No Nasty Surprises - RV Enthusiast Magazine

No Nasty Surprises

by | Aug 18, 2022 | Pro Tip, RVEXPERT

Adding an extra dump valve body can end messy sewer connections

Dumping the holding tanks can sometimes present unpleasant surprises, like getting a handful of contents when the cap is removed to attach the sewer hose. In a perfect world, the slides in the dump-valve bodies will prevent leakage when closed — but we don’t live in a perfect world. Sometimes a build-up of paper and other undesirable contents will keep the valve from fully closing.

Commonly, the dump valves on travel trailers and fifth wheels are mounted directly to the holding tanks and are fitted with remote handles, which can also be problematic (but that’s another story). Leakage from the dump valves can allow the contents to fill the termination pipe, and — you guessed it — end up on the ground and your hands when opening the cap before attaching the sewer hose.

The solution to avoiding embarrassing moments (if you prefer not to tear into the underbelly and repair/replace the existing dump valves) is to add a secondary valve body to the end of the termination pipe. With the slide valves closed, leaking waste will continue to back up in the pipe, but the added valve will block the contents from exiting the pipe until the T-handle is pulled — after the sewer hose is attached. And it’s easy to keep this valve clean, since it’s right out in front of you.

The first step is to make sure the termination pipe is clean (tanks dumped) before cutting off the existing bayonet flange, which accepts the sewer hose and cap. This can be easily accomplished with a hack saw. In most cases, there will be plenty of extra pipe to glue on a Valterra T1005 3-inch slip-hub flange, which will be bolted to a new Valterra T1003 VPM Blandex 3-inch waste dump valve body along with a Valterra T1009 3-inch bayonet flanged fitting on the other side. It’s just a simple matter of securing the three pieces, using the four bolts and nuts that were provided with the valve body. Just make sure the gaskets are seated properly and the nuts are not overtightened.

Once the outside of the termination pipe is cleaned with alcohol, a coating of ABS cement is applied to this surface, as well as on the inside of the slip hub. ABS cement sets up quickly, so you’ll only get a few seconds to orient the dump valve body with the attached fittings. The total cost for the three pieces was about $36.

the gasket is secured to the slip-hub flange
Adding a dump valve body to the end of the termination pipe makes sure you won’t be “treated” to a handful of waste. To start, the gasket is secured to the slip-hub flange that will be attached to the valve body before gluing to the existing termination pipe.
the twist-on valve body is replaced with the permanent valve
We already had the bayonet flange that was used on a previously attached twist-on dump valve body and retained for this project. The twist-on valve body was replaced with the permanent valve, which is much more secure — and won’t become dislodged at inopportune times.
all three pieces are bolted
All three pieces are bolted together before gluing on to the termination pipe. Overtightening the nuts can create leaks.
ABS cement is applied to the termination pipe
ABS cement is applied to the slip-hub fitting
After cleaning the surfaces with alcohol, ABS cement is applied to the termination pipe and the slip-hub fitting. ABS cement sets up very quickly, so you only have a few seconds to orient the T-handle to your liking.
full view of the newly installed dump valve with the T-handle is closed and cap attached
The T-handle is closed, cap is attached and you’re ready for the road. Just make sure to pull the T-handle after removing the cap and attaching the sewer hose.

Keep the new valve body slide closed and when it comes time to dump the holding tanks, simply remove the cap and attach the sewer hose before pulling the T-handle on the new valve body. No muss, no fuss — and you won’t get that dreaded handful of “icky stuff.”

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