SOCLA BA 4760 Anti-contamination Flanged Instruction Manual
- June 13, 2024
- SOCLA
Table of Contents
SOCLA BA 4760 Anti-contamination Flanged Instruction Manual
General
Designed to protect drinking water supply networks against the backflow of risk fluids up to category 4 according to NF EN1717.
The device is designed to prevent any backflow of polluted water into the drinking water supply network as a result of back pressure or back siphonage when the pressure upstream of the device is lower than the pressure downstream of it.
Fields of application
For systems liable to generate pollution risks:
- Sanitary networks: hospitals, laboratories, dialysis center’s, water treatment.
- Technical networks: heating, air conditioning, irrigation, water dispensers.
- Fire suppression systems: sprinklers, fire hoses.
- Professional networks: industrial facilities, surface treatment, chemical industry, agrifood.
- Temporary networks: water supply for trade fair stands, festivals, exhibitions.
Note: The applications also depend on legislation in the country of use. Please contact your national authorities for further information.
Technical specifications
- Type of fluid: clears water
- Operation: horizontal position
- DN 65 to 250 mm, Connections : drilled flanges
- Maximum operating pressure: 10 bar (1 MPa)
- Minimum inlet pressure: 1.5 bar (150 KPa)
- Maximum operating temperature: 65°C
Standards – Approval
Conforms to the following standards: EN1717, EN12729
Operating principle
The backflow preventer with verifiable reduced pressure zone includes:
- three zones: upstream, intermediate and downstream, each equipped with a pressure measuring device.
- two independent check valves, separating the intermediate zone.
- one automatic relief device connected to the intermediate zone to restore it to atmospheric pressure in the event of a failure.
This device is installed with a funnel with air gap.
Maintenance and accessibility of the internal components are facilitated by
the modular design of the replacement parts.
NORMAL FLOW CONDITIONS > FILLING / FLOW START
The two check valves are opened. The relief valve is closed (closing pressure
is lower than the upstream check valve opening pressure). Water is supplied to
the downstream chamber.
NO FLOW CONDITIONS > FLOW INTERRUPTION
The two check valves are closed. The relief valve is closed (because the
pressure required to close it is lower than the pressure required to open the
upstream check valve).
Malfunctions
There can be no inversion or fluctuations of pressure between the intermediate chamber and the circuit upstream of the backflow preventer. The construction of the device in accordance with standards requires the upstream pressure to remain 140 mbar higher than the pressure in the intermediate chamber at all times. This differential value controls the opening of the relief valve and the drainage of the backflow preventer. Backflow preventers with verifiable reduced pressure zones self-protect against their own malfunctions. The device is made safe in static pressure situations.
The following situations can arise:
UPSTREAM NEGATIVE PRESSURE / BACK-SIPHONAGE
The two check valves close. The relief valve opens and drains the intermediate
chamber.
NO FLOW WITH UPSTREAM VALVE DEFECTIVE
The upstream pressure increases the pressure in the intermediate chamber. The
relief valve opens and causes a continuous discharge
OVERPRESSURE WITH DOWNSTREAM VALVE SEALED
If the check valve is perfectly sealed, no malfunction will occur: the valve
remains closed.
OVERPRESSURE WITH DOWNSTREAM CHECK VALVE DEFECTIVE
The overpressure reaches the intermediate chamber causing the relief valve to
open and discharge into the sewage network.
Installation instructions
Installation
Before installing the BA backflow preventer, check that:
- The BA device must be easily accessible to allow inspection, maintenance and replacement of defective components
- Test points must be provided to enable the system to be tested without difficulty
- It must not be installed in areas subject to flooding
- It must be installed in a ventilated area (non-polluted atmosphere)
- The relief system must be capable of discharging the relief flow
- It must be protected against frost and extreme temperatures
- It must be installed horizontally with the relief port facing down
- The funnel, with air gap, must be connected to the relief network
- It can only be used for potential backflow not exceeding the relief capacity
The protection device must be installed by a qualified technician.
Commissioning
-
Flush and fully drain the upstream pipes before installing the BA protection device with its accessories.
-
Install the BA protection device with its accessories, in the direction of flow, as follows:
- Upstream: one type SOCLA or equivalent Butterfly valve,
- Between the upstream valve and the device: one type Socla Y333P or equivalent mesh strainer with drain cock.
- Downstream: one type Socla or equivalent Butterfly valve.
Adhere to the installation diagram below
The protection system must be assembled without forcing the inlet and outlet fittings
-
Fit the funnel on the BA protection device. It is designed to be connected to a pipe (e.g. PVC discharge pipe) with external diameter equal to the diameter shown (see øF)
Filling with water:
During filling with water:
- The upstream and downstream valves are closed,
- Open the upstream valve slowly, to bring the BA protection system up to pressure gradually,
- Open and close tap No. 1 and then taps 2 and 3 respectively to drain the BA protection device,
- Open the downstream valve slowly, to commission the BA protection system. Once the BA protection system has been commissioned, it:
- Ensures that the downstream water requirement is met
- Protects the upstream network against the risk of pollution
PRECAUTIONS:
- In the 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.
Set of protection BA4760
REF| DN| H| LT| ØF
mm| mm| mm| mm
149B3486| 65| 247,34| 740| 40
149B3097| 80| 270,51| 844| 40
149B3098| 100| 352,52| 986| 60
149B3400| 150| 405,06| 1224| 60
149B34011| 200| 485,7| 1485| 60
149B3402| 250| 485,7| 1631| 60
Nomenclature and sizing
Key
- Casing
- Outlet drain holder
- Hex head screw
- Union nut
- Draining valve seat
- Discharge valve spring
- Discharge valve
- Upstream check valve
- Retainer
- Draining valve stem
- Downstream check valve
- Membrane disc
- Safety seal
- Draining valve head
- Draining valve seat and cover
- Cover
- Test cock chain
- Protective head
- Eye bolt
- Screw
- Test cock M 1/2“ Gas
- Draining valve head seal
- Membrane
Testing kit
In accordance with national statutory regulations, BA backflow preventers must be regularly inspected (once a year in most countries) by an authorised maintenance technician.
BA backflow preventers must undergo compulsory annual testing using test equipment conforming to NF P43-018, such as Socla ref. 2234900M2 or equivalent.
This equipment must be checked at least once every two years.
Fitting / removal instructions
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).
Remove the check valves:
- Remove the retainers (9) using pliers.
- Remove the 1st check valve (8) : introduce a rod on the inlet side, and gently hit the check valve. Repeat the same operation for the 2nd check valve (9) (11).
Remove the relief valve seat:
The seat (5) of the draining valve is fitted in piston position on the bottom
of the casing (1), take it out:
- By hands through the internal side of the body if possible
- By pushing in direction of the body inside through the discharge hole using a screwdriver
Refitting instructions
CAUTION: during the assembly, Silicone grease will have to be applied on O-rings.
Replace the check valve
- Introduce the 1st check valve in its bore (8) (9). Then using a lever (bottom part placed in the relief valve bore) and a plastic wedge, push the subset to replace it.
- Important: take care that the relief valve seat is removed
- With the same method, mount the second check valve.
Replace the relief Valve
- Mount the relief valve seat in its bore . If necessary, push it using a plastic rod.
- Place the relief valve spring on the seat (5).
Before the final operation, carefully dry the surfaces (body – cover) in contact with the membrane. If the membrane is assembled for a second time, apply talcum powder on it.
On the working station, place the relief valve unit in the cover.
Take care of the membrane orientation
- Turn the subset and place the screws on the cover.
- Take the unit and carefully position the relief valve in the spring then in the seat.
IMPORTANT: angular movements have to be as smallest as possible.
Tight the screws to the following torques: DN65 : 80 mN – DN80 : 90 mN – DN100 : 130 mN
Replace 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.
- Then manually screw it until it reaches the draining valve (10).
Specification for DN200 and DN250:
- 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 (13). Reassembling the draining valve seat (5) and the spring (6).
Repair kits
Repair kits are available and make it possible to replace the specific defective part on the BA 4760 backflow preventer
DN| A| B| C| D| E| F| **Max. acceptable
torques ***
---|---|---|---|---|---|---|---
”| mm| mm| mm| mm| mm| mm| mm| Nm
2 1/2| 65| 185| 356| 155| 326| 63| 180| 40
3| 80| 200| 440| 173| 337| 63| 200| 40
4| 100| 220| 530| 201| 434| 80| 255| 40
6| 150| 285| 630| 230| 456| 80| 310| 110
8| 200| 340| 763| 272| 499| 80| 390| 300
10| 250| 395| 763| 272| 499| 80| 390| 300
- Maximum torque for tightening bolts of the backflow preventer cover
BA 4760
Repair kits for BA4760 backflow preventer
Modules/ kits| **** Items| DN| DN65 *| DN80| DN100| DN150| DN200|
DN250
Ref BA 4760| 149B3486| 149B3097| 149B3098| 149B3400| 149B3401| 149B3402
Serial number| “I 01000SI 000000”| “K 01000SK 000000”| “L 01000SL 000000”| “M
01000SM 000000”| “N 01000SN 000000”| “P 01000SP 000000”
A| 5-6-7-10-12-13-14-15-22| Relief valve moduleUpstream check valve and
retainer| 149B055379| 149B055380| 149B055381| 149B055382| 149B055383
B| 8-9| First check valve moduleDownstream check valve and retainer|
149B055301| 149B055370| 149B055371| 149B055372| 149B055373
C| 11-9| Second check valve moduleDraining valve assembly, head,
seat and cover, membrane, seals| 149B055374| 149B055375|
149B055376| 149B055377| 149B055378
D| 15-16-18-19-20-21| Complete cover moduleCover, draining valve
seat, cover, test cocks and screws| 149B055305| 149B055384|
149B055386| 149B055387| 149B055388
E| 2-3-4| Drain kitFunnel and screws| 149B055389| 149B055406
F| 18-21| Kit 3 Test cocks with caps| 149B055410
A+B+C| 5-6-7-8-9-10-11-12-13-14-15-22| Complete kit| 149B19|
149B20| 149B21| 149F017922| **** 149B25
- For former BA4760 DN65 Nr 149B3096, serie Nr J01000, please refer to DN 80.
Troubleshooting
| PROBLEM | POSSIBLE CAUSE | ACTION |
|---|
1. Rapid discharge of water through the relief valve followed by normal
operation| Pressure fluctuation in the upstream water supply network| None
2. Continuous discharge of water through the relief valve in the course of
normal operation| The relief valve is dirty or damaged| Clean or replace the
relief valve module
3. Continuous discharge of water through the relief valve in safe mode
(normal flow or no flow)| a. The upstream valve is dirty or damaged
b. The piston seal of the relief valve is dirty or damaged
c. The downstream valve is dirty or damaged| a. Clean or replace the
upstream valve
b. Clean or replace the relief valve module
c. Clean or replace the downstream valve
Guarantee
Watts products are thoroughly tested. The said guarantee covers solely
replacement or – at the full sole discretion of WATTS – repair, free of
charge, of those components of the goods supplied which in the sole view of
Watts present proven manufacturing defects. The period of limitation for
claims based on defects and defects in title is two years from delivery/the
passage of risk. This warranty excludes any damage due to normal product usage
or friction and does not include any modified or unauthorized repair for which
Watts will not accept any request for damage (either direct or indirect)
compensation (for full details see our website). All sales subject to the
Watts terms to be found on
www.wattsindustries.com
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