BC Transit – Air Brake Course

One-way Check Valve
The one-way check valve is situated between the wet tank and the dry tank.
This is the first defence against a catastrophic air loss. If the main discharge line
ruptured or the wet tank were punctured, the one-way check valve will not
allow the air pressure to flow backwards out of the dry tank.
When draining the reservoirs, always open the drain valve of the wet tank first.
If there is still pressure in the dry tank, you know the one-way check valve
worked.
The check valve is a common valve in the air brake system and is used at many
other locations and for different applications.
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