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 Dry Barrel Hydrants feature a safety Breakable Flange (F33) and Breakable Stem Rod Coupling (F37) design. This allows the hydrant head assembly to be struck by a vehicle and “Break Away” reducing the impact to the water main. In the event the hydrant head assembly has been broken away, the following repairs will be necessary.
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. In the event of a vehicle collision or break away, locate and be sure the supply valve is closed. After reassembly, 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 hardware (F30,31,34) from the Breakable Flange (F33). Slide the Lock Ring (F32) off of the Lower Barrel (F49). (See Fig. 8)
2. Remove the Spring Pins (F38) from the Coupler Pins (F36) in the Upper Stem Rod (F16) and Lower Stem Rod (F41). Remove and discard the broken Breakable Coupling (F37).
3. If required, remove the Upper Stem Rod (F16) from the hydrant head assembly by following the Warnings and steps 1 through 4 in the MAIN VALVE INSPECTION section on page 14.
4. Re-connect the Upper Stem Rod (F16) to the Lower Stem Rod (F41) with new Coupler Pins (F36), new Breakable Stem Rod Coupling (F37), and secure with Spring Pins (F38).
NOTE: For hydrants manufactured prior to Sept. 7, 2010,
the Breakable Stem Rod Coupling should replaced with the
arrow pointing up. For hydrants manufactured after Sept. 7,
2010, there is no orientaion. (See Fig. 9)
5. Slide a new Breakable Flange (F33) over the Lower
WARNING: Be sure the Breakable Flange(F33) is right side
up, indicated with the text “This Side Up”, facing towards the
nozzle section. (See Fig.8&9) . Slide a new Lock Ring (F32)
into the groove on the Lower Barrel.
6. Clean the hydrant’s Nozzle Section/Upper Barrel and
Lower Barrel flange face and install a new Barrel Gasket
7. Lift the hydrant Modern Head (F29) and Upper Barrel (F35), assembly over the Upper Stem Rod (F16) taking care not to
dislodge the Stem Seal O-rings (F15), or Barrel Gasket (F17).
8. Check for correct alignment of the Barrel Gasket (F17) and re-install the nozzle section mounting hardware (F30,31,34)
9. Using the AVK Seat Wrench, install the Stop Nut (F11). Do not over tighten the Stop Nut! Fill the lubrication reservoir with the appropriate food grade oil or grease that contains no acetate or silicone.
10. Place one Anti Friction Washer (F8), on the top and bottom of the Operating Nut (F10) thrust collar. (See Fig. 7A)
11. Install the Operating Nut and Anti Friction Washers.
12. Lightly grease the o-rings on the Thrust Nut (F6), and screw the Thrust Nut into the Bonnet completely, then back off the Thrust Nut 1/8 to 1/4 turn, until the Thrust Nut lines up with the Lockplate (F4).
13. Install the Lockplate and secure it with the Lockplate Screw (F3), using a 7/64″ or (3mm), hexagon key.
14. Tighten the Nozzle Section mounting hardware to 80 Ft. Lbs.
15. Install the Weathershield and Weathershield Bolt using a 5/16″,(8mm) hexagon key.
16. After reassembly is complete, open the supply valve and test the hydrant for leaks.