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Watchdog III Flare Stack Monitoring System

Built rugged to last, the Watchdog III Flare Stack monitoring system reliably monitors flames from remote locations under difficult conditions such as dust, fog, heavy rain, snow and background sun rays. The ability to connect to an existing ignition system, and its ground mounted design, make it easy to install and service without flare shut down, saving valuable time and money.






  • System consists of a P222 signal processor and S256BE viewing head with a 50 foot interconnecting cable.
  • Not affected by the sun which allows viewing head to be located anywhere around the flare stack.
  • Easy to set up with multiple LED's and pushbuttons.
  • Lightweight and low power consumption.
  • No moving parts ensures reliability.
  • Easy installation and service with no plant shut down or flare interruption required.
  • S256BE ground mounted viewing head has a 1000 ft. line of sight range with 40 ft. diameter target (at 1,000 ft.).
  • P222 signal processor can be remotely mounted.
  • AC power: 85 to 264 VAC (300 mA maximum with viewing head connected), 7 or 440 Hz.
  • DC power: 22 to 26 VDC (300 mA maximum with viewing head connected).
  • Backup power: 22 to 24 VDC.
  • Signal processor ambient temperature: 32°F to 140°F (0°C to 60°C).
  • Viewing head ambient temperature: -40°F to 176°F (-40°C to 80°C).
  • Viewing head housing: NEMA 4X.
  • Analog flame signal: Scalable 0-20 mA or 4-20 mA output.
  • Two time delay relays: one 0-60 seconds (R1), one 0-3600 seconds (R2).
  • UV gain selection of 0-99.
QPS to CSA 22.2 (viewing head) for use in Class I Div 2 group C, D & T4

Remote flare flame monitoring ​



Part Number



Kit consisting of P222 signal processor, S256BE viewing head, 50-ft. ASY55XBE cable.


Replacement UV flare stack viewing head powered from P522 signal processor.


Replacement watchdog signal processor.

S256B Approximate Dimensions: Scope 20.25" (514 mm) x 3" diameter (76 mm)

P222 Approximate Dimensions: 7.25" Height (182 mm) x 4.25" Width (108 mm) X 6.4" Depth (163 mm)