Reliable DDX, Instructions For Installation, Operation And Maintenance

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2.
General
The Reliable Model DDX Type D Double Interlock Preac-
tion system is designed for water sensitive areas that require
protection from inadvertent water flow into the sprinkler sys-
tem piping, but where a mechanical backup for the electric
release is not required. Typical applications for this type of
system are libraries and computer server rooms.
To release the valve and flow water into a Type D Double
Interlock Preaction System, two events must take place: a
fire detection device must operate, and the low pressure
switch must be operated by the loss of system air or nitro-
gen pressure due to sprinkler operation (see note 1 below).
These two signals must coexist at the releasing control
panel, which only then will energize the normally closed so-
lenoid valve (175 psi (12.1 bar) or 300 psi (20.7 bar) rated),
causing the water flow into the system.
These systems utilize fire detection devices and system
air pressure as separate zones (inputs) to a cross-zoned re-
leasing control panel. The solenoid releasing valve remains
closed until energized by the releasing control panel. This
will occur only when both a fire detection device is operated
and the low air pressure switch has detected sufficient loss
of system air pressure generally resulting from the operation
of a fire sprinkler.
In the event that the system piping is ruptured, or a sprin-
kler is accidentally opened, the low air pressure switch will
operate and an alarm will sound. The Model DDX Deluge
Valve, however, will not release water since the solenoid
valve remains closed due since the detection system has
not activated.
Conversely, in the event of a false alarm from the detection
system, the Model DDX Deluge Valve will not release water
provided air pressure in the system is maintained and the
low pressue switch is not activated. The requirement for
both detector operation and loss of system pressure before
the Model DDX Type D Double Interlock Preaction system
releases water assures maximum protection against inad-
vertent water flow.
At the heart of the Reliable Type D Double Interlock Pre-
action System is the Model DDX Deluge Valve. This deluge
valve is a hydraulically operated, straight-through-design,
differential latching clapper-type (see Fig. 1). System main-
tenance is simplified since the deluge valve can be reset
extermally without removing the cover plate. This feature
provides a significant system-restoration time advantage.
The Model DDX Deluge Valve has an intermediate cham-
ber and thereby does not require an in-line air check valve.
Subsequently, the deluge valve only requires a single drain
connection.
The Reliable Model DDX Type D Double Interlock Preac-
tion System trim set provides all of the necessary equipment
for connections to the Model DDX Deluge Valve pushrod
chamber inlet and outlet ports, a 1¼” (30 mm) main drain
on 2” (50 mm), 2½” (65 mm), 76 mm and 3” (80 mm) valve
sizes or a 2” (50 mm) main drain on 4” (100 mm), 165 mm,
6” (150 mm) and 8” (200 mm) valve sizes, alarm devices, air
supply, and required pressure gauges. This trim set is avail-
able in individual (loose) parts, in time-saving, segmented
assembled kit forms or fully assembled to the Model DDX
Deluge Valve (with or without a control valve).
Listings & Approvals:
(Only when used with Reliable Trim Sets.)
1. Reliable’s Type D Double Interlock Preaction Systems
2” (50 mm), 2½” (65 mm), 76 mm and 3” (80 mm), 4”
(100 mm), 165 mm, 6” (150 mm) and 8” (200 mm) are
Factory Mutual Approved Refrigerated Area Sprinkler
Systems for use in refrigerated rooms or buildings. Re-
frigerated area sprinkler systems are FM Approved as
complete systems. Systems are FM Approved for use
with thermal detectors and Class A detector wiring only.
2. Factory Mutual Approved for applications where FM
Global Data Sheets allow the use of double-interlock
preaction systems.
3. Reliable’s Type D Double Interlock Preaction Systems
2” (50 mm), 2½” (65 mm), 76 mm, 3” (80 mm), 4” (100
mm), 165 mm, 6” (150 mm) and 8” (200 mm) are Un-
derwriters Laboratories, Inc. Listed and UL certified for
Canada (cULus) in the Special System Water Control
Valve-Double Interlock Type (VLJH) category.
Note: Wherever the word “air” is used in this bulletin as a
reference to the pneumatic pressure source it shall also
mean “air or nitrogen.”
System Operation
When set correctly for service, the Model DDX Deluge
Valve is hydraulically established to separate the supply
water from the sprinkler system piping. The Reliable Model
DDX Deluge Valve is shown in both closed and open po-
sitions in Fig. 1. In the closed position, the supply pres-
sure acts on the underside of the clapper and also on the
pushrod through the pushrod chamber inlet restriction. The
resultant force due to the supply pressure acting on the
pushrod is multiplied by the mechanical advantage of the
lever and is more than sufficient to hold the clapper closed
against normal supply pressure surges.
Whenever the detection system is activated and a low
system air pressure condition coexist, the solenoid valve
is energized open which vents the pushrod chamber to
atmosphere through the chamber outlet. Since the pres-
sure can not be replenished through the inlet restriction as
rapidly as it is vented, the pushrod chamber pressure falls
instantaneously. When the pushrod chamber pressure ap-
proaches approximately on-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.
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 sprinkler system piping. Water also flows through the
alarm outlet to the alarm devices.
Resetting the clapper of the Model DDX Deluge Valve is
accomplished using the convenient external reset knob on
the rear of the valve. The external reset feature of the Model
DDX Deluge Valve provides a means for simple, economi-
cal system testing, which is one essential facet of a good
maintenance program. The external reset feature does not,