Note: When the drain port piping is also used to discharge fl ows from other sources this capacity
shall be taken into account additionally to the fl ow rates of table A to defi ne the appropriate piping
size.
• Before putting the device into operation, the upstream piping and BA-device shall be de-aerated
through test cock 10, 11 and 12 (see drawing 1).
Testing
In compliance with national instructions a BA-unit shall be tested periodically, in most countries
on an annual basis. Watts Industries offers test kits with pressure gauge and hoses (reference:
catalogue "Maintenance kits").
The testing shall be confi rmed by means of the appropriate certifi cation.
Observations
Observation
1. Short-time discharge of water through
relief valve followed by normal operation.
2. At normal operation continuous water
discharge through relief valve.
3. In discharge mode continuous water
discharge through relief valve.
Maintenance instructions (see drawing 1)
Disassembly
• Remove cover (3) from main body (1) by unscrewing bolts (4).
• Remove retainer (5).
• Remove fi rst check valve module (6) with the use of a screwdriver as handle.
• Remove relief valve module (8) either by a M10 bolt or by pushing the module upwards with a fl at
tool through the air-gap (9).
• Remove second check valve module (7) with the use of a screwdriver as handle.
Note: disassembly of relief valve body (2) from the main body (1) is not foreseen.
Assembly
• Mount second check valve module (7) into its bore in main body (1).
• Mount the relief valve module (8) into its location in the relief valve body (2).
• Mount fi rst check valve module (6) into its bore in main body (1).
• Position the retainer (5) between fi rst & second check valve (6 & 7) and on top of the relief valve
module (8). Only one position is possible.
• Mount the cover (3) and tighten the bolts (4).
Material specifi cations
• Main body: DZR brass CW602N.
• Relief valve body: polymer PA (co-polyamide).
• First & second check valve module: polymer POM.
BACKFLOW PREVENTERS BA BM
Possible reason
Pressure fl uctuation in the water supply.
Relief valve polluted or damaged.
a. First check valve polluted or damaged.
b. Seal relief valve piston polluted or
damaged.
c. Second check valve polluted or damaged.
Action
None.
Cleaning or replacement of relief valve module.
a. Cleaning or replacement of fi rst check valve
module.
b. Cleaning or replacement of relief valve
module.
c. Cleaning or replacement of second check
valve module.
3