Ames Fire & Waterworks 6000HMB Portable Hydrant Meter Backflow Preventers with Meter Housing - Manual (Page 4)

4
Relief Valve Service Instructions
WARNING ! Depressurize valve before servicing.
The relief valve may be serviced while on or off the backflow pre-
venter valve.
NOTICE
Do not use a pipe wrench to remove the relief valve assembly
from the backflow preventer.
Relief Valve Disassembly
1. Disconnect the relief valve hose from the elbow in the bottom
flange cover at the swivel hose connection. Do not remove the
elbow.
2. If the valve is to be removed from the backflow preventer for
service, place a screwdriver blade or flat bar across the edges
of 2 of the hex head screws in the bottom flange cover and
turn counterclockwise to loosen the relief valve assembly. (see
Figure 2)
3. Remove the 4 bottom bolts from the bottom of the relief valve
assembly with a 5 /
16
" socket or open-end wrench. Remove the
bottom flange cover.
4. Remove the piston assembly & sleeve from the relief valve body
by placing your index fingers through the slots in the side of the
body and pressing down on the top of the disc retainer in the
top of the piston assembly. (See Figure 7.)
5. Pull the piston assembly free of the body by grasping the sleeve
and pulling down.
6. Grip the sleeve and the piston assembly by the head of the hex
head bolt. Pull up on the sleeve to extend the diaphragm. Slide
the sleeve (Part #7013340) completely off of the diaphragm and
inspect the diaphragm for tears, holes or excessive wrinkles. If
the diaphragm is damaged, order a new piston/diaphragm as-
sembly.