Airstream 390 - Manual (Page 70)

G
PLUMBING
G - 24
BLACK TANK FLUSH
The black water holding tank must be flushed out until all paper and waste material is
removed. Close the dump valve and refill the tank with 5 to 10 gallons of clean water
and repeat until clean.
In the utility compartment on the left side is a water hose connector marked “Black
Tank Flush.” It allows water to flow only one way. To use, hook-up hose and turn on full
force. Within the tank a spray head with a multiple- holed head will spray the interior
surface of the tank.
The gate valve should be closed for the first couple of minutes, and then opened to let
the water out in a rush. Repeat as needed.
Drain Systems Cleaning
There are many deodorizers on the market in tablet, liquid, and powder form. These not
only combat odor, but also, stimulate the bacteria that works to dissolve the solids in
your tank. Picking a deodorizer with lubricating qualities will ease slide valve operation.
The only cleaning agents that can be used without causing harm to the system are
household ammonia and tri-sodium phosphate in small quantities. Do not use any
product that contains any portion of petroleum distillates. This attacks the rubber seals
of your toilet and dump valve. Also, do not use any dish detergent or abrasive cleaners.
All products should be marked approved for ABS drainage systems.
When winterizing drains use only recreational vehicle plumbing type antifreeze. These
are sold through your dealer.