Whenever a fire and a low system air pressure condi-
tion are detected, the energized solenoid valve vents the
push rod chamber to atmosphere through the chamber’s
outlet. Since the pressure cannot be replenished through
the inlet restriction as rapidly as it is vented, the push rod
chamber pressure falls instantaneously. When the push
rod chamber pressure approaches approximately
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.
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
Deluge Valve alarm outlet to the alarm devices.
After system shutdown, resetting the Model DDX De-
luge Valve is quite simple. Doing so only requires pushing
5.
in and turning the reset knob at the rear of the valve (see
Fig 1). The external reset feature of the Model DDX De-
luge Valve provides a means for simple, economical sys-
tem testing, which is one essential facet of a good
maintenance program. The external reset feature does
not, however, eliminate another important facet of good
maintenance, namely, periodic cleaning and inspection
of the internal valve parts.
In the event that water builds up inside the valve due to
condensate from the air supply system or water left inside
from valve system testing, a drain is available for venting.
After closing the main supply valve, a small valve over the
drain cup can be opened slightly until the water inside the
valve body and the main pipe column has drained. See
the section titled “Draining Excess/Condensate Water
From System” in this bulletin for the detailed procedure.
Fig. 3