything... I removed the black tank vent cap and found a black vent line. I radioed my DW to run some water in the sink... nothing. So I asked her to run some water in the toilet and heard that just fine...

So, is the grey tank NOT vented? Vented into the wall cavity? or what ?

Is this kind of chicanery common, I have no idea where to start to find the missing vent from the waste tank !!!

Suggestions ??

Walter......

Are you talking about the vent cap located on the roof above the co-pilot seat near the right front? I’ll be waiting for you to reply.

[Walter Pigeon]

We have a 2011 Georgetown 337DS- The head is located amidships, aft of the entrance door on the Starboard side.... both vents are directly above the bathroom within 18" of each other... The vent from the Black tank functions fine and has a piece of 1 1/2" ABS coming thru the FRP (fiberglass) roofing material terminating in an identical vent cap. The Grey tank is NOT connected to the black vent pipe... I will take a picture of the fake vent cap in the daylight tomorrow morning. The more I consider what someone intentionally did the more it infuriates me !

[bubbles]

Don't have an answer for you but these are supposed to be shots of a 2011 337DS

[kenandterry]

Originally Posted by Walter Pigeon

We have a 2011 Georgetown 337DS- The head is located amidships, aft of the entrance door on the Starboard side.... both vents are directly above the bathroom within 18" of each other... The vent from the Black tank functions fine and has a piece of 1 1/2" ABS coming thru the FRP (fiberglass) roofing material terminating in an identical vent cap. The Grey tank is NOT connected to the black vent pipe... I will take a picture of the fake vent cap in the daylight tomorrow morning. The more I consider what someone intentionally did the more it infuriates me !

Ok....without a picture of this vent, I’ll just tell you what IS on the roof of my 2010 Georgetown 330TS.
What appears to be an EXTRA stack vent, is located on the roof over top of the co-pilot seat. I pulled the round plastic cap off, and inside I found coax and a 18 gauge wire. Investigations later concluded that this was the pre-wire by Forest River for satellite TV. Instead of investing a different style of cap, they just used the same cap you find for black tanks.
Have you found anything inside your cap you’re mentioning?

[SlowrideHD]

Originally Posted by Walter Pigeon

The more I consider what someone intentionally did the more it infuriates me !

I think it's just the cover for a junction for a sat dish connection? Possibly.

[Walter Pigeon]

Originally Posted by kenandterry

Ok....without a picture of this vent, I’ll just tell you what IS on the roof of my 2010 Georgetown 330TS.
What appears to be an EXTRA stack vent, is located on the roof over top of the co-pilot seat. I pulled the round plastic cap off, and inside I found coax and a 18 gauge wire. Investigations later concluded that this was the pre-wire by Forest River for satellite TV. Instead of investing a different style of cap, they just used the same cap you find for black tanks.
Have you found anything inside your cap you’re mentioning?

Just the FRP roofing and some dirt...

[AquaMan]

I'm guessing both tanks are plumbed into the same vent tube. The reason you hear gurgling through the shower could be because the vent may be sticking down into the gray tank too far and forcing air through the shower drain. I'm with others, in that the other pseudo vent is most likely for satellite/solar wiring.

[Walter Pigeon]

Originally Posted by bubbles

Don't have an answer for you but these are supposed to be shots of a 2011 337DS

Interesting... one vent... If this is your rig do you encounter the same back-up in the shower ? I had the DW run water while I listened at the vent pipe (Black) and heard nothing... if the used a common out let you would think you would hear running water. And why would someone put a phony second vent head up there ?

[Bill m]

My unit a 2012 x 360 has internal auto vents on the grey tanks. If you search for grey tank vent valves you may find a similar units.

[Walter Pigeon]

Originally Posted by AquaMan

I'm guessing both tanks are plumbed into the same vent tube. The reason you hear gurgling through the shower could be because the vent may be sticking down into the gray tank too far and forcing air through the shower drain. I'm with others, in that the other pseudo vent is most likely for satellite/solar wiring.

I am starting to think the tank vents are together... when the grey tank is near full, if the vent pipe is "in solution" I wouldn't hear water running as the vent would be essentially muted. I also discovered individual auto (Schluder) vents under each of the other sinks. I can buy the though of the extra vent was intended for a solar installation but there isn't anything there to indicated it's purpose.

[Walter Pigeon]

I want to send a shout out to everyone who offered a reason for the venting issue... This site has been invaluable in our RV lifestyle and I hope it is around for years to come !

Thanx Again,
Walt C

[NXR]

I'm not certain the venting is adequate on any of the tanks, When we dump either gray or black the flow starts to slow down and then surges in the hose and you can hear it doing something in the tank(s). I need to close the dump valve halfway to stop the surging and noise from the tank and once it calms down I can open the valve fully and then it finishes up.

When our fresh water tank is full the water pump surges, fast-slow-fast-slow-fast-slow. If taking a shower with a full fresh water tank you can run out of pressure and the pump goes to a high-speed sound, as if its pulling against a vacuum. Turn the shower head off, the pump slows down and you have pressure again. If the fresh water tank is only half-full this does not happen.

Ray

[Dodge Guy]

Yes, they should be plumbed together. The gray is probably lower in e tank so you don't hear the water running.
Now we need to figure why someone would go through the trouble of installing a fake cap?

[Btm]

Originally Posted by NXR

I'm not certain the venting is adequate on any of the tanks, When we dump either gray or black the flow starts to slow down and then surges in the hose and you can hear it doing something in the tank(s). I need to close the dump valve halfway to stop the surging and noise from the tank and once it calms down I can open the valve fully and then finishes.

Ray

Mine does exactly same thing. I have thought it was some type of airlock, because the exit pipe diameter is 3 inch and the vents are smaller 1-1/2 or 2 inch. My reason for thinking this is because once it caused a flat spot about 2 foot long in the sewer hose.

Walter

Another thought -- Maybe it was being prepped for satellite, but then found out it was not an option ordered on this coach--better to leave the dummy hole than patch roof


Btm

[Scagsdale]

I’ve got a Georgetown 328 TS. The vent for the grey tank is in the cabinet under the bathroom sink. If I screw up and let that tank get too full, it will overflow out the shower drain.

[bubbles]

Originally Posted by Scagsdale

I’ve got a Georgetown 328 TS. The vent for the grey tank is in the cabinet under the bathroom sink. If I screw up and let that tank get too full, it will overflow out the shower drain.

Me thinks what you are referring to is the anti- siphon trap vent (possibly the black tank flush vacuum breaker/backflow preventer). If the gray tank vent was inside the unit your coach would always smell like a gray holding tank. Check your roof for at least 2 vents.

[bubbles]

Originally Posted by Walter Pigeon

Interesting... one vent... If this is your rig do you encounter the same back-up in the shower ? I had the DW run water while I listened at the vent pipe (Black) and heard nothing... if the used a common out let you would think you would hear running water. And why would someone put a phony second vent head up there ?

I have a GT378. These are just pictures of units like yours (same year and model) that I found to illustrate only one roof vent.

[Scagsdale]

Originally Posted by bubbles

Me thinks what you are referring to is the anti- siphon trap vent (possibly the black tank flush vacuum breaker/backflow preventer). If the gray tank vent was inside the unit your coach would always smell like a gray holding tank. Check your roof for at least 2 vents.

There is only one vent on my roof, and when the grey tank gets full, I smell it where the vent is.