WILKINS 375XL, 375 Installation, Testing, Operation And Maintenance Manual

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FLOOR
DRAIN

INLET SHUT OFF

DIRECTION OF FLOW

12" MIN.

30” MAX.

AIR GAP

OPTIONAL
WATER
METER

175 PSIG 180ß F

3/4" 375 RP

ZURN

WILKINS

2” PIPE
(DRAIN LINE CAN
BE ANY STANDARD
PIPING MATERIAL)

PROTECTIVE

ENCLOSURE

Model 375, 375XL

Reduced Pressure Principle (3/4"-1")

 Installation  Testing  Maintenance 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 375 Reduced Pressure

Principle Backow Preventers are for use
on potable water lines where a health
hazard could exist if a backow situation
were to occur.

Proper performance is dependent upon
following these installation instructions
and prevailing governmental and industry
standards and codes. Failure to do so,
according to WILKINS Limited Warranty
"...releases WILKINS of any liability that it
might otherwise have with respect to that
device." Such failure could also result in
an improperly functioning device.

Damage to the device could result wherever
water hammer and/or water thermal expan­sion could create excessive line pressure.
Where this could occur, shock arresters
and/or pressure relief valves should be
installed downstream of the device.

1. Before installing a Model 375 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. WARNING: If installation of a Model

375 is in a building, a suitable drain ar­rangement MUST be provided to drain
off spillage from the relief valve. An air
gap at least two times the pipe diameter
must be provided between the relief valve
and the drain piping to prevent a cross­connection. Air Gap AG-11 not intended
to support weight of drain pipe.

CAUTION: Do not pipe the relief valve
solidly to a oor drain, sewer or sump.

CAUTION: An adequately sized drain is
required to prevent possible water dam­age due to relief valve discharge.

4. Install valve at least 12 inches above
surrounding ood level.

5. Always consult local codes for installa­tion methods, approvals and guidance.

OUTDOOR INSTALLATION

Model 375 Backow Preventers 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.

If installation is in a pit or vault, the Back­ow Preventer must never be submerged
in water because this will cause a cross­connection. Make sure that the pit or vault
always remains dry by providing ample
drainage.

INDOOR INSTALLATION

Indoor installation is preferred in areas
that are subject to freezing conditions. All
the basic installation instructions apply to
such installations.

PARALLEL INSTALLATION

Where uninterrupted service from a single
meter connection must be maintained, two
or more Backow Preventers may be con­nected in parallel. All the basic installation
instructions apply to parallel installation.
Be sure to allow adequate room between
the units for testing and repair.

PLACING THE DEVICE IN SERVICE

After the installation of a Model 375 has
been completed, place the unit in service
as follows:

375 REDUCED PRESSURE PRINCIPLE

1. Start with both shut-off valves closed.
Slowly open the inlet shut-off valve until the
backow preventer is completely pressur­ized. A brief discharge from the relief valve
may occur while the device is pressurizing.
The discharge should cease by the time the
shut-off valve is fully open. Device should
function properly. If the discharge does not
stop, refer to "MAINTENANCE INSTRUC­TIONS" for repair procedures.

2. After the device has been pressurized,
vent all trapped air from both check valves
by slightly opening each of the four test
cocks.

3. Slowly open the downstream shut-off
valve. The Model 375 Reduced Pressure
Principle Backow Preventer is now in
service.

4. If "spitting" or intermittent discharges
from the relief valve are noted, it could
be a result of pressure uctuation and/or
a water hammer condition in the system.
If such conditions exist, install a WILKINS
water pressure reducing valve, a WILKINS
Model 40XL check valve, or a WILKINS
Model 1250 water hammer shock arrest­ers in compliance with industry standards
as needed.

5. After the Model 375 has been prop­erly installed, test the device (see "TEST
PROCEDURES"). If the device fails the
test, remove the rst and second check
valves and thoroughly ush the device. If
the relief valve fails to operate properly,
inspect the sensing passage for clogging
(see "MAINTENANCE INSTRUCTIONS").
Clean rubber seals of all debris and place
unit back in service.

Proposition 65 Warning This product contains chemicals known to the State of California
to cause cancer or birth defects or other reproductive harm.

1

Testing Procedures

#1 TEST COCK

#2 TEST COCK

#3 TEST COCK

#4 TEST COCK

#1 SHUT-OFF
VALVE

VENT HOSE

LOW SIDE HOSE

HIGH SIDE HOSE

BY-PASS
VALVE "B"

BY-PASS
VALVE "C"

BY-PASS

VALVE "A"

#2 SHUT-OFF

VALVE

175 PSIG 180ß F

3/4" 375 RP

ZURN

WILKINS

a ® company

MODEL 375 REDUCED PRESSURE PRINCIPLE

ASSEMBLY

Equipment Required: Differential pressure gauge test kit.

TEST NO. 1

Purpose:
Test #2 check valve for tightness against reverse ow.
Requirement:
The valve must close tight against reverse ow under all pressure
differentials.

Procedure:

1. Attach the "HIGH" hose to test cock #2 and the "LOW"
hose to test cock #3.

2. Close #2 shut-off valve.

3. Open test cocks #2 and #3.

4. Open by-pass valves "C" and "A" and bleed to atmosphere
until all air is expelled.

5. Close by-pass valve "A". Open by-pass valve "B" and
bleed to atmosphere until all air is expelled. Close by-pass
valves "B" and "C".

6. Attach the "VENT" hose to test cock #4.

7. Slowly open by-pass valves "A" and "C" and keep by-pass
valve "B" closed.

8. Open test cock #4.

9. Indicated pressure differential will drop slightly. If pressure
differential does not continue to decrease, the #2 check
valve is considered tight.

TEST NO. 2

Purpose:
Test #1 check valve for tightness and record pressure drop across
#1 check valve.

Requirement:

The static pressure drop across the #1 check valve should be at
least 3.0 PSID greater than the relief valve opening point (TEST
NO. 3).

Procedure:

1. Close by-pass valve "A"

2. Close test cock #4, and disconnect "VENT" hose from test
cock #4.

3. Open by-pass valves "B" and "C" bleeding to atmosphere,
then close by-pass valve "B" restoring the system to
normal static condition.

4. Observe the pressure differential gauge and note this as
the #1 check valve psid.

Maintenance Instructions

All Model 375 Reduced Pressure Principle Backow Preventers
must be inspected and maintained by licensed personnel at least
once a year or more frequently as specied by local codes. Replace­ment of worn or damaged parts must only be made with genuine
"WILKINS" parts. The WILKINS Certicate of Limited Warranty
provides that failure to do so "...releases WILKINS of any liability
that it might otherwise have with respect to that device." Such
failure could also result in an improperly functioning device.

The Model 375 Reduced Pressure Principle Assemblies should
be thoroughly ushed after backow conditions occur to prevent
any type of corrosive deterioration to its components. Failure to

do so could result in malfunction of the device.

GENERAL MAINTENANCE

1. Clean all parts thoroughly with water after disassembly.

2

TEST NO. 3
Purpose:

To test operation of the differential relief valve.

Requirement:

The pressure differential relief valve must operate to maintain the
"ZONE" between the two check valves at least 2 PSID less than
the supply pressure.

Procedure:

1. Close by-pass valve "C" and open by-pass valve "A".

2. Open by-pass valve "B" very slowly until differential gauge
needle starts to drop. Hold the valve at this position and
observe the gauge reading at the moment the rst dis­ charge is noted from the relief valve. Record this as the
opening differential pressure of the relief valve.

WARRANTY: WILKINS Valves are guaranteed against defects of
material or workmanship when used for the services recommended.
If in any recommended service, a defect develops due to material or
workmanship, and the device is returned, freight prepaid, to WILKINS
within 12 months from date of purchase, it will be repaired or replaced
free of charge. WILKINS liability shall be limited to our agreement to
repair or replace the valve only.

2. Carefully inspect rubber seal rings, diaphragms and o-rings
for damage.

3. Test unit after reassembly for proper operation (see "Testing
Procedures").

SERVICING CHECK VALVES

1. Close inlet and outlet shut-off valves.

2. Open No. 2, No. 3 and No. 4 test cocks to release pressure
from valve.

3. Unscrew clamp screws, and remove clamp.
(inserting screw in center hole can remove stuck clamp).
Slide sleeve toward inlet pipe. Slide valve body toward
inlet and lift upward.

4. Using nger or blunt object, push in outlet end of body,
both checks should slide out the body inlet. (A phillips
screw driver will work in a 3/4" valve. The closed ball
valve handle will work in a 1" valve).

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WILKINS, a ZURN company