Honeywell RM7800G1018 Relay Module

Configured for automatic burner sequencing and flame monitoring in industrial burner control systems, the Honeywell RM7800G1018 (RM7800G1018 Burner Control Units) provides direct physical/electrical execution. It manages pre-ignition, purging, low-fire proven interlocks, and running safety circuits through an integrated microprocessor-based relay architecture operating at 120 VAC.

Hardware Specifications

Process Control & Flame Safeguard Execution

The relay module coordinates burner startup interlocks using channel-to-channel isolation and structured timing sequences. It processes 4-20 mA HART loop protocol signals from external modulating controllers alongside discrete limits (Pre-ignition, Running, Low Fire), enforcing fail-safe lockout responses upon loss of flame signal or safety interlock trip.

Frequently Asked Questions

Q: Can the RM7800G1018 relay module be unplugged or mounted while the subbase is energized?

A: No. Removing or inserting the relay module into the subbase with 120 VAC line power applied can cause arcing across header terminals, internal component degradation, or accidental burner cycling. Always disconnect power to the burner control panel before servicing.

Q: What happens if a safety interlock breaks during the Running sequence?

A: A break in the Running interlock circuit immediately de-energizes the main fuel valve terminals and initiates a safety shutdown and lockout sequence. The status is recorded for local display on an attached Keyboard Display Module (KDM).

Field Installation Guidelines

1. Power Isolation: Turn off all line power (120 VAC) supplying the burner control system and subbase before installation or wiring adjustments.
2. Subbase Mounting: Plug the relay module straight onto the Q7800 wiring subbase, ensuring the terminal pins align completely before tightening the central retention screw.
3. Grounding & Shielding: Connect the Q7800 subbase ground lug directly to the control panel protective earth (PE) bus. Flame signal sensor leads and low-voltage control lines must use shielded twisted-pair cabling grounded at a single end.
4. Wiring Isolation: Route high-voltage ignition leads in a separate conduit away from low-voltage sensors and flame detector wiring to eliminate electromagnetic interference (EMI).