Dometic 500Plus Series - Manual (Page 12)

TROUBLESHOOTING GUIDE
13.Vacuum pump is running too
slow, overheating, blowing
fuses or circuit breaker.
14.Toilet will not flush.
(No vacuum.)
See problems 3 and 15
if necessary.
15.Blockage between toilet and
vacuum generator.
16.Pump emits odor.
a. Gear motor is worn or defective.
b. Plugged vent line or vent filter.
c. Blockage in discharge line.
d. Improper wire size.
e. Improper voltage.
f. Vacuum pump bellows clogged
with tissue.
a. There is a blockage in the system.
b. Pump will not run.
c. Duckbill valves in vacuum pump
are inverted due to blocked
discharge line or an attempt to
pump out against closed seacock.
a. Collapsed vacuum line.
b. Sharp bends or kinks in vacuum
hose.
c. Improper operation of toilet.
d. Foreign objects were flushed down
toilet.
a. Loose or defective hose
connection on pump.
b. Loose intake or discharge fittings
on pump.
c. Worn, torn or punctured pump
bellows (vacuum generator) or
diaphragm (vacuum holding tank).
a. Check motor and replace if
necessary.
b. Disassemble and clean out vent
line. Replace vent filter if
necessary.
c. Disassemble and clean discharge
line. Be certain that in-line valves
(duckbill valves) and seacock are
in proper position.
d. Wire size too small. Check
electrical diagram for proper wire
size for voltage of pump used.
e. Check input power for low voltage.
f. Remove and clean bellows
assembly. (When flushing toilet,
using more water may alleviate
this problem.)
a. Open flush ball and check the 1-
inch (25mm) orifice at the bottom
of the base for blockage and
dislodge it. Never use drain-
opening or other household
plumbing chemicals.
If blockage is not in base, it may
be found in these locations:
• outlet of vacuum tank
• inlet of vacuum generator
• diptube of vacuum generator
• inlet of vacuum pump
b. See problem 12.
c. Replace duckbill valves, making
sure they point in the correct
direction.
a. Inspect vacuum line for collapsed
condition and replace line if
needed.
b. Inspect vacuum hose for kinks or
bends. If less than 8.5-inches
(216mm) radius on any bend,
reposition hose to achieve
minimum 8.5-inch bend radius.
c. Make sure each person using
toilet knows correct procedure.
d. DO NOT flush any non-dissolving
items (i.e. sanitary napkins, facial
tissue, wet strength tissue, paper
towels, etc.) or excessive toilet
tissue down toilet. Rapid-dissolv-
ing SeaLand brand toilet tissue is
best.
a. Tighten connections or replace
hose and make new connections.
b. Tighten intake or discharge fittings
on pump. Replace nipples or
adapters if necessary.
c. Replace pump bellows or
diaphragm.
Problem Possible Cause Service Instructions
12