Relay Module Microprocessor-Based 120V Flame Safeguard with Prepurge
The Honeywell RM7890B2014 is a microprocessor-based primary burner control designed for use in automatically fired gas, oil, or combination fuel single-burner applications. It provides safe and reliable burner sequencing, flame supervision, and system diagnostics. This model supports prepurge functionality and is compatible with Honeywell’s modular RM7800 flame safeguard system, making it an ideal solution for commercial and industrial combustion systems.
Technical Specifications
- Model: RM7890B2014
- Series: RM7800
- Product Type: Primary Burner Control
- Power Supply: 120V AC (+10%, -15%), 50/60 Hz
- Application: On-Off Single Burner with Prepurge
- Pilot Type: Intermittent
- Flame Establishing Period – Pilot: 4 or 10 seconds
- Flame Establishing Period – Main: Intermittent
- PrePurge: Determined by ST7800A Purge Timer Card
- Interlocks: Selectable
- Delayed Main Valve: No
- Airflow Switch Check: Included
- Mounting: Requires Q7800A or Q7800B Universal Subbase
- Flame Amplifier Compatibility: R7847, R7848, R7849, R7851, R7852, R7861, R7886
- 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
- Shipping & Storage Temperature Range: -40°F to +140°F (-40°C to +60°C)
- Vibration Tolerance: 0.5 G
- Condition: New
Key Features
- Supports on-off burner operation with prepurge timing
- Interchangeable plug-in flame amplifiers for flexibility
- Five LED indicators for burner sequence and fault status
- Optional remote display, annunciation, and keyboard module
- Nonvolatile memory stores flame signal strength, runtime, and lockout history
- Optional remote reset and report generation capabilities
- Compatible with all standard Honeywell RM7800 system components
Compatible Accessories
- Q7800A / Q7800B Subbase
- ST7800A Purge Timer Card
- R7847, R7848, R7849, R7851, R7861, R7886 Flame Amplifiers
- S7800A or 4-Line LCD Keyboard Display Module
- Flame rods, UV and IR flame detectors
Industry Applications
- Industrial and commercial boilers
- Gas and oil-fired furnace control
- Thermal processing equipment
- Combustion systems requiring prepurge and safety monitoring
Installation & Maintenance Notes
- Install with appropriate subbase and purge timer
- Use flame amplifier matched to sensor and burner configuration
- Monitor LED indicators for operating status and lockouts
- Configure purge time via ST7800A module
- Periodically review stored history and lockout causes for proactive maintenance