Technical data

1.5.1 Reliable Model EX Dry System
The Reliable Model EX Dry system utilizes a dry pilot actuator directly mounted to the push-rod cham-
ber of a Model DDX deluge style valve. The dry pilot actuator can be held closed with pneumatic
system pressure much lower than that required for a conventional dry valve, and provides a separa-
tion between the hydraulically pressurized push-rod chamber and system pneumatic pressure. Loss
of pneumatic pressure in the system due to a sprinkler opening operates the dry pilot actuator which
vents to a drain, relieving hydraulic pressure from the push-rod chamber and allowing the Model EX
Dry Valve to open and flow water into the protected area. Alarm devices are activated upon the flow
of water into the sprinkler system piping. Pneumatic pressure can be provided from a tank-mounted
air compressor, plant air system, or nitrogen cylinders and must be regulated with a Reliable Model
A-2 Air Maintenance Device. Pneumatic pressure in the system is monitored by a pressure switch that
will provide indication of falling pressure due to leaks or failure of the compressed gas system. When
properly adjusted, the low pressure alarm will activate in advance of the dry pilot actuator, allowing the
owner an opportunity to correct problems with the pressurizing system before the dry valve opens. The
Reliable EX Dry System operates with pneumatic pressure between 8 and 40 PSI depending on the
pressure of the incoming water supply. Minimum pneumatic pressure when using the optional Model
B-1 accelerator and/or an EPS40-2 high/low pressure switch is 15 PSI.
Approvals and technical data for the Model EX Dry System can be found on Reliable Automatic Sprin-
kler Company Bulletins 358 and 359.
20.
Figure 19