Relay Module 120V Microprocessor-Based Flame Safeguard for On-Off Burners
The Honeywell RM7890A2056 is a microprocessor-based primary burner control designed for automatically fired gas, oil, or combination fuel burners. It delivers safe, reliable sequencing of burner startup, flame supervision, and system shutdown. This model is suitable for on-off burner applications where consistent flame monitoring, prepurge functionality, and selectable safety interlocks are required.
Technical Specifications
- Model: RM7890A2056
- Series: RM7800
- Product Type: Primary Burner Control
- Voltage: 120V AC (+10%, -15%)
- Frequency: 50/60 Hz (±10%)
- Application: On-Off Burner Systems
- Pilot Type: Intermittent
- Flame Establishing Period – Pilot: 4 or 10 seconds
- Flame Establishing Period – Main: Intermittent
- PrePurge: Configured using ST7800A Purge Timer Module
- Interlocks: Selectable
- Delayed Main Valve: No
- Airflow Switch Check: Included
- Mounting: Requires Q7800A or Q7800B Subbase
- Flame Amplifier Compatibility: R7847, R7848, R7849, R7851, R7852, R7861, R7886
- LED Indicators: Five LEDs for sequence 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
- Shipping & Storage Temperature Range: -40°F to +140°F (-40°C to +60°C)
- Vibration Tolerance: 0.5 G
Key Features
- On-off burner control with integrated prepurge and flame supervision
- Modular design supports plug-in flame amplifiers for UV, IR, or flame rod sensors
- Optional keyboard display for diagnostics and lockout history
- Nonvolatile memory retains operational data and lockout codes
- Selectable flame loss response: relight or lockout
- Optional remote reset and remote annunciation capability
- Fully compatible with Honeywell’s RM7800 flame safeguard platform
Compatible Accessories
- Q7800A / Q7800B Universal Wiring Subbases
- ST7800A Purge Timer Card
- R7847, R7848, R7849, R7851, R7852, R7861, R7886 Amplifiers
- S7800A and 4-Line LCD Display Modules
- Honeywell flame rods and UV/IR scanners
Industry Applications
- Commercial boilers
- Industrial burners and furnaces
- Fuel-fired heating systems
- Thermal process equipment requiring fail-safe operation
Installation & Maintenance Notes
- Install with correct subbase and purge timer card
- Select the appropriate flame amplifier based on sensor type
- Monitor burner status using onboard LEDs or remote display
- Review and log lockout history via display module or control software
- Perform periodic flame signal testing during startup
This part is normally stock.
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