Technical Overview
The Honeywell RM7890A1056 is a microprocessor-based primary burner control for automatically fired single-burner systems. This relay module handles gas, oil, or combination fuel applications with comprehensive flame supervision and safety shutdown functions. It includes pre-purge timing and can be set for intermittent or interrupted pilot duty. The module requires a Q7800 wiring subbase and a compatible plug-in flame amplifier for complete operation. Five LEDs on the front panel provide clear sequence information, and a non-volatile memory retains fault history even after a power loss. The system supports optional Modbus communication via the S7810M1003 module.
Technical Specifications
| Parameter | Specification |
|---|---|
| Manufacturer | Honeywell |
| Model Number | RM7890A1056 |
| Product Type | Primary Burner Control / Relay Module |
| Voltage | 120 Vac (+10/-15%), 50/60 Hz (±10%) |
| Power Dissipation | 10 W maximum |
| Maximum Connected Load | 2000 VA |
| Fuse Rating | 15 A maximum, Type SC Fast Blow |
| Pilot Type | Intermittent or interrupted (selectable) |
| Pilot Flame Establishing Period | 4 or 10 seconds (selectable) |
| Main Flame Establishing Period | 10 seconds |
| Pre-Purge | Programmable via ST7800A purge card |
| Post-Purge | 2 seconds (fixed) |
| Flame Failure Response Time | 0.8 to 3.0 seconds (depends on amplifier) |
| Operating Temperature | -40°C to +60°C |
| Storage Temperature | -40°C to +66°C |
| Humidity Rating | 85% RH continuous, noncondensing |
| Vibration | 0.5G continuous |
| Dimensions | 127 x 127 x 133 mm |
| Weight | 0.83 kg |
| Mounting Type | Panel mount with Q7800 subbase |
| Required Components | Q7800 subbase, R78XX amplifier, ST7800 purge timer |
| Approvals | UL, CSA, FM, CE (EN 298), SIL 3 capable |
| Country of Origin | USA |
Key Features
Microprocessor-Based Safety – The advanced processor delivers reliable burner sequencing and comprehensive flame supervision.
Non-Volatile Memory – The module retains lockout status, fault history, and cycle counts after complete power loss.
Selectable Pilot Duty – Users can choose intermittent or interrupted pilot operation, offering flexibility for various burner configurations.
Pre-Purge Timing – The programmable pre-purge ensures safe chamber clearing before ignition sequences begin.
Universal Amplifier Compatibility – The module works with R7847, R7848, R7849, R7851, R7852, R7861, and R7886 amplifiers.
Optional Modbus Interface – The S7810M1003 module enables remote monitoring and configuration capabilities.
Diagnostic LEDs – Five front-panel indicators provide real-time sequence and fault status information.
Required Components
The Honeywell RM7890A1056 requires several separately purchased components: a Q7800A or Q7800B Universal Wiring Subbase, a compatible plug-in flame signal amplifier, and an ST7800A Plug-in Purge Timer Card. The optional S7800 Keyboard Display Module provides advanced status indication and configuration capabilities.
Applications
This burner control excels in industrial combustion management for boilers, process furnaces, ovens, and heaters. It delivers reliable performance in power generation, chemical processing, and manufacturing environments where primary burner control is essential.
Details
| Weight | 0.2 kg |
|---|---|
| Dimensions | 85 × 65 × 30 mm |
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