THOR Jayco Precept 2021, Owner'S Manual, Page: 128 / 173

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Section 8: Plumbing System
Drain Pipes with Dry Sealing Valve (if so
equipped)
Your RV may be equipped with a dry sealing valve
that prevents the escape of odors from your waste
system and eliminates the need for P-traps. Should
the RV drain piping system become clogged, it is
important that the dry valve be removed before
passing a mechanical cleanout tool through the
piping to open the drain. Passing a cleanout tool
through the waterless valve may cause damage to
the internal seal that may potentially allow sewer
gases to escape into the RV interior. The waterless
trap can be unscrewed from the water lines. A label has been placed near the location of the
waste valve that reads as follows:
Sewer Hose Storage
Depending on your RV model, the sewer drain hose may be stored in an exterior compart-
ment marked “Sewer Hose” or it may be located in the hollow square tube bumper. The
bumper has removable plastic end caps, and the hose slides inside the hollow bumper.
Vents
Vent pipes and vents release air from the grey and black water holding tanks. On most mod-
els the exterior vent cap is attached to the roof and must be kept clear of obstructions to
perform as intended.
On some models, the vent pipe may be part of the drainage system referred to as a “wet
vent” where water flows downward as air flows upward
in the same pipe.
Some models are equipped with a side vent system. On
these models this label will be next to the termination
valve. This label should not be removed from your rec-
reation vehicle.
Black/Grey Water Holding Tanks
Dump the gray and black water holding tanks before traveling to avoid carrying unnecessary
weight. The weight of the holding tank contents is not calculated into the RV cargo carrying
capacity. Traveling with full holding tank(s) could cause you to exceed the individual tire
ratings and/or the RV GAWR or RV GVWR. Potential damage to suspension components,
such as springs, tires and axles, could result.
If you are dry camping and cannot immediately empty your holding tanks, reduce your
vehicle speed until you reach a dumping station. When connected to the sewer drain line at
a campground, keep the black tank drain valve closed until the holding tank is at least ¾ full.
This will provide sufficient water to assist in complete draining of the black water holding
tank. Repeat as needed.
Before using the recreation vehicle, or after dumping the grey and black water holding tanks,
always add the proper amount of deodorant to the black water tank to prevent odors and
help break down holding tank contents (unless winterizing). Follow the deodorant bottle or
package instructions. Driving to a disposal site will normally loosen any accumulated waste
debris or solids from the sides of the holding tanks.
REMOVE WATERLESS TRAP BEFORE
USING MECHANICAL DRAIN CLEANING DEVICES
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