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The Vacuum Holding Tank (VHT) system consists of a
VacuFlush toilet or EcoVac™ toilet and the Model VHT
Vacuum Holding Tank. The VHT is a unique combina-
tion of the vacuum tank, vacuum pump and holding tank
components used in a standard VacuFlush toilet
system.
VACUUM TOILETS
The VacuFlush 500 series features a large household-
size bowl and seat. The VacuFlush 1000 series also
features a deep bowl with an adult-sized seat. The
EcoVac series offers space-saving models with adult-
sized seats. All come with an attractive, easy-to-use flush
pedal.
The Vacuum Holding Tank (VHT) brings the
technology, comfort and efficiency of Dometic’s
renowned VacuFlush
®
vacuum sanitation systems to
smaller boats in an easy-to-use, and easy-to-maintain
package.
Simple Installation
• All system components are “installation ready.”
• No solvent bonding is required.
• Removable hose insert fittings make hose installation
simple.
• Vacuum pump and switch are pre-wired at factory.
• Easy to mount.
Reliability is Built-In
• No impellers or macerators. Motor can run without
burning up.
Each toilet series consists of several models, allowing
for a multitude of installation variations: a rear discharge
standard height unit, a bottom discharge standard height
unit, and a bottom discharge low-profile unit designed to
fit on a platform.
The vacuum toilet must be purchased separately;
it is not included with the VHT.
VACUUM HOLDING TANK (VHT)
The VHT produces and stores vacuum between flushes.
The vacuum holding tank is made of highly durable poly-
ethylene. The pump is integrally connected with
the vacuum tank. The vacuum pump is electric and draws
only 2 to 4 amps of current at 12 VDC.
One vacuum holding tank is required for each toilet.
Two or more toilets cannot be connected to one VHT.
The VHT contains the pre-set pressure differential switch
control that turns the pump on and off when the proper
level of vacuum is created.
A unique component on the VHT is the Vacuum Relief
Valve (VRV). The VRV prevents excessive vacuum from
accumulating in the tank. The VRV is calibrated to open
at 13" of vacuum and close at 11" of vacuum. This fea-
ture is beneficial during pump-outs.
The VHT system comes equipped with a full level float
switch. This float switch is wired directly to an automatic
shutdown relay. The relay prohibits the vacuum pump
from generating vacuum once the tank is full. A full level
indicator light should be wired to the full float, by the
installer. If a full level indicator light was not installed,
order part number 318714 from Dometic. The indicator
light is not part of the basic system.
VACUUM HOSE
To complete a VacuFlush installation, OdorSafe
®
Sani-
tation Hose or rigid PVC pipe (Schedule 40 or heavier)
must be used. OdorSafe hose is specially formulated to
provide up to 16 times greater resistance to malodors
than other “no-odor” marine hoses.
MAJOR COMPONENTS
PRODUCT FEATURES
TABLE OF CONTENTS
Product Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Major Components . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Principles of Operation . . . . . . . . . . . . . . . . . . . . . . . 3
System Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Component Locating Procedure . . . . . . . . . . . . . . . . 4
Key Installation Points . . . . . . . . . . . . . . . . . . . . . . . . 4
Installation of Components . . . . . . . . . . . . . . . . . . . . 5
Winterizing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Troubleshooting Guide . . . . . . . . . . . . . . . . . . . . 6 - 7
Dimensional Specifications . . . . . . . . . . . . . . . . . . . . 7
Manufacturer’s One-Year Limited Warranty . . . . . . . 8
