Odor Eliminator

If you’ve ever flushed an RV toilet while running a vent fan, you know what I mean. I recall arriving at a campsite with the motorhome sealed up. I was extending the slideouts when a guest flushed the toilet, lowering the air pressure in the coach. Higher pressure in the holding tank forced odors into the living area, causing everyone to quickly move outside for some fresh air.

Smelly gases tend to stay in the holding tanks until they find a way to exit. A number of products are designed to assist with this. Fixed venturi vents can expel gases, but only when the motorhome is moving and air passes over the vent opening. Powered fans are another option, but they require a bit of installation and wiring, plus they use electricity. One of the most successful products is the 360 Siphon RV vent cap, which is distributed by Lippert Components.

The 360 Siphon, even with minimal breeze, creates a low-pressure area in the vent stack; the result is that fumes, which are under higher pressure in the holding tank, are drawn out through the 360 Siphon. The patented design can produce only an updraft, so wind will not pressurize the holding tank and force the odors into the motorhome.

The 360 Siphon is effective when the RV is standing still as well as when it’s moving. The device operates in 360 degrees, so the direction of the breeze doesn’t matter.

The 360 Siphon has a bug screen to prevent mud daubers or other insects from entering the vent pipe and building nests. And, best of all, it has no moving parts and is maintenance-free. It fits standard 1 1/2-inch or 2-inch vent stacks.

According to the product description, the 360 Siphon eliminates the need for holding tank chemicals because it creates an oxygen-rich tank environment that speeds waste breakdown. Holding tank chemicals can take up to 48 hours to fully oxygenate a tank, but the 360 Siphon begins the process immediately.

After hearing positive comments from other RV owners, I bought two 360 Siphons while attending FMCA’s summer 2015 convention in Madison, Wisconsin.

Installation was fairly easy. I began by removing the existing vent caps, which were flanged collars with steel caps that covered the vent pipe; air passed through around the edges. I used a razor blade scraper to remove the sealant that covered the flange, and then I used a power screwdriver to remove the screws that held the vent caps to the fiberglass roof. I then cleaned up all of the old sealant from the roof surface. For an EPDM (rubber) or TPO (flexible plastic) roof, it’s advisable to remove the sealant with a heavy-duty plastic scraper to reduce the chance of roof damage.

On many vent systems, the vent pipe protrudes a few inches from the roof. The 360 Siphon requires the vent pipes to extend no more than 5/8-inch above the roof, so I wrapped a piece of blue masking tape around the vent pipe and marked it at 5/8-inch. I then used a multitool to cut the vent pipe and remove the excess length. After a bit more cleanup, the area was ready for the 360 Siphon.

I pressed the 360 Siphon’s funnel-shaped collar over the vent pipe to create a tight seal with the vent cover. The 360 Siphon comes with a small roll of rope sealant. This putty-like sealant is used to seal the flange of the 360 Siphon to the roof. I carefully applied the sealant around the bottom of the mounting flange and placed the 360 Siphon over the vent pipe and onto the roof.

I then reused six screws from the original vent collar to secure the 360 Siphon’s mounting flange, which was predrilled for those screws. The screws went through the fiberglass roof and into the 3/8-inch plywood beneath, so there is no way they will fall off.

I didn’t feel that the sealant beneath the flange was quite enough to guarantee a leakproof seal, so I ran a ring of self-leveling sealant over the screw heads and covered the mounting flange of the 360 Siphon to prevent any possible water intrusion into the motorhome. I cleaned up the area, and I was done.

Because I haven’t yet forsaken my holding tank chemicals, I haven’t been able to evaluate the claim that the 360 Siphon breaks down waste without them. But whether it’s used with or without chemicals, the 360 Siphon seems to draw odors out of the holding tanks. The device is inexpensive, easy to install, and requires zero maintenance. It should be a good solution for RVers who wrestle with those troubling odors.

I installed a first-generation 360 Siphon. A newer version, the 360 Siphon Gen 2, is slightly smaller and offers another installation option: The existing cap base can be used if the installer believes it is still in good condition. The 360 Siphon Gen 2 functions the same, and may even do a better job of siphoning gases, according to the inventor. Like the original, the 360 Siphon Gen 2 costs about $30 and can be purchased online or at many places that carry RV accessories. The product is available in white or black.

3501 County Road 6 E.

Elkhart, IN 46514

(574) 537-8900