Flomatic DCVE Installation Manual

Double Check Valve Assembly Backflow Preventer

Model DCVE - Sizes 3/4" - 2"

Installation, Testing & Maintenance Manual

Basic Installation Instructions

CAUTION: lnstallation of Double
Check Valves must be performed
by qualified, licensed person­nel. Faulty installation could
result in an improperly func­tioning device.

The installer should be sure the
proper device has been selected
for the particular installation.

FLOMATIC Model DCV Double
Check Valves are for use on
potable water lines where a health
hazard would not exist in the event
of a backflow situation.

Proper performance is dependent
upon following these installation
instructions and prevailing
governmental and industry stan­dards and codes. Failure to do so,
according to FLOMATICS Lim­ited Warranty "releases FLO­MATIC 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 arrestors and/or pressure
relief valves should be installed
downstream of the device.

1. Before installing a Model DCV
Double Check Valve, flush the
lines thoroughly to remove all
debris, chips and other foreign
matter. If required a strainer
should be placed upstream of the
Double Check Valve. CAUTION:

Do not use a strainer in seldom
used emergency water lines such
as fire lines.

2. Provide adequate space around
the installed unit so that the test
cocks will be accessible for testing
and servicing.

3. Always consult local codes for
installation methods, approvals and
guidelines.

Outdoor Installation

Model DCV Double Check Valve
may be installed outdoors only if the
device is protected against any freez­ing conditions. Exposure to freezing
conditions will result in improper
function or damage to the device.
The installation location must be kept
above 32oF. All the basic installation
instructions apply.

Indoor Installation

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

HIGH QUALITY VALVES BUILT TO LAST...

Parallel Installation
Where uninterrupted service from
a single meter connection must be
maintained, two or more Double
Check Valves may be connected in
parallel. All the basic installation
instructions apply to a 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
DCV unit has been completed,
place the unit in service as
follows:

1.Start with both shut-off valves
closed. Slowly open the inlet shut­off valve until the backflow
preventer is completely pressurized.

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

3. Slowly open the downstream
shut-off valve. The Model DCV
Double Check Valve is now in ser­vice.

4. After the backflow preventer
has been properly installed, test
the device (see Test Procedures).
If the device fails the test, remove
the first and second check valves
and thoroughly flush the device.
Clean rubber seats of all debris and
place unit back in service.

MAINTENANCE INSTRUCTIONS

1.GENERAL
A. Clean all parts thoroughly with water
after disassembly.
B. Carefully inspect silicone discs,and
o-rings for damage.
C. Test unit after reassembly for proper
operation.

2. SERVICING CHECK VALVES
A. Close inlet and outlet shut-off valves.
B. Open No. 2, 3, and 4 test cocks to
release pressure from valve.
C. Remove the cover bolts valve cover.
D. Remove check valve spring pin and
check valve assembly.
E. Inspect check valve seat and o-ring
for debris and damage.
F. To remove silicone disc, unscrew
check valve stem from disc holder.
G. Remove disc retainer and disc from
the discholder and inspect for cuts or
embedded debris.
H. The silicone disc may be inverted if
the reverse side is undamaged.

I. Inspect the valve cavity and seat area
for damage and debris.
J. Reverse the above procedures to rein­stall the check valve assemblies. NOTE:
Check valves can only be installed in
one configuration, they are not revers­ible.

TEST PROCEDURES

EQUIPMENT REQUIRED:
Bourdon Tube or Duplex gage
TEST #1
PURPOSE: Test No. 1 check valve for
tightness against reverse flow.
REQUIREMENT: The valve must close
tight against reverse flow under all pres­sure differentials.

1. Bleed water through all four test cocks
to eliminate foreign matter.

2. Install appropriate fittings.

3. Connect the high side hose to test
cock #2 and connect the low side hose
to test cock #3. Connections must be
drip tight!

4. Open test cocks #2 and #3, then bleed
hoses, making sure to bleed the low side
last.

5. Close #2 shut-off valve; then close #1
shut-off valve.

6. By means of the high side needle valve
lower the pressure at test cock #2 about
2 psi below the pressure at test cock #3.
If this small difference can be maintained
then check valve #1 is reported as "
tight".

TEST #2
PURPOSE: To test No. 2 check valve for
tightness against reverse flow.
REQUIREMENT: The check valve shall
be tight against reverse flow under all
pressure differentials.

1. Connect the high side hose to test
cock #3 and connect the low side hose
to test cock #4. Connections must be
drip tight.

2. Repeat steps 4 thru 6 in Test #1 above.

3. Check Valve No. 2 is considered
"tight" if the pressure differential is
maintained.

FIG. 2 Testing schematic for

Double Check Valve assemblies

FIG. 1: Installation schematic for

Double Check Valve assembly.

15 PRUYNS ISLAND

800-833-2040 * 518-761-9797 * Fax: [phone]

Valveactive Fax [phone] Outside U.S. 518-761-9799

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GLENS FALLS, NY 12801

YBFOMD
REV. 6/03