Sniff test doesn't work

[HighwayJunky]

I have a 2015 Newmar Baystar and am looking to try a new black water vent for the roof. Problem, I have two vents on the roof and only one bath so I assume one vent is for the gray water. Both are basically side by side. So question is which vent is the black water vent..No smell jokes please..Tried it and that didn't work.

Thanks in advance.

[Snowman9000]

Jim@HiTek wrote:
Just get a bathroom PVC 'T' and put one on each vent. Only $8 total and you help avoid smells from either tank.

What is a bathroom T?



OR

[wa8yxm]

You should have a CLEAR piece Elbow or extension, somewhere in your Sewer Hookup.. Remove the broken cap or one cap.. Dump both tanks, leave Open one of the dump vales, have a partner watch the clear section while you shoot a garden hose sprayer into the hose (DO NOT INSERT HOSE INTO PIPE) if water runs That's the vent for the open tank. If it does not, after 2 or 3 gallons have partner open the OTHER dump vlave, if water runs than that is the tank you are watering.

That easy.

[Aridon]

Kayteg1 wrote:
If you have air compressor or leaf blower, you can stick air hose into the toilet with some rugs to seal it and then go on the roof and even with minimal flow, a piece of paper will show where the air comes out.
Thinking more - any vacuum with reverse hose will work.

I'm imagining some idiot hooking up a leaf blower to his outlet at the dump valve and the resulting **** geyser shooting out of the roof 🙂 Not sure why but I got a laugh.

[George_Beggs]

I just did my vents. I wasn't sure witch one was for the black tank so I did both. It can't hurt.

[cwit]

Drain both tanks empty, close both valves, put water hose down one vent. Let run for a few minuets. Shut off water go open black tank if you have water you found the black tank if not it is the gray tank.

[dougrainer]

Just put a pint of PINE SOL in the Black tank. That will allow the Pine Sol odor up its vent pipe. Doug

[Jim]

Just get a bathroom PVC 'T' and put one on each vent. Only $8 total and you help avoid smells from either tank.

[strudeau]

Been there done that. Had a fifth wheel a few years back that I was adding a SeeLevel tank monitoring system to. Had trouble figuring which tank was which because of limited access. So, I ran fresh water into the tank via the roof vent, see which tank fills.

[ArchHoagland]

Turn the water on in the sink and listen at each of the pipes.

Perhaps you may hear the water running into the gray tank.

[korbe]

You could empty one of the tanks, then go fishin and see if the bait (paper) comes back up wet.

[Kayteg1]

If you have air compressor or leaf blower, you can stick air hose into the toilet with some rugs to seal it and then go on the roof and even with minimal flow, a piece of paper will show where the air comes out.
Thinking more - any vacuum with reverse hose will work.

[ScottG]

You could dribble water down it while someone listens at the toity.

[rgatijnet1]

You should be able to put something in the black tank to cause an odor that you recognize as only being from the black tank. Try Pinesol, bleach, etc. Don't wait too long or it will dissipate.