Honeywell RM7890A1056 Burner Control Modules

The Honeywell RM7890A1056 serves as the primary RM7890A1056 Relay Module utilized to execute on-off primary control and safety sequencing across 7800 SERIES automatically fired single-burner platforms. The unit mounts to a standard wiring subbase to directly actuate intermittent pilot ignition, monitor pre-ignition interlocks, manage selectable pilot flame establishing periods, and operate programmable Valve Proving Systems (VPS) for gas, oil, or combination fuel burner configurations.

Hardware Specifications

Process Control and DCS Interface Features

The module features dynamic channel-to-channel isolation between low-voltage micro-ampere flame sensor inputs and line-voltage heavy-duty relay outputs. Process parameters, system status, lockout diagnostics, and flame signal telemetry transfer across the serial ControlBus communication architecture, enabling seamless data integration into host DCS and PLC network architectures without degrading the safety loop isolation performance.

Frequently Asked Questions

Q: Does the RM7890A1056 require an external plug-in purge card for operation?

A: No, the RM7890A1056 operates as an on-off primary burner control without requiring an ST7800 purge card, but still requires a plug-in flame signal amplifier and Q7800 subbase.

Q: How is the Valve Proving System (VPS) feature configured on the RM7890A1056?

A: The integrated VPS function is programmed via an optional S7800 Keyboard Display Module connected directly to the front ControlBus port of the relay module.

Field Installation Guidelines

1. Lock out and isolate all 120 VAC incoming power feeds prior to seating or removing the module from the Q7800 wiring subbase.
2. Verify subbase card-edge slots are clean and correctly wired in compliance with local electrical safety standards.
3. Align the rear terminal block pins straight into the subbase socket and tighten the central captive retaining screws to ensure proper ground contact and vibration resistance.
4. Maintain a minimum clearance distance of 150 mm between low-voltage flame sensor lines, serial ControlBus cables, and high-voltage ignition leads.