The Water Sump Control Valve provides the means of detecting free water accumulation in filter/separators, storage tanks and other refueling system components. The major functional components of the valve are the float, the valve, the sump and the plunger assembly.
A. Negligible Free Water Accumulation
When the accumulated free water in the sump is negligible, the specific gravity of the float is sufficient to keep it from floating, and the refueling system operates normally.
B. Excessive Free Water Accumulation
As free water accumulates, its higher specific gravity causes the float to move upward. When the free water accumulation is sufficient, float movement actuates its normally open valve closes and opens a path for the system reference pressure to vent. When this occurs, the refueling system shuts down due to the lack of reference pressure to its control valves.
C. Refueling System Restart
When the refueling system has been shut down due to excessive free water accumulation in the valve sump, operator action is required to drain the water. When the water has drained, the float will sink, the vent valve will close, and normal operation will resume.
D. Pre-Check Plunger
The pre-check plunger provides the means to verify proper operation of the valve. When the plunger is pushed, it manually lifts the float and operates the valve, causing system reference pressure to vent. An audible sound is produced when the system reference pressure vents. The pre-check plunger should be used periodically, in accordance with the operator’s established operating procedures.
E. Reference Pressure Source
The valve can operate with reference air or fuel pressure. Reference air can be vented to the atmosphere. Reference fuel pressure must be vented to a low pressure purge tank.