Relay Module 120V Microprocessor-Based Flame Safeguard for On-Off Burner Applications

The Honeywell RM7890A2015 is a microprocessor-based primary burner control designed for use in automatically fired gas, oil, or combination fuel single-burner systems. This control module provides safe and reliable sequencing, flame monitoring, and system shutdown with built-in diagnostics and prepurge support. As part of the RM7800 Series, it features modular compatibility with Honeywell flame amplifiers and system accessories.

Technical Specifications

  • Model: RM7890A2015
  • Series: RM7800
  • Product Type: Primary Burner Control
  • Voltage: 120V AC (+10%, -15%)
  • Frequency: 50/60 Hz (±10%)
  • Application: On-Off Burner Control
  • Pilot Type: Intermittent
  • Flame Establishing Period – Pilot: 4 or 10 seconds
  • Flame Establishing Period – Main: Intermittent
  • PrePurge: Configured via ST7800A Purge Timer Module
  • Interlocks: Selectable
  • Delayed Main Valve: No
  • Airflow Switch Check: Included
  • Mounting: Q7800A or Q7800B Universal Subbase Required
  • Flame Amplifier Compatibility: R7847, R7848, R7849, R7851, R7852, R7861, R7886
  • LED Indicators: Five LEDs for system status and fault annunciation
  • Weight: 1 lb 15 oz (0.9 kg)
  • Dimensions (with Q7800A): 5″ W x 5″ H x 5-1/4″ D
  • Dimensions (with Q7800B): 5″ W x 5″ H x 6-3/32″ D
  • Temperature Range (Shipping/Storage): -40°F to +140°F (-40°C to +60°C)
  • Vibration Tolerance: 0.5 G
  • Condition: New

Key Features

  • Provides complete burner sequencing and flame safeguard functionality
  • Prepurge operation for enhanced system safety
  • Plug-in compatibility with Honeywell flame amplifiers (UV, IR, flame rod)
  • Blinking LED status and lockout indicators for simplified troubleshooting
  • Nonvolatile memory retains lockout history and runtime status after power loss
  • Supports optional remote annunciation, reset, and display modules
  • Designed for easy replacement and integration into burner management systems

Compatible Accessories

  • Q7800A or Q7800B Subbase
  • ST7800A Plug-in Purge Timer Card
  • R7847, R7848, R7849, R7851, R7852, R7861, R7886 Flame Amplifiers
  • S7800A Keyboard Display Module
  • Honeywell flame rods, UV/IR flame detectors

Industry Applications

  • Industrial and commercial boilers
  • Process heating equipment
  • Furnaces and ovens
  • Fuel-fired HVAC systems

Installation & Maintenance Notes

  • Mount with compatible subbase and purge timer module
  • Select appropriate amplifier based on burner type and sensor
  • Monitor system operation via onboard LEDs or remote display
  • Test flame signal strength during commissioning and routine checks
  • Use stored lockout history for preventive maintenance and diagnostics

 

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