WILKINS 350 - User Manual

Proposition 65 Warning This product contains chemicals known to the State of
California to cause cancer or birth defects or other reproductive harm.
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INSTALLATION INSTRUCTIONS
CAUTION: Installation of Backow Preventers must be performed by qualied, licensed
personnel. The installer should be sure the proper device has been selected for the
particular installation. Faulty installation could result in an improperly functioning device.
WILKINS Model 350 Double Check Valve assemblies are for use on potable water lines
where a health hazard does not exist in the event of a backow situation.
Damage to the device could result wherever water hammer and/or water thermal expan-
sion could create excessive line pressure. Where this could occur, shock arrestors, check
valves and/or pressure relief valves should be installed downstream of the device.
If installation is in a pit or vault, the Backow Preventer must never be submerged in
water because this could cause a cross-connection. Make sure that the pit or vault always
remains dry by providing ample drainage.
1. Before installing a Model 350 Backow Preventer, ush the line thoroughly to
remove all debris, chips and other foreign matter. If required, a strainer should be
placed upstream of the Backow Preventer. CAUTION: Do not use a strainer in
seldom used emergency waterlines such as re lines.
2. Provide adequate space around the installed unit so that the test cocks will be
accessible for testing and servicing.
3. Install valve at least 12 inches above surrounding ood level.
4. Always consult local codes for installation methods, approvals and guidance.
INDOOR INSTALLATION
Indoor installation is preferred in areas that
are subject to freezing conditions. All the
basic installation instructions apply to such
installations.
OUTDOOR INSTALLATION
The Model 350 Backow Preventer may
be installed outdoors only if the device
is protected against freezing conditions.
Exposure to freezing conditions will result
in improper function or damage to the
device. The installation location must be
kept above 32°F. All the basic installation
instructions apply.
PLACING THE DEVICE IN SERVICE
1. Start with both shut-off valves closed.
Slowly open the inlet shut-off valve until the
backow preventer is completely pressur-
ized.
2. When the unit has been pressurized,
vent any trapped air by slightly opening
each of the four test cocks.
3. Slowly open the downstream shut-off
valve. The Model 350 Double Check Valve
assembly is now in service.
4. After the Model 350 has been properly
installed, test the device (see “TEST PRO-
CEDURES”). If the device fails the test,
remove the rst and second check valves
and thoroughly ush the device. Clean rub-
ber and seats of all debris and place unit
back in service.
VERTICAL INSTALLATION
Vertical installation is acceptable in ap-
plications where inlet and outlet piping
are flowing vertically upwards. All the
basic installation instructions apply to such
installations. Consult factory for approval
status.
 Installation  Testing  Maintenance Instructions
(Patent No. 5,913,331)
Model 350, 350A, 350ADA & 350DA
Double Check Valve Assembly (8”, 10” & 12”) and
Double Check Valve Detector Assembly (8”, 10” & 12”)
DIRECTION OF FLOW
12" MIN.
30" MAX.
DIRECTION OF FLOW

Summary

Installation Instructions

General Installation Guidelines

Covers safety, line preparation, installation space, flood level, and local code adherence for proper setup.

Placing the Device in Service

Service Procedure Steps

Details on closing valves, opening inlet, venting trapped air, opening downstream valve, and post-installation testing.

Installation Location Considerations

Outdoor Installation

Guidelines for outdoor installation, emphasizing protection against freezing conditions for proper function.

Indoor Installation

Preferred installation method for areas prone to freezing conditions, adhering to basic installation instructions.

Vertical Installation

Acceptable for applications with vertical upward flow piping; consult factory for approval status.

Testing Procedures

Test No. 1: Check Valve #1 Tightness

Requirement and procedure for testing the tightness of the first check valve using a differential pressure gauge.

Test No. 2: Check Valve #2 Tightness

Requirement and procedure for testing the tightness of the second check valve using a differential pressure gauge.

Maintenance Instructions

General Maintenance

Includes cleaning parts, inspecting seals, and testing unit operation after disassembly and reassembly.

Servicing Check Valves

Detailed steps for disassembling, inspecting, and reassembling check valve assemblies, including part replacement.

Troubleshooting, Performance & Specifications

Troubleshooting Common Issues

Identifies common problems like leaking valves or low flow, listing possible causes and corrective actions.

Performance Characteristics

Graphs illustrating pressure loss versus flow rates for various Model 350 series configurations.

Technical Specifications

Details maximum working pressure, temperature limits, hydrostatic test pressure, and end connection types.

WILKINS 350 Specifications

General

Brand	WILKINS
Model	350
Category	Control Unit
Language	English