The FX Leak Detector 3-Step Test
Manifolded Pumps with Leak Detectors
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2.
Leak Sensing Position (Metering)
As the pressure builds to approximately 8 to 16 psi (55 - 110 kPa) (rapidly) the diaphragm has moved the
poppet to such a position as to almost stop the flow into the piping through the LLD valve poppet. In this posi-
tion, all the flow must then travel around the metering pin which limits it to approximately 3 gph (11 lph) rate. If
a simultaneous loss from the system equals or exceeds this amount, the line pressure will not build beyond
this point and the valve will remain in the leak sensing position with the main flow blocked. If there is an at-
tempt to dispense while the valve is in this position, the line pressure will drop, the diaphragm will respond,
and the poppet will return to Position 1 where the 1-1/2 to 3 gpm (5-11 lpm) will flow to the dispensers. Leaks
smaller than 3 gph will be indicated by the LLD taking longer than 2 - 3 seconds to open completely. If there is
no leakage in the system, the small flow around the metering pin increases the line pressure to 12 - 16 psi (83
- 110 kPa) in approximately two seconds at which point the diaphragm will snap the poppet to Position 3. This
all takes place in less time than it takes to reset the dispenser, walk to the car, remove the gas tank cap, insert
and open the nozzle.
3.
Non-Leak Position (Open)
This position allows full flow. The poppet will remain in this position as long as the system pressure remains
above 3 to 5 psi (21-35 kPa). At less than 3 to 5 psi, the poppet will return to Position 1 and the next time the
pump is activated, the LLD will perform a line test.
Per the above process, this product is designed and sold to detect leaks of 3gph (11 lph) or greater
only. For leaks of less than 3 gph, please consult with your V-R Company Representative.
NOTE
