• Keypad Entry system
  • Password protection to avoid unauthorized alteration of the user-set (programmed) parameters.
  • Eight character alpha-numeric display.
  • Front panel LED Status Indicator.
  • Adjustable Independent Flame Relay Pull-In and Drop-Out Thresholds.
  • Adjustable Flame Failure Response Time (FFRT) (1 to 6 secs.).
  • Adjustable Independent Flame Relay Delay On Time (0 to 10 secs.).
  • Capable of analyzing signals from two scanners.
  • One Form C SPDT Marginal Alarm relay.
  • One fused DPDT Form C Flame relay.
  • One 4 – 20mA analog output (used to measure flame signal—scalable).
  • Remote communications capability to a PLC. Consult factory for details.


The 25SU3-2100 is a Flame Safeguard Amplifier used to detect the presence or absence of a flame in a single or multi-burner environment.

The 25SU3-2100 also maximizes burner discrimination with its ability to accurately differentiate the pulse rates produced by the scanners.

The 25SU3-2100 has the capacity to receive pulse inputs from two flame scanners, “A” and “B,”either separately or in combination. In addition, the 25SU3-2100 has two logic programs available,called “Scanner Option 1” and “Scanner Option 2.” Within these two scanner options, the user may select different operating parameters, and select the scanner or scanners that will provide the pulse input for that option. Switching between “Scanner Option 1” and “Scanner Option 2” is accomplished by an external dry contact input to the amplifier.

The dynamic range for the 25SU3-2100 amplifier is 1900 pulses per second, which is consistent with the output range provided by Fireye scanners. The pulse rate output of each scanner can be checked by the user, thus facilitating the maintenance of each scanner.