120V Microprocessor-Based On-Off Primary Burner Sequencer
The Honeywell RM7850A2001 is a microprocessor-based primary burner control designed to manage safe operation and flame monitoring in on-off burner systems using gas, oil, or combination fuels. This control is part of the RM7800 Series and offers reliable sequencing, flame supervision, self-diagnostics, and system status indication. Its modular design allows for easy integration with various flame detection methods and burner configurations.
Technical Specifications
- Model: RM7850A2001
- 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 Plug-in Purge Timer Card
- Delayed Main Valve: No
- Airflow Switch Check: Included
- Interlocks: Selectable
- Mounting: Requires Q7800A or Q7800B Universal Subbase
- Flame Amplifier Compatibility: R7847, R7848, R7849, R7851, R7852, R7861, R7886
- LED Indicators: Five LED lights for burner status and fault annunciation
- Memory: Nonvolatile memory retains lockout history and sequence data after power loss
- 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: -40°F to +140°F (-40°C to +60°C)
- Vibration Tolerance: 0.5 G
- Condition: New
Key Features
- Microprocessor-based safety and sequencing for single-burner applications
- Compatible with Honeywell UV, IR, and flame rod amplifiers
- Supports plug-and-play modular components for flexible burner configurations
- Prepurge operation via external timer card for compliance and safety
- Blinking LEDs provide real-time sequence and lockout status
- Optional support for remote reset, annunciation, and keyboard display modules
- Lockout and runtime data retained after power interruption
Compatible Accessories
- Q7800A / Q7800B Subbase
- ST7800A Purge Timer Module
- R7847, R7848, R7849, R7851, R7852, R7861, R7886 Amplifiers
- S7800A or 4-Line LCD Keyboard Display Modules
- Flame rods and UV/IR flame detectors
Industry Applications
- Industrial furnaces and boilers
- Process heating systems
- Commercial burner control panels
- Fuel-fired HVAC equipment
Installation & Maintenance Notes
- Ensure subbase and purge timer are installed properly
- Match flame amplifier to burner and sensor type
- Test flame signal during commissioning for proper sensitivity
- Use display module for fault tracking and lockout diagnostics
- Perform periodic inspections of wiring, terminals, and grounding
This part is normally stock.
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