Mascerator Exit Hose

Courtesy of Eugene Fisher

One feature of the 20-year-old GMC that is not better than current designs is the wastewater dump system. The Macerator pump was the first modification I made to my coach. The pump eliminated the terrible task of dumping the waste tank and turned it into a 2 min operation.

There are many pump mounting variations. I modified an Al Chernolf design that retained the original dump pipe for flushing and emergency clean out of material too large or hard for the pump. The one remaining nagging problem was the one inch exit hose from the pump. There are almost as many variations of the exit hose storage as there are pump installations. They vary from the hose wrapped around the bumper, multi-section hoses stored in side-storage to pumping into the exhaust system. The following is my solution for the hose storage problem.

Criteria

Easy and fast to use.
No additional hose required for normal operation.
Standard hose / attachments.
All controls / elements at the coach dump station.
Not visible from the outside.
Clean and no dripping.
Sealed system for RV sites.
Easy to back-flush the pump

The major problem with the hose is the requirement for a one inch hose. This is the size recommended by the pump manufacturer. This size hose does not allow the use of standard connectors and hoses. I finally gave up this requirement when I noticed the output from the pump is very liquid and reduction to a 5/8 inch or 3/4 inch hose would not cause a problem. This reduces the problem of flexibility and storage considerably.

I use a slot between the generator and the battery case for the hose storage. The hose is permanently attached to the pump. A 15-foot hose of either size will fit into this slot with about five feet used under the coach for attachment to the pump. This leaves about ten feet of hose to reach the dump station. I can usually park within this distance. However, a standard garden hose will attach to the pump hose for an emergency long distance pump-out.

The power switch is mounted on a small control panel attached to the battery box. The panel holds the waterproof pump switch, the tank flush hose (shown on the bottom of the bracket) and provides a stop for the hose bobbin. The power and fuse connections are at the far right of the battery box.

The hose-bobbin slides easily out over the control panel to remove the hose for pumping. A hose holder was necessary for easy removal and storage of the hose. The bobbin is square since the corners stick out to hold more hose and yet make it easy to push the hose into the storage slot.

The 3/4 inch hose shown is very flexible and I use a brass hose cap on the end to stop any drips during storage. The hose is easily wound and unwound from the bobbin during the dump operation. The assembly is light and easily slips into the slot for storage. Because the hose is permanently attached to the pump, the hose drapes over the control panel in the pump operation, and the control panel holds in the bobbin during travel. The hose assembly covers an access hole in the side of the generator case, but this hole is not a part of the generator cooling and is only used when the generator is extended on the sliders.

The dump process is very quick and easy. I would not say I dump every chance I get, however I will never again drive with a full waste tank.

Materials

Hose 3/4-5/8 inch flexible hose
Switch SPST water-proof switch 20 amps
Panel 3 inch X 2 inch aluminum angle
Fuse 15 amp in line fuse
Hose cap brass
Bobbin 2 ea. - 12 inch X 12 inch X 1/4 inch plastic (old carpet protector)
Blocks 2 ea. - 2 inch X 2 inch X 1 inch redwood spacer blocks

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Mascerator Exit Hose

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© 1998 by Patrick Flowers. All Rights Reserved

Revised 8/2/98