3
PRESSURE VACUUM BREAKER
B. Model 765 – 1
1
/
2
" through 2" sizes
1. Disassembly
a.
Close outlet ball valve then close inlet ball valve. Bleed residual pres-
sure by opening #2 testcock.
b.
Remove the six bonnet bolts and lift the bonnet from valve body.
Remove poppet and remove seat disc.
c.
To replace poppet spring: unscrew nut, unscrew guide pin and
remove spring. Use caution to avoid damage to guide pin. Install
new spring and reassemble.
d. Remove the spring retaining web, spring and check assembly.
2. Check Valve Seal Replacement
a. Remove guide retaining nut and guide, lift seal from holder.
b.
Insert new seal, position guide in center of holder/seal and thread
nut to retain guide. Lightly tighten nut to hold the guide from rotat-
ing.
3. Assembly
a.
Position the check valve assembly, spring and retaining web into
valve body. Ensure the arms of the retaining web are aligned with
the guide and supports in the valve body.
b.
Roll rubber disc into recess on poppet and position poppet assembly
in the retaining web. Place the bonnet on the valve body. Ensure the
retaining web is properly supported by the three case bosses inside
the bonnet.
c.
Insert the bonnet bolts and tighten.
d.
Rapidly open inlet ball valve to minimize spillage in the air vent.
Slowly open outlet ball valve.
e.
Test unit to ensure proper operation.
Pressure Vacuum Breaker – Model 765
"ONNET
!SSEMBLY
0OPPET
!SSEMBLY
/RING
3PRING
%RING
7ASHER
3TEM
(OLDER
$ISC
'UIDE
3CREW
2UBBER$ISC
0OPPET
2ETAINER
3PRING
#HECK
!SSEMBLY
#ANOPY
"ONNET
"ALL6ALVE
)LLUSTRATIONSHOWNISFORSIZES
THROUGH
ONLY
"ONNETANDBOLTFOR
ANDNOTSHOWN
#/--%2#)!,0!243
4EST#OCK
.UT
"OLT
.OTSHOWNUSEDFOR
n
Fig.
Description Quantity
765 765 765 765 765 765
No.
1
/
2
"
3
/
4
" 1" 1
1
/
4
" 1
1
/
2
" 2"
1
Nut
523-533-00 523-533-00 523-543-00 523-543-00 523-543-00 523-543-00
2
Canopy
300-092 300-093 300-089 300-089 300-083 300-083
4 Bolt 6 - - - -
1024564
1024564
6
O-Ring
1101068 1101068 398-140-72 398-140-72 398-247-72 398-247-72
7
Spring - - - -
630-096
630-096
10
Stem - - - -
200-767
200-767
13
Retainer
300-096 300-096 300-088 300-088
-
-
14
Spring
630-108 630-108 630-106 630-106 630-063 630-063
20
Test
Cock
2
781-074 781-074 781-075 781-075 781-075 781-075
22
Ball
Valve
2
781-047 781-048 781-049 781-050 781-051 781-052
Part Kits
Rubber Parts Kit (6, 11, 16)
905-020
905-020
905-021
905-021
905-022
905-022
Bonnet
Assembly
(5-10)
905-047
905-047
905-048
(2)
905-048
(2)
- -
Bonnet/Kit
(3,
5-10)
- - - -
901-857
901-857
Poppet
Assembly
(11,12)
905-049 905-049 905-050 905-050 901-860 901-860
Check
Assembly
(15-18)
905-051 905-051 905-052 905-052
-
-
Check Repair Kit (6, 13, 15-18)
-
-
-
-
905-070
905-070
Bonnet/Poppet Kit (5-12)
905-211
905-211
905-212
(2)
905-212
(2)
- -
(2) Kit includes parts to retrofi t older style units
b.
When installing the retaining bracket, ensure the spring is centered
around the base of the bracket.
c.
Roll rubber disc into recess on poppet and position the poppet
assembly in the valve body.
d.
To ease assembly of the bonnet into the valve body, apply a thin
coating of Vasoline on the o-ring.
DO NOT USE ANY OTHER
LUBRICANT.
e.
Ensure the guide pin of the bonnet correctly enters the hole in the
poppet.
f.
Thread the bonnet into the valve body by hand until the bonnet
flange bottoms on top surface of valve body.
DO NOT OVER-
TIGHTEN.
g.
Tighten canopy nut only until canopy cannot turn freely.
h.
Rapidly open inlet ball valve to minimize spillage through the air
vent. Slowly open outlet ball valve.
IOM-F-765.indd 3
8/11/08 2:56:42 PM
