Honeywell RM7890A1031 Relay Module

Configured for automatic burner sequence execution and primary flame supervision in 7800 SERIES combustion platforms, the Honeywell RM7890A1031 (RM7890A1031 Burner Control Unit) provides direct physical/electrical execution. It mounts directly to a Q7800 wiring subbase to supervise intermittent pilot ignition, extended pilot flame establishing sequences, safety interlock inputs, and main fuel valve circuit outputs across industrial single-burner installations.

Hardware Specifications

Process Control and DCS Interface Features

The module relies on channel-to-channel isolation to decouple low-voltage micro-ampere flame sensor inputs from 120 VAC output switching logic. Operating telemetry, sequence state timing, and real-time diagnostic lockout codes pass through the front-facing serial ControlBus port, enabling direct data integration into supervisory DCS networks and industrial PLCs without compromising safety circuit integrity or loop isolation.

Frequently Asked Questions

Q: What is the primary operational distinction of the RM7890A1031 compared to standard 7800 SERIES primary relay modules?

A: The RM7890A1031 features a fixed 30-second pilot flame establishing period to accommodate specialized industrial pilot burner ignition requirements.

Q: Is a plug-in purge timer card required to operate the RM7890A1031?

A: No, the RM7890A1031 functions as a non-purge primary control module, but it still requires a plug-in flame signal amplifier and a compatible Q7800 subbase for full system operation.

Field Installation Guidelines

1. Disconnect and isolate all line-voltage AC power feeds connected to the Q7800 subbase prior to installing or removing the module.
2. Check subbase terminal headers to ensure clean card-edge contacts and proper physical alignment.
3. Align the rear connector of the RM7890A1031 straight into the subbase socket and secure the captive retaining screws to prevent loose terminal connection under field vibration.
4. Maintain a physical separation of at least 150 mm between low-voltage flame signal lines, serial ControlBus wiring, and high-voltage ignition transformer leads.