Fleetwood 1999 Discovery Parts And Service Manual page 93

If the drain system does get clogged:
»
Use a hand-operated probe to loosen stubborn accumula-
tions.
»
Seriously clogged P-traps may require disassembly. Be careful
not to overtighten when reassembling.
»
Do not use harsh household drain cleaners.
»
Do not use motorized drain augers.
»
Sometimes the holding tank valve will get clogged. In this
case, a hand-operated auger may be necessary. Be ready to
close the valve quickly once the clog is cleared. If the seal
gets damaged, it is easily replaced.
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