624754R Nordyne Control Board Description The 624754R is the OEM microprocessor control board for Nordyne/Coleman gas furnaces and packaged heat pump systems. It orchestrates ignition sequencing, inducer control, gas valve operation, blower staging, safety interlocks, and fault diagnostics. An onboard LED communicates multi-flash fault codes for rapid troubleshooting. Key Specifications Specification Details Part Number 624754R Dimensions (L×W×H) 5.5 in × 3.15 in × 3.05 in Weight 0.52 lb (235 g) Control Voltage 24 VAC Connectors X1 (line/transformer), X2 (safeties), X3 (gas/ignitor/flame sense) Diagnostic LED Multi-flash fault-code indicator PCB Protection Conformal coating, corrosion-resistant terminals Compatibility This board supersedes original part 624754 and fits a broad range of Nordyne/Coleman equipment: Original Part No. Replacement Typical Applications 624754 624754R M4, M6, M7 gas furnaces (downflow/upflow) 624754 624754R DD, Q5RE, PCM packaged heat pumps Always verify your furnace or heat pump’s data plate and control harness configuration before ordering. Installation Tips Power Down First Disconnect all electrical supply before servicing to prevent damage or injury. Document & Label Wiring Photograph harness connections at X1, X2, and X3 before removal; relabel wires to ensure accurate reassembly. Mount Securely Use OEM standoffs; avoid over-torquing screws to prevent PCB stress or warping. Verify 24 VAC Measure voltage at the board’s X1 terminals; confirm ~24 VAC before connecting safety and gas circuits. Commissioning After restoration of power, observe LED flash patterns. Refer to the fault-code chart to clear any pre-existing errors. Cross-Reference & Resources OEM Replacement Mapping: 624754 → 624754R LED Fault-Code Lookup Chart for Nordyne Control Boards Wiring-Diagram Overlay with Connector Pin-outs (X1, X2, X3) Troubleshooting Flowchart: “No Ignition” → “Lockout Reset Procedure”
