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Appendix B <br />71SO Overfill Valve In Tank Shut Off Level <br />Worksheet <br />Important: This is meant to be a supplemental <br />worksheet and not a substitute to following the <br />installation manual instructions. All length <br />measurements are in inches. Please contact the <br />Authority Having Jurisdiction (AHJ) and review <br />local, state, and national codes to determine the <br />regulatory requirements governing shut-off <br />capacity in your region, as well as take into <br />account other considerations such as extreme <br />tank tilt. <br />With valve installed in the tank take the following <br />measurements: <br />Distance from the 71SO inlet tube flange to the cast <br />lug in the 71SO body (see figures), upper tube <br />length. Note: the Upper Tube Length must be at <br />least 16” to include the protective bend in the tube. <br />(D) = _________ <br />Distance from the 71SO inlet tube flange to the top <br />and bottom of lower tube, valve length. <br />(W) = ___________ <br />(U) =____________ <br />Distance from the 71SO inlet tube flange to the <br />bottom of the tank. Note: If a tank bottom protector <br />is present it may be necessary to add this thickness <br />to dimension (OPW 6111 & 61TP models add 0.6”) <br />(B) = _____________ <br />From the tank calibration chart provided by tank <br />manufacturer find the dipstick number (Y) which <br />corresponds to the 100% volume. <br />(Y) = _____________ <br />1. To determine shut-off percentage: <br />Subtract upper tube length (D) from distance to <br />tank bottom (B) <br />(X) = (B) – (D) - 2” =_________________ <br />Using the tank calibration chart provided by the <br />tank manufacturer determine the tank capacity at <br />the calculated (X) dimension and the 100% volume <br />(Y) tank capacity. <br />tank capacity in gallons =__ <br />tank capacity in gallons = ______ <br />SO% = (X) capacity / (Y) capacity x 100 = _ <br />Note: The overfill valve must be installed per AHJ <br />requirements and all applicable local, state, and <br />national codes. If overfill valve is set above the <br />allowable shut-off percentage the overfill valve <br />must be removed and replaced. For reference 40 <br />CFR part 280 Subpart B Section 280.20 overfill <br />valves should be set to a maximum of 95%. <br />(B) <br />To Tank <br />Bottom <br />(D) <br />Upper <br />Tube <br />Length <br />(W) <br />Valve <br />Length, <br />bottom of <br />cut <br />(Y) <br />Tank <br />Chart <br />100% <br />Volume <br />Dipstick <br />Number <br />(U) Valve <br />Length, <br />top of <br />cut