=A Check Valve= is the valve on the feed pipe between pump or injector
and the boiler. The check valve is so constructed that the pressure of
the feed water from the pump or injector lifts the valve from its seat
and the water passes into the boiler. Immediately after the pressure
from the pump or injector is released, the pressure from the boiler
closes this valve and prevents the water from being forced back into
the pump or injector. There are two check valves used in connection
with a pump, one on suction, the other on deliver pipe.
Q. How can check valves that get stuck open be closed?
A. By simply tapping them slightly with a light hammer.
Q. Should this be practiced?
A. No, when they stick at all they should be opened and thoroughly
cleaned as soon as pressure can be shut off.