Socla BA 4760 Manuel Technique page 7

DisMANTLiNG - EXCHANGiNG Of iNTERNAL pARTs
- REAssEMBLiNG
all components of the backflow preventer can be checked or
replaced on site without removing the entire device.
• stop the flow by closing the upstream and downstream
stop valves.
• Drain the backflow preventer by opening the upstream
test cock.
• Remove the screws (20) of the cover (16).
• Separate the cover (16) from the casing (1). If necessary,
in case the cover gets stuck, insert any cover screw (20)
into the additional hole of the cover until the cover is free.
• Take out the draining valve assembly A from the
casing (1).
CHANGiNG THE DRAiNiNG VALVE sEAT AND COVER (15)
• Use a claw if necessary to take out the draining valve
seat and cover.
• When reassembling, lubricate slightly the o'ring to ease
the insertion in the cover (16).
CHANGiNG THE DRAiNiNG VALVE HEAD sEAL (22)
• Use a screwdriver to take out the seal (22) without dama-
ging the draining valve head groove.
• When reassembling, lubricate sligthly the o'ring (15) to
ease the insertion.
CHANGiNG THE DRAiNiNG VALVE HEAD (14)
• Unscrew the draining valve head to change it.
• Then screw it until it reaches the membrane disc (12).
When reassembling, place the o'ring between the draining
valve head and the draining valve stem.
CHANGiNG THE DRAiNiNG VALVE (7)
• Unscrew the discharge valve to change it.
• Then manually screw it until it reaches the draining valve
(10).
CHANGiNG THE DRAiNiNG VALVE sEAT (5)
• The seat (5) of the draining valve is fitted in piston position
on the bottom of the casing (1).
• To remove it, just push the seat through the discharge
hole in direction of the casing inside. When reassembling,
lubricate sligthly the o'ring to ease the insertion.
CHANGiNG THE UpsTREAM VALVE (8) OR DOWNsTREAM
VALVE (11)
• We supply these two valves as tested units ; no spare parts
are available. When reassembling these valves, remove
the retainer with pliers (or screwdriver) then manually
remove the valves.
Specification for ND200 and 250 :
Dismantling of the upstream and downstream check valves : insert two
screws into the upstream and downstream threaded (M10) in order to
remove the upstream and downstream subset out of their own bore. Then
remove them from the body.
Reassembling of the new subset (upstream and downstream check valve)
: introduce the first subset in the body bore, then with a lever into the low
part of the body (draining valve seat removed), push the subset to replace
it. Remark : the upstream seat is equipped with an external notch with
must be placed in the low part of the body. Do not forget to replace the two
safety seals (9). Reassembling the draining valve seat (5) and the spring (6).
CHANGiNG THE OUTLET DRAiN HOLDER (2)
• The outlet drain holder is maintained on the casing by
bolts and nuts. When replacing it, remove the screws from a
groove on the casing.
GB
iNsTALLATiON spECifiCATiON
The correct installation requires :
- Upstream : stop valve + filter (with washing cock)
- Downstream : stop valve
THIs baCKFloW pREVEnTER musT bE mounTED In
HoRIZonTal posITIon.
Sufficient distance
to allow checking
pRECAUTiONs :
In case of an upstream diversion in the area right in front of
the backflow preventer, it is necessary to install a check valve
between the diversion and the backflow preventer.
always manipulate the upstream valve slowly to put the
backflow preventer under pressure gradually.
MAINTENANCE AND CONTROL kIT FOR
BACkFLOw PREvENTERS
In accordance with antipollution stan-
dard and hygiene regulations, BA back-
flow preventers must undergo an annual
performance check for which the user
is responsible. For this purpose
Socla proposes two kinds of
maintenance kits allowing these
periodic checks to be made.
HEADLOSS CHART
P
30
2
25
1.6
20 1.4
1.2
15
1
.8
.7
10
.6
8
.5
7
6
.4
5
.3
4
.25
3
.2
2
1 .1
Ceiling, vault, beam, shaft or any obstacles
Ground, floor, terrace, footbridge
Sewer
Drain
Gallery
DN
1 2 3 4 5 6 8 10 15 20 25 30 40 50 60 80
4 5 6 8 10 15 20 30 40 50 60 80
Gutter
Ref. : 1020
DEBIT M
100 200 300 400 600 1000
FLOW GA