Pneumatic Time Delay Cabinet

The TOMCO2 Systems pneumatic time delay cabinet is a pneumatically operated assembly of a pressure gauge, supervisory pressure switches, dial timers, 24vdc solenoid and mechanical override all interconnected by tubing and mounted in a NEMA 12, 4 or 4x enclosure. Three 1/2” [12.7] NPT connections on the enclosure provide connections for the necessary external piping.

One time delay cabinet should be provided for each master/selector valve within the system and should be located at or near the valve being controlled. The emergency manual push-button located on the side of the cabinet should only be used in the event of failure to the automatic or normal manual actuation devices.

The actuation line from the timer cabinet up to and including the actuator is supervised at 10 psig. The circuit includes a 15 psig pressure relief valve to prevent over pressurization of the line if the pressure regulator fails. Upon loss of the supervisory pressure, a pressure switch sends a signal to the main control system.

The storage unit provides 100 psig of CO2 vapor pressure through a regulator for operation of the timer cabinet. When the solenoid or emergency manual operator are actuated, the CO2 vapor pressure will accomplish the following:

  1. Delay discharge for a pre-determined, adjustable time period.
  2. Immediately alert personnel of the pending CO2 discharge with a pneumatic operated siren that by-passes all time delays.
  3. Provide pneumatic pressure to open the master/selector valves to begin the discharge and then, after a predetermined time, vents the pneumatic pressure which will cause the valves to close.

The delay timer provides 3 to 60 seconds of pre-discharge time. The discharge timer causes the master/selector valves to remain open for predetermined discharge time adjustable between 18 seconds to
10 minutes. An optional timer is available for extended discharges up to 100 minutes.

Part Number:

  • NEMA 4x: 990400
  • NEMA 4: 990401
  • NEMA 12: 990402

Approval: FM Approvals

FM Approvals has not verified the NEMA rating of the enclosure.

pneumatic time delay cabinet 1

Front View

pneumatic time delay cabinet 2Left & Right Side View

pneumatic time delay cabinet 3


Top Plate Layout


pneumatic time delay cabinet 4

Wiring Schematic