N.1. Test methods - primary and secondary shut-off devices.

Examination of primary and secondary shut-off devices to determine the acceptability of an individual nozzle shall be performed using motor vehicles with fuel tanks and fill pipes representative of California vehicles and/or a field compliance test unit as specified in subsection S.2.

N.2. Test procedure - primary and secondary shut-off devices.

N.2.1 Initial test - primary shut-off device.

Dispense fuel into the fill pipe opening of a vehicle fuel tank or test unit in accordance with the instructions for the vapor recovery device, if any, and common public usage. The nozzle shall shut off automatically when the nozzle primary shut-off sensing mechanism is covered by the liquid. Automatic nozzle shut off shall occur with the dispenser operating at discharge rates both greater than and equal to the minimum rate allowed by the slowest hold-open clip setting, if any, or 3 gallons per minute, whichever is less.

N.2.2. Override test - primary shut-off device.

After the initial primary shut-off device activates, dispense enough additional fuel into the test unit to immerse the nozzle primary shut-off sensing mechanism in liquid. Record the dispenser indicator gallons. Make 6 additional, consecutive override attempts duplicating a full range of potential customer usage and record the new indicated gallons. All 6 attempts shall result in automatic nozzle shut off before the dispenser volume indicator increases more than the ¹/₁₀ gallon limit as specified in subsection T.1.1.

Note: A test unit must be used for this procedure so the primary shut-off device sensing mechanism can be seen immersed in liquid.

N.2.3. Secondary shut-off device (if equipped).

Introduce sufficient fuel into the vapor return line (approximately ¹/₁₀ gallon or 375 milliliter) to block the return of vapors through the line. Hold in place a “U-shaped” configuration of the fuel discharge hose at a level lower than the nozzle to concentrate the liquid. Make one or more attempts to dispense fuel into an empty test unit or vehicle fuel tank that is within 3 gallons of being full, including the fill pipe. (Balance-type nozzles must make their intended tight seal at the fill pipe opening.) The nozzles shall shut off automatically before the dispenser volume indicator increases more than the ³/₁₀ gallon limit for each attempt as specified in subsection T.1.2.

N.3. Assist systems.

To test assist systems for proper operation at the specified inches of H₂O column vacuum, refer to Section 4054.2, N.5.