1. The relief valve may be serviced while on or off the backflow
preventer valve.
2.
Note: Do not use a pipe wrench to remove the relief valve
assembly from the backflow preventer.
3. Shut down water system.
Relief Valve Disassembly
1. Disconnect the relief valve hose from the elbow in the bot-
tom 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 screw driver blade or flat bar across
the edges of (2) of the hex head screws in the bottom
flange cover and turn counter-clockwise 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 assembly.
Relief Valve Reassembly
1. Thoroughly clean all inside surfaces of the relief valve body.
2. Inspect the relief valve body seat surface located at the
top edge of the (3) discharge slots near the top of the
body by rubbing the end of the index finger around the
entire seat surface; access the seat surface through the
slots or the bottom of the body. The seat must be free of
nicks. If nicks are discovered, remove the body & install a
new relief valve assembly.
3. Position the diaphragm on the piston assembly so that it is
facing up as shown in Figure 8.
4. Now fold the top (ribbed) edge of the diaphragm inward,
grasp the sleeve with the ribbed edge up and slide the
sleeve down over the piston assembly as shown in Figure 8.
5. While still holding the sleeve, slide it up over the diaphragm
and, using your thumb & index finger, position the bead of
the diaphragm so that it wraps over the outside of the rib on
the top of the sleeve so that the sleeve is held by the
diaphragm. Now place the piston assembly on a flat, firm
surface with diaphragm facing up as shown in Figure 9.
6. Cup your hand slightly to form an air trap and force the
sleeve down over the piston assembly with a rapid slap
(hard) on the open end of the diaphragm with your cupped
hand. The trapped air in the diaphragm will force the
diaphragm between the inside of the sleeve and the outside
of the piston. Ensure that the diaphragm is fully seated by
running the end of a dull “butter” knife in the formed
diaphragm. If diaphragm is wrinkled, repeat previous step.
7. Slide the piston assembly and sleeve into the relief valve
body with the hex head bolt entering the flanged end of the
body first. Slide the piston assembly in until the diaphragm
lip is smoothly seated in the machined groove in the
flanged end of the body. By running your index finger
around the outside of the diaphragm bead, you will ensure
it is seated smoothly.
8. Position the bottom flange cover on the bottom of the
relief valve body and secure by hand tightening the (4) bot-
tom bolts.
9. Now tighten the (4) bottom bolts to approximately 15 ft.-lbs.
with a
5
/
16
" socket or open-end wrench.
10. Reattach the relief valve hose to the elbow in the bottom
flange cover.
Relief Valve Service Instructions
Parts Table #2
Item #
Part Description
Qty
Ames Part No.
21.
Relief Valve Body
1
7013337
22.*
Rubber Shut-Off Disc.
1
7013330
23.*
Piston Diaphragm Assembly
1
7013352
24.
Hex Head Bolt
1
7013326
25.
Disc. Retainer
1
7013328
26.
Sleeve
1
7013340
27.
Bottom Bolt
1
7012545
28.
Bottom Flange (w/St. Elbow)
1
7013339
29.
Elbow St 90 3/8
1
A403609
30.*
O-Ring Disk
2
7013327
31.
RV Spring
1
7013368
Not Shown - RV Rubber Kit (Includes * Items and Body O-Ring.)
7018897
Figure 9
Figure 6
Figure 7
Figure 8
Relief Valve
31
21
22
24
30
25
26
28
29
23
27
