Watts Series 800M4, LF800M4 Pressure Vacuum Breaker Assemblies

Important Safety Information

⚠️ WARNING: Read this Manual BEFORE using this equipment. Failure to read and follow all safety and use information can result in death, serious personal injury, property damage, or damage to the equipment. Keep this Manual for future reference.

⚠️ WARNING: Local building or plumbing codes may require modifications to the information provided. You are required to consult the local building and plumbing codes prior to installation. If the information provided here is not consistent with local building or plumbing codes, the local codes should be followed. This product must be installed by a licensed contractor in accordance with local codes and ordinances.

⚠️ WARNING: Need for Periodic Inspection/Maintenance: This product must be tested periodically in compliance with local codes, but at least once per year or more as service conditions warrant. All products must be retested once maintenance has been performed. Corrosive water conditions and/or unauthorized adjustments or repair could render the product ineffective for the service intended. Regular checking and cleaning of the product's internal and external components helps assure maximum life and proper product function.

⚠️ WARNING: Freeze sensor solely provides alerts about a possible freeze event and cannot prevent a freeze event from occurring. User action is required to prevent freeze conditions from causing product and/or property damage.

NOTICE: For Australia and New Zealand, line strainers should be installed between the upstream shutoff valve and the inlet of the backflow preventer. If installed on a fire sprinkler system, all mechanical checks, such as alarm checks and backflow preventers, should be flow tested and inspected internally in accordance with NFPA 13 and NFPA 25.

Testing and Service Parts

For field testing procedures, refer to Watts installation sheets IS-TK-DL, IS-TK-9A, IS-TK-99D, and IS-TK-99E at www.watts.com.

For other repair kits and service parts, refer to the Backflow Prevention Products Repair Kits & Service Parts price list PL-RP-BPD at www.watts.com.

For technical assistance, contact your local Watts representative.

Freeze Sensor Feature

Series 800M4 and LF800M4 antisiphon PVBs (FR and QT versions) include a freezer sensor to signal building/irrigation management systems when temperature nears the freezing point.

NOTICE: An add-on connection kit is required to activate the freeze sensor. Without the connection kit, the sensor is a passive component that has no communication with any other device. (The kit can also be used to retrofit existing installations. See “Add-on/Retrofit Sensor Connection Kit,” for ordering details.)

NOTICE: Use of the freeze sensor and activation kit with FZ models does not replace the need to comply with all required instructions, codes, and regulations related to installation, operation, and maintenance of the PVB assembly. Watts is not responsible for the failure of alerts due to connectivity or power issues.

Installation Guidelines

Pressure - Temperature

• Working Temperature: 33°F to 140°F (0.5°C to 60°C)
• Maximum Pressure: 150 psi (10.3 bar)
• Minimum Pressure: 15 psi (103 kPa)

Requirements

• Install 12" (30.5 cm) above the highest point of downstream piping. (See Figure 1.)
• Installation as stated above is essential for proper operation.
• Install bonnet side up and allow access for testing/service.
• Install where discharge or spillage is not objectionable.
• Do not undersize supply or oversize the valve relative to demand.
• Do not install where backpressure can occur.
• Protect from freezing. For freeze protection, specify Model 800M4FR or LF800M4FR. Or, consider the WattsBox insulated enclosure. For more information, download ES-WB at www.watts.com.
• Follow ASSE Standard 1020 that the atmospheric vent valve remains open until the valve body pressure exceeds 1 lb. Until this pressure is reached, some amount of spillage occurs at the atmospheric vent. To minimize this leakage on startup, close the downstream shutoff valve and open the inlet shutoff valve quickly.

Startup Procedure

1. Close shutoff No. 2 (outlet).
2. Open shutoff No. 1 (inlet) until water discharges from the bonnet then quickly open to pressurize the valve.
3. Open shutoff No. 2.

Freeze Protection

Use the following procedure to purge the PVB assembly with pressurized air. (See Figure 2.)

1. Close the main shutoff valve.
2. Open upstream drain, test cocks and isolation ball valves to depressurize line.
3. Purge with pressurized line.
4. Leave test cocks and isolation ball valve handles in a 45° angle to drain ball valves and prevent casting damage.

Typical Installation

The TWS hydrant is usually included in the PVB installation to provide outside access to a building water supply for startup, winterizing, and servicing of irrigation sprinkler systems. (See Figure 3.) The hydrant is connected to the PVB assembly and installed through the structure wall to connect to the water supply.

Diagram Descriptions:

Figure 1: Illustrates the required 12-inch minimum clearance above the highest point of downstream piping, showing a WattsBox enclosure and the PVB assembly.

Figure 2: Depicts the freeze protection procedure, showing a main shutoff valve, upstream drain, test cocks, and isolation ball valves.

Figure 3: Shows a typical installation with water supply, a Watts TWS hydrant connected to the PVB assembly, and piping to sprinklers.

Servicing and Maintenance

Internal parts can be removed, repaired, or inspected without removing the valve from the piping.

Routine Service

1. In cold climates, open the test cocks to drain if operated only seasonally.
2. Replace rubber goods every 5 years.

Vacuum Breaker Disassembly

1. Shut off the supply pressure and drain the valve.
2. Remove the two hood screws and the hood.
3. Place a wrench on the parallel flats of the bonnet and stem assembly. Turn counterclockwise and remove.
4. Remove the vent assembly.
5. Press down on the spring retainer and disengage it from the retaining lugs. Then turn 90 degrees and remove.
6. Remove the spring retainer and spring. Note that the large diameter of the spring is down on the guide assembly.
7. Remove the check disc holder and guide assembly.
8. Disassemble the check disc holder assembly.
9. Remove the seat (if required) by turning counterclockwise.

Vacuum Breaker Reassembly

Use the procedure above in reverse order to reassemble the vacuum breaker with new parts from the repair kit.

Add-on/Retrofit Sensor Connection Kit

This kit is for Building/Irrigation Management Systems.