Flomatic RPZ Installation Manual

Reduced Pressure Principle Backflow Preventers

Model RPZ - Sizes 2-1/2" - 10"

Installation, Testing & Maintenance Manual

Basic Installation Instructions

CAUTION: Installation of

Backflow Preventers 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 RPZ
Reduced Pressure Principle
Backflow Preventers are for
use on potable water lines
where a health hazard could
exist if a backflow or back­siphonage 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 FLOMATIC'S
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
RPZ Backflow Preventer,
flush the lines thoroughly to
remove all debris, chips and
other foreign matter. If
required a strainer should be
placed upstream of the
Backflow Preventer.

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

2. The Model RPZ must be
installed in a horizontal
position to provide proper
operation of the relief valve.

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

4. If installation of a Model
RPZ unit is in a building,
provide a suitable drain
arrangement to drain off
spillage from the relief valve.
An air gap of at least two
times the pipe diameter must
be provided between the
relief valve and the drain
piping to prevent a cross
connection.

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

5. Install valve at least 12
inches above surrounding
flood level.

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

Outdoor Installation
Models RPZ Backflow

Preventers 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 32o F. All the
basic installation instructions
apply.

If installation is in a pit or
vault, the backflow 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.

Indoor Installations
Indoor installation is

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

Parallel Installations
Where uninterrupted service

from a single meter
connection must be
maintained, two or more
Backflow Preventers may be
connected in parallel.

All the basic installation
instructions apply to a
parallel in- stallation. Be
sure to allow adequate room
between the units for testing
and repair.

Placing the Device in
Service

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

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

2. 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.

3. If the discharge does not
stop, refer to "Maintenance
Instructions" for Repair
Procedures.

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

5. Slowly open the
downstream shut off valve.
The Model RPZ Reduced
Pressure Principle Backflow
Preventer is now in service.

6. If ‘spitting’ or intermittent
discharges from the relief
valve are noted, ‘spitting’
(drainage) from the relief
valve could be a result of
pressure fluctuations and/or
water hammer condition in
the system. If such condition
exists, install water pressure
reducing valves or water
hammer shock arrestors in
compliance with industry
standards as needed.

7. 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. If the relief valve
fails to operate properly,
inspect the sensing passage
for clogging (also see
maintenance instructions).
Clean rubber seats of all
debris and place unit back in
service.

Test Procedures and Maintenance Instructions

Maintenance Instructions

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

2. SERVICING CHECK
VALVES
A. Close inlet and outlet shut­off valves.
B. Open # 2, 3 and 4 test
cocks to release pressure
from valve.
C. Remove the bolts from the
relief valve cover.

CAUTION: COVER IS
SPRING LOADED.

To avoid injury, hold cover
down firmly with one hand
while loosening bolts.
D. Remove relief valve cover
and assembly.
E. Remove the check valve
spring clips.
F. Remove the 1st check
valve assembly.
G. Remove the 2nd check
valve assembly.

DO NOT REMOVE THE
SPRING RETAINER FROM
THE STEM ASSEMBLY.
Remove the disc holder from
the stem assembly.

H. Inspect check valve seat
and o-ring for debris and
damage.
I. To remove silicone disc,
unscrew check valve stem
from disc holder.
J. Remove disc retainer and
disc from the disc holder and
inspect for cuts or embedded
debris.
K. The silicone disc may be
inverted if the reverse side is
undamaged.
L. Inspect the valve cavity
and seat area for damage
and debris.
M. Reverse the above
procedures to reinstall the
check valve assemblies.
NOTE: Check valves can
only be installed in one
configuration, they are not
reversible.

3. SERVICING RELIEF
VALVE
A. Remove relief valve cover
bolts.

SPRING RETAINER

SPRING

O-RING

SEAT RING

CAUTION: COVER IS
SPRING LOADED.

Hold cover firmly with one
hand while removing bolts.
B. Remove cover, piston
assembly and spring.
C. Inspect o-ring and
diaphragm for cuts or
embedded debris.
D. Remove diaphragm by
unscrewing the relief valve
piston from the stem.
E. Inspect relief valve disc for
damage and debris.
F. To remove disc, unscrew
disc retainer from relief valve
stem.

NOTE: Relief valve disc is
also reversible.
G. Remove stainless steel
relief valve seat and inspect
for damage and debris. Also
inspect seat o-ring for
damage.
H. Reverse the above
procedures to reinstall the
relief valve.

DO NOT DISASSEMBLE

STEM

DISC RETAINER

DISC

DISC HOLDER

Test Procedures

EQUIPMENT REQUIRED:
Differential Pressure Test
Gauge

TEST #1-Relief Valve
PURPOSE: Test operation of
pressure differential relief valve.

1. Open #4 test cock to
establish flow through the unit;
then flush water through test
cocks #1, #2, & #3, by opening
and closing each test cock one
at a time, to eliminate foreign
material. Be careful not to dump
the relief valve during this
process (open #2 test cock
slowly). Close test cock #4.

2. Install appropriate gauge
fittings.

3. Install hose from the high side
of the differential pressure
gauge to the #2 test cock.

4. Install hose from the low side
of the differential pressure
gauge to the #3 test cock.

5. Open test cock #3 slowly and
bleed all air from the hose and
gauge through the low side
bleed needle valve. Maintain
the low side bleed needle valve
in the open position while the
test cock #2 is opened slowly.
Open the high side bleed
needle valve to bleed the hose
and gauge. Close the high side
bleed needle valve; then close
the low side bleed needle valve
after the gauge has pinned at
the upper end of the scale.

6. Close #2 shut-off valve.

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7. Observe the apparent
pressure drop across the No. 1
check valve; during all
subsequent steps of this
procedure the differential gauge
is "on line" showing the
pressure drop across the No. 1
check valve.

8. Open the high side control
needle valve, and then open the
low side control needle valve
slightly to bypass water from the
#2 test cock to the #3 test cock.

9. Watch the pressure
differential drop slowly to the
relief valve opening point,
record this value.

10. Close the needle valves.
TEST #2
PURPOSE: Test No. 2 check

valve for tightness against
reverse flow.
REQUIREMENT: The valve
MUST close tight against
reverse flow under all pressure
differentials.

1. Maintain the No. 2 shut-off
valve in a closed position.

2. Vent all of the air through the
by-pass hose by opening both
the high side control needle
valve and the bypass needle
valve. Close the bypass needle
valve only.

3. Install the by-pass hose from
the gauge manifold to the #4
test cock, then open the #4 test
cock.

4. Bleed water from the "zone"
by opening the low side bleed
needle valve on the gauge in
order to re-establish the normal
reduced pressure within the
"zone". Once the gauge
reaches the high end of the
scale, close the low side bleed
needle valve.

5. Open the by-pass needle
valve. No. 2 check valve is
"closed tight" if the pressure
differential remains steady.

TEST #3
PURPOSE: Test pressure drop

across check valve No. 1.
REQUIREMENT: The pressure
drop across check valve #1
must be at least 3 PSI greater
than the point obtained in test
#1.

1. Bleed water from the "zone"
through the low side bleed
needle valve on the gauge until
the gauge reaches the high end
of the scale. Close the low side
bleed needle valve. After the
needle settles record the static
pressure drop across check
valve No. 1.

BUL921

REV 6/06