How to Repack a Fire Hydrant

Fire hydrants are a familiar and simple looking piece of crucial equipment. When it comes to saving lives or property with water, the hydrant is the key to success. A fire hydrant must be maintained and kept in good working order to be ready when needed. The work of repacking a fire hydrant keeps the inner parts in operable shape. This should always be performed by a professional firefighter or technician certified to do the work.

Things You'll Need

• Spanner wrench
• Hydrant wrench
• Regular wrench set
• Seat wrench
• Flat-head screwdriver
• Seat ring
• O-rings
• Flanges (optional)
• Food grade non-petroleum valve grease or hydrant lubricating oil
• Torque wrench

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Instructions

• 1

  Turn off the water main to the hydrant. Fire hydrants vary somewhat in design, and these instructions apply to a dry hydrant (the water does not sit inside its barrel or body).

• 2

  Open the hydrant nozzle cap with the spanner wrench to release any pressure or water in the line, then close the cap.

• 3

  Remove the weather cap with the hold down screw(s), if applicable.

• 4

  Turn the thrust nut, or hold down nut, by turning clockwise with the hydrant wrench.

• 5

  Twist to loosen, and then remove the operating nut from the top of the hydrant with the hydrant wrench. Slide the bonnet assembly sleeve down over the stem to protect the o-ring seals. Detach the bonnet, removing the bolts and nuts with the regular wrenches that coordinate to the size on the hydrant.

• 6

  Unscrew the seat ring using the seat wrench from your fire hydrant manufacturer. Lower the hydrant wrench over the upper stem. Adjust the guide to fit the nozzle section opening, lock the wrench into place with the set screw, then replace the operating nut. Turn the wrench to loosen the valve stem and assembly.

• 7

  Remove the operating nut and wrench assembly. Life out the entire valve assembly. Dismantle the main valve assembly, the upper valve, plate valve, and valve seat ring. Use the wrench to remove the bottom nut and disassemble the rings using the screwdriver to pry them apart, if necessary. Replace the seat ring. Re-bolt the plate and upper valve with the stem nut back onto the stem. Lubricate the threads of the valve assembly.

• 8

  Place the seat wrench back over the stem, and put the operating nut in place to secure it. Lower the valve assembly back into the barrel of the hydrant, adjust the seat wrench to fit the opening, and tighten the set screw. Turn the wrench to tighten the valve assembly back into place.

• 9

  Slide the bonnet assembly sleeve over the stem. Lubricate the sleeve to coat the o-ring seals. Replace the bonnet gasket, adding lubricant to the seal. Put the bonnet back in place over the stem, and then put the bonnet bolts and nuts into place, finger tightening them. Remove the bonnet assembly sleeve.

• 10

  Replace the thrust nut, or hold down the nut and tighten to 75 foot/pounds of torque with the torque wrench. Replace the weather cap and tighten to 25 foot/pounds of torque. Tighten the bonnet bolts and nuts evenly, to 75 foot/pounds of torque minimum.

• 11

  Loosen one hose nozzle cap, then turn on the water and charge the hydrant fully. Tighten the nozzle cap back down when the water begins to flow, and check the hydrant for leaks. Close off the hydrant, release the nozzle cap to drain the hydrant, then re-close when the hydrant is empty.