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4. Installation
4. Installation
4. Installation
4. Installation
4. Installation
Type BA backflow preventers must be installed horizontally.
Shutoff valves should be fitted on both sides. In addition, a
Abb.1
strainer (see section 11: Accessories) must be fitted
upstream of the back flow
preventer to protect against damage by
coarse dirt. The backflow preventer is installed without
bending or other stresses as follows:
1. Thoroughly flush system pipework (Fig. 1)
2. Ensure that connections on back flow preventer are
clean (Fig. 2).
3. Install backflow preventer as in Fig. 3,
observing section 4.1 and also the following
points:
Abb.2
Check flow direction arrow
Observe required clearances
Ensure good accessibility
Tighten backnuts to torque values given in table 1.
Connect discharge pipework close coupled and
without tight bends according toconnection
dimensions on table 2.
Install discharge pipework in such a way that the
discharge connection and the discharge valve can be
removed for inspection.
A straight calming section of five times the pipework
diameter is recommended downstream of the BA
backflow preventer
Table 1
Connection size
Tightening torque
(Nm)
Fig.3
A
C
G
D
B
Table 2
Connection size
A
B
C
D
E
F
G
Dimensions in mm
18
GB
½"
¾"
1"
1¼"
1½"
40
50
65
70
85
F
E
BA 294
BA 298
1
3
1
1
/
"
/
"
1''
1
/
'' 1
/
"
2"
65 FB
65
80
100
2
4
4
2
80
80
100
100
130
130
130
650
650
650
500
500
500
500
500
500
500
600
600
600
70
70
70
70
90
90
110
160
160
160
100
100
100
100
100
100
100
150
150
150
130
130
135
135
150
150
150
345
345
345
180
180
200
200
260
260
260
395
395
395
20
20
20
20
20
20
20
75
75
4.1 Guidelines for safe installation
2"
100
150
650
600
200
150
375
435
75
75
GB
Inlet pressure fluctuation, even without water draw off, can
lead to brief operation of the discharge valve. It is
therefore recommended that a pressure reducing valve be
fitted upstream of the backflow preventer.
The room where the backflow preventer is installed must
be accessible at all times and be free from frost. Good
ventilation is also necessary.
If the discharge pipework is also used for other appliances
or systems, then the pipework must be suitably sized to
allow for this.
No other unprotected potable water system may be
connected downstream of the back flow preventer.
Individual connections in the downstream system are not
protected against backflow or back syphonage. If
required, further protective measures can be installed as
necessary to protect individual parts of the system.
The backflow preventer must at all times be fully
accessible. Pressure gauges and controls may not be
added.
Where backflow preventers are installed care must be
taken that discharges are safely carried away by the
discharge pipework. Installation in ducts or areas where
there is a risk of flooding is not permissible. To facilitate
inspection and maintenance, a shutoff valve should be fitted
upstream and downstream of the backflow preventer. The
backflow preventer must be installed so that the discharge
valve is above the surrounding maximum water table.
The control of the discharge valve is fitted with suitable
safety equipment to ensure that in the event of failure the
discharge valve aperture remains fully open. If this
occurs, the following discharge flow rates can be
expected when the pressure in the middle chamber is 1.0
bar:
1
/
"
3
/
" 1'' 1
1
/
'' 1
1
/
" 2" 65FB 65 80 100 150
2
4
4
2
3
m
/h 12 12 12 12
12 12 12
35 35
35 35
19
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