8
Cleaning, winterizing
Dometic Vacuum Holding Tank
8
Cleaning and winterizing
8.1 Cleaning
A small amount of water remains in vacuum holding tank at all times, so it is good practice to rinse the
VHT completely after contents have been discharged .
1 . After initial pump-out, add holding tank deodorant or cleaner to toilet bowl, and flush with water .
2 . Continue flushing and pumping out tank until holding tank discharge is clear .
8.2 Winterizing
Use only propylene glycol freshwater antifreeze to winterize the holding tank .
Make sure the
antifreeze does not contain alcohol.
1 . Pump out the holding tank .
2 . Thoroughly flush system with fresh water before adding propylene glycol freshwater antifreeze to
the holding tank .
Caution!
Never use ethylene glycol automotive antifreeze in freshwater systems .
9 Troubleshooting
Problem
Possible Cause
Service Instruction
1 . Vacuum pump running too much
between flushes .
a . Flush ball in toilet leaks .
b . Vacuum line leak .
c . Foreign material has fouled
vacuum pump valves .
d . Pump diaphragm worn or
damaged .
e . Duckbill valve in discharge fitting
stuck open .
a . Refer to VacuFlush toilet manual
for information .
b . Tighten all hose connections at
vacuum holding tank and toilet .
c . Disassemble vacuum pump and
inspect under the two flat disk
valves . If foreign material is
present, remove it and
reassemble pump .
d . Inspect diaphragm in pump
for small hole or rip . Replace if
necessary .
e . Disassemble discharge outlet
and inspect duckbill valve . Clean
or repair if necessary .
2 . Toilet will not flush (no vacuum) .
a . Vacuum pump will not run .
b . Plugged vacuum discharge line .
c . Plugged vacuum pump valve .
d . Vacuum pump discharge or
intake lines plugged .
a . See problem 3 .
b . Blockage usually at base of toilet
below flush ball . Disconnect line
and clear .
c . Inspect and clean pump valves .
Replace if needed .
d . Disassemble lines and clean .
