MAIN VALVE INSPECTION
WARNING: For all of the following repair procedures, the hydrant must be isolated or the system depressurized and drained before removing the hydrant components. Failure to do so may cause pressure to be released resulting in severe injury or death.
AVK Hydrants are designed to allow all internal components to be easily removed without displacing installation.
WARNING: On a partially disassembled hydrant under line pressure, pressing down on the stem could force open the Main Valve (F61) and allow it to slam shut, creating a water hammer. If the intention is to remove the Main Valve (F61) first locate and be sure the supply valve is closed. Relieve the pressure on the Main Valve (F61) by momentarily opening and then closing the hydrant. Reopen the supply valve after the hydrant has been reassembled.
1. Remove the Weathershield Bolt (F1) with a 5/16″,(8mm) hexagon key. Lift off the Weathershield (F2). (See Fig. 7A)
2. Remove the Lock Plate Screw (F3) and Lock Plate (F4) with a 5/32″ or (4mm), hexagon key.
3. Using the AVK operating wrench, or a large adjustable wrench, unscrew the Thrust Nut (F6) counterclockwise. (See Fig. 7A &7B)
4. Remove the Operating Nut (F10) using the AVK operating wrench. Turn counterclockwise for “Open Left Hydrants”, and clockwise for “Open Right”, hydrants. Remove the Anti Friction Washers (F8), and set aside with the Operating Nut. (See Fig. 7C)
5. Remove the Stop Nut (F11) with the deep socket located at the end of the AVK seat wrench. CAUTION: Do not overtighten the Stop Nut (F11), during re-assembly! (See Fig. 7D)
6. Remove the six Bonnet Bolts (F12) and associated hardware using 3/4″ or 19mm wrenches. Lift Bonnet (F14) over the Upper Stem Rod (F16) and set aside.
NOTE: On oil filled hydrants, to avoid draining of oil from the oil reservoir in the bonnet (F14), press the Oilsaver sleeve (See Fig. 7E and 7F), with the stop ring placed downward) over the Upper Stem Rod (F16) during the disassembly. While holding the Oilsaver in place, lift the Bonnet (F14), and Oilsaver off of the Upper Stem Rod (F16). During reassembly inspect the Stem Seal O-rings (F15) and the Barrel Gasket (F17) for damage.
7. To remove the Valve Seat Ring (F51) and Main Valve Assembly, Slide the AVK Seat Wrench ( Fig. 7G) over the Upper Stem Rod (F16) and engage the seat removal pin. Turn the tool counterclockwise, (approximately 6 turns) until the Valve Seat Ring has disengaged from the Drain Ring (F54). NOTE: For deeper buries, and optional AVK Seat Wrench Alignment Tool is available. (See Fig. 7G)
8. Remove tool and set aside. Lift and remove the Upper Stem Rod / Lower Stem Rod and Main Valve Assembly from the Lower Barrel (F49). (See Fig. 7H)
9. Inspect the Main Valve (F61), Valve Seat Ring (F51), Valve Seat O-rings (F53) for damage. Replace if necessary.
10. If any of the above parts are to be replaced, clamp the Lower Stem Rod (F41) in a standard pipe vise. (See Fig. 7J) Slide the Valve Seat Ring (F51) off the ears of the Main Valve. To disconnect the Main Valve from the Lower Stem Rod (F41) remove the Spring Pin (F38), and Main Valve Retaining Pin Washer (F88), from the Main Valve Retaining Pin (F60). Reverse the steps for reassembly. Lightly grease the Main Valve ears and Main Valve O-rings (F53), with a food grade grease that contains no acetate or silicone.