Which pipe is which????

[kittyfixer]

Hi,
I have a 2006 Coachmen Spirit of America RV. I'm trying to put a rotating vent on top of my black water tank pipe on the top of my RV. Unfortunately, I'm very new to all of this, and I'm not sure which pipe is which. I know one is for the grey water tank, but they both look exactly the same. Any help would be greatly appreciated.

[curveballer98]

the vent for my black is pretty much in a straight line up from the toilet and the grey is above the shower and the galley tank vent is a bit more forward... at least on our trailer.

[kittyfixer]

Thanks so much for all the good advice. I've only owned the RV for a few weeks, so everything is trial and error.

[Dutch_12078]

Before dumping anything down the vent pipe, make darn sure it IS a sewer vent! Some RV's have a second vent cap that serves the "attic" air space between the ceiling and roof. Not a great place to be dumping in water... 🙂

[myredracer]

Another option would be to have someone flush the toilet and put your ear near each vent to see which has a running water sound. If you can't get close enough on the roof to the vent, you could put a length of hose into the vent and listen to the end of it.

Could also dump some food dye down the vent to see which outlet it comes out of.

[wa8yxm]

RoyB wrote:
Probably the only sure way would be go up on top and take a big whiff of it...

You can always call the manf with your VIN number handy and ask them.

Roy Ken

And the one that stinks LEAST, more often than not, is the black tank.


Here is a positive way to do it....

Get one of those clear extensions so you can see the dump and put it in line with your hose.. I like to put it at the RV end.

Dump tanks and CLOSE VALVES.

now, take a couple gallons (or a hose) up on the roof with you and run/pour some water into ONE of the vents, Just one, not both.

Go back down and open first the BLACK tank, if it dumps a bunch of mostly clear water.. You have a lead.

Then open the gray, if it dumps nothing, You have your answer

On the other hand if the black tank dribbles and the gray gushes.. Well, then you have the other answer.

[DougE]

Close the gray tank drain valve. Open the black tank drain valve. Stick a water hose in the top of the vent pipe and turn it on slow. If water comes out the drain you've found the vent for the black tank.
BTW, the vent pipes are primarily installed to prevent a vacuum being formed when water runs down the drain. Without the vent, the vacuum would pull the water out of the p-trap then allowing sewer gases to come up through the sink or toilet. Thus the use of air admittance valves at sinks difficult to reach with a vent.

[DiskDoctr]

Run a good slurp of bleach down the kitchen sink before doing the sniff test. The contrast should be obvious, even with a new camper.

PS- Usually good practice to avoid putting weight on roof unless absolutely necessary.

[kittyfixer]

Thanks for all the advice. The pipes are both directly above my bathroom, and look exactly the same. I guess I'll try to sniff test, or buy another vent.
Thanks again.

[1492]

Moved from Forum Technical Support

[Altern]

harold1946 wrote:
Put one on each vent. That will cover you when water in the p-traps evaporate.
Grey water can become just as offensive as the black.

X2

[Mark_Heisler]

Your black vent should be the one closes to your bathroom and the grey should be the one in the kitchen area when on the roof.
That the way mine FW is

[RoyB]

This is all too funny - I'm married to a full blown TEXAS GAL. She drives a big white Cadillac with TEX on the plates - They shoot first and ask questions later. You know who would be going to the roof here... SNIF SNIF..

Roy Ken

[Dog_Folks]

kittyfixer wrote:
Hi,
I have a 2006 Coachmen Spirit of America RV. I'm trying to put a rotating vent on top of my black water tank pipe on the top of my RV. Unfortunately, I'm very new to all of this, and I'm not sure which pipe is which. I know one is for the grey water tank, but they both look exactly the same. Any help would be greatly appreciated.

We faced the same problem last summer. Not only are the pipes on our roof identical, they are within one foot of each other.

After many suggestions here, we decided on the "sniff" test.

The DW went on the roof,(I am disabled,) and sniffed each pipe. It was very obvious which was which.

Problem solved. Quick and easy. No special equipment needed.

P.S. While she was up there, she also installed the rotating vent.

[nomad297]

What RoyB said. You can also have somebody yell into the toilet while you're on the roof.

Bruce