sure falls instantaneously. When the pushrod chamber pressure
approaches approximately one-third of the supply pressure, the
upward force of the supply pressure acting beneath the clapper
over comes the lever-applied force thereby opening the clapper.
To fully operate (deliver water from) a Dry Pilot Line Single In-
terlock Preaction System, two independent events must coex-
ist. A dry pilot line sprinkler/detector must fuse along with a re
sprinkler on the system. Independent operation of either a de-
tector or re sprinkler will cause an alarm to annunciate, but will
not cause water discharge from the re sprinkler system piping.
When a re is detected, the Model LP Dry Pilot Line Actuator
vents the pushrod chamber to atmosphere through the cham-
ber outlet. Since the pressure cannot be replenished through
the inlet restriction as rapidly as it is vented, the pushrod cham-
ber pressure falls instantaneously.
When the pushrod chamber pressure approaches approxi-
mately one-third of the supply pressure, the upward force of
the supply pressure acting beneath the clapper overcomes the
lever-applied force thereby opening the clapper.
In all Reliable Single Interlock Preaction Systems, once the
clapper has opened, the lever acts as a latch, preventing the
clapper from returning to the closed position. Water from the
supply flows through the Deluge Valve into the system piping.
Water also flows through the alarm outlet to the alarm devices.
Resetting the clapper of the Model DDX Deluge Valve is ac-
complished using the convenient external reset knob on the rear
of the valve.
The external reset feature of the Model DDX Deluge Valve pro-
vides a means for simple, economical system testing, which is
one essential facet of a good maintenance program. The exter-
nal reset feature does not, however, eliminate another important
facet of good maintenance, namely, periodic cleaning and in-
spection of the internal valve parts.
A valve body drain is provided in the event that water builds
up due to condensate from the air supply system or water left
inside from system testing. After closing the main supply valve,
the condensate drain can be opened slightly until the water in-
side the valve body and the main pipe column has drained. See
the section titled “Draining Excess/Condensate Water From Sys-
tem” in this bulletin for the detailed procedure.
The Model B Manual Emergency Station is also included in all
Reliable Single Interlock Preaction System trim sets. It consists
of an aluminum nameplate mechanically attached to a ball valve.
The valve handle in its OFF position is guarded against acciden-
tal turning to the ON position (and system discharge) by a nylon
cable tie provided with each trim kit. The cable tie is inserted af-
ter the system has been restored for operation. The nylon cable
tie is designed to allow, in case of an emergency, forceful turning
of the valve handle to the ON position. As an alternative to the
Model B Hydraulic Manual Emergency Station, the Model A Hy-
draulic Manual Emergency Pull Box (see Reliable Bulletin 506) is
also available and can be provided as an option.
Whenever ambient temperature conditions are high, the water
temperature in the Model DDX Deluge Valve pushrod chamber
could possibly increase, thereby increasing the pressure in the
chamber to values exceeding the rated pressure of the system.
In an indoor installation where standard room temperatures are
exceeded, a pressure relief kit may be needed. Pressure relief
kit, P/N 6503050001, can be installed into the pushrod cham-
ber’s releasing line to limit the pressure to 250 psi (17.2 bar).
Reliable Model DDX Deluge Valve with associated Single In-
terlock Preaction Trims sizes 2” (50 mm), 2½” (65 mm), 76 mm,
3” (80 mm), 4” (100 mm), 165 mm, 6” (150 mm) and 8” (200
mm) are rated for use at a minimum water supply pressure of 20
psi (1.4 bar); and a maximum water supply pressure of 250 psi
(17.2 bar) for 2” (50mm), 2½” (65mm), 76mm, 3” (80mm) and
8” (200mm) valve sizes and 300 psi (20.7 bar) for 4” (100mm),
165mm and 6” (150mm) valve sizes. Water supplied to the inlet
of the valve and to the pushrod chamber must be maintained
between 40°F (4°C) and 140°F (60°C).
Pressurizing Line Connection
The water supply for the pushrod chamber must be provided
a dedicated connection to the water supply piping. Pressurizing
lines for multiple Model DDX Deluge Valve pushrod chambers
must never be manifolded together. Each Model DDX Deluge
Valve must have its own pushrod chamber pressurizing line
connection.
This connection must be made on the supply side of the water
supply control valve. This can be accomplished by:
• Using a tapped connection directly below or next to the
main water supply control valve using a welded outlet or
the appropriate mechanical ttings. A grooved-end outlet
coupling is one way to achieve this; or
• Using a water supply control valve that has an available
threaded (NPT) supply-side tap design to allow for a direct
water supply connection to the Model DDX Deluge Valve
pushrod chamber.
Caution: The Reliable DDX valve is designed with an inlet
restriction built into the pushrod chamber. It is important not
to introduce additional restrictions into the direct water supply
connection or the discharge from the pushrod chamber by in-
stalling additional valves or improperly installing the copper lines
used in the trim of the valve.
Hydrostatic Testing of DDX Valves and DDX
Systems
As required by NFPA 13, re sprinkler systems with working
pressures up to and including 150 psi are to be hydrostatically
tested at a water pressure of 200 psi. Fire sprinkler systems
with working pressures above 150 psi are required to be hydro-
statically tested at 50 psi above the system working pressure.
In addition to the hydrostatic tests described above, dry pipe
and double interlock preaction systems require an additional
low pressure air test.
In some cases, hydrostatic testing (in accordance with the
NFPA 13 requirements noted above) will result in pressures that
exceed the working pressure of the valve and trim kit for the
two-hour test period. The valve and applicable trim kit have
been tested, approved and listed under these conditions
and as such, hydrostatic testing in accordance with NFPA
13 is acceptable. In addition, the clapper can remain in
the closed position and the trim kit need not be isolated,
as each has been designed to withstand hydrostatic test-
ing as required by NFPA 13.
5.
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