Honeywell RM7840L1075 Integrated Burner Control 120V AC

The RM7840L1075 is a microprocessor-based integrated burner control designed for automatically fired gas, oil, or combination fuel single burner systems in commercial and industrial boiler, furnace, and burner applications. It operates on 120V AC, 50/60 Hz, drawing 10W, and functions across a -40°F to 140°F range. The control manages burner sequencing, flame supervision, system diagnostics, and safety interlocks, and communicates via Modbus. It is UL, CSA, FM, and IRI certified, single phase, hardwired, and non-programmable at the module level, requiring the S7800A1142 Keyboard Display Module for programming. This unit is an OEM replacement for the Honeywell R4126A1081 and is compatible only with Honeywell equipment. Recommended accessories include the S7800A Keyboard Display Module, ST7800A Purge Timer, and Flame Amplifier for full system operation. Installation requires a qualified professional given the safety-critical nature of burner sequencing and interlocks. Common failure symptoms this control addresses include burner lockout, flame failure, ignition failure, control malfunction, safety interlock faults, and diagnostic error codes.