Up to 1.5 inches Man Hours .75
1.5-2 inches Man Hours 1.5
2-3 inches Man Hours 2
3-4 inches Man Hours 3
4-6 inches Man Hours 4
6-8 inches Man Hours 6
Over 8 inches Man Hours 8
Application:
This applies to approved backflow prevention devices installed in water lines to
prevent the backflow of treated water into the city water system. Check valves
or double check valves are not approved backflow preventers and are not included
for servicing under this guide.
Backflow preventers will normally be found in systems associated with boilers,
central chilled water units, cooling towers, and other systems where treated
water could backflow into the city water system. They also may be found in fire
protection systems.
Special Instructions:
1. Review manufacturer's instructions for testing the valve and the proper test
equipment involved.
2. Study the test procedures to be used.
3. Schedule maintenance on manually operated valves (PM Inspections
VLVMANML/CRIT-A & VLVMAN>2IN-5Y) in conjunction with this activity.
4. Schedule outage of equipment with operating personnel.
Items to Check & Initial Completion:
1.___ Secure the incoming city water line(s).
2.___ Test for objects lodged in seat or disc.
3.___ Test for worn or loose disc or disc guide assembly.
4.___ Check for damage to seat.
5.___ Check for corrosion build-up.
6.___ Following the manufacturer's procedures, check and calibrate as required.
7.___ Following the manufacturer's procedures, vent both chambers and return the
system to normal operations.
Tools and Materials:
1. Standard Tool kit.
Plus Pipe wrenches to 24"
Tubing cutters
Flaring tool
Small acetylene outfit
Packing tool kit and packing
3/4" socket set
Crescent wrenches to 14"
2. Cleaning equipment and materials
3. Lubricants
4. Manufacturer's testing and calibration kit.
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