OEM Carrier Direct Spark Ignition (DSI) Control Board LH33WP003 for Model PY1PNA042100ADBA

This factory OEM Direct Spark Ignition (DSI) control board is the exact replacement specified for the Carrier PY1PNA042100ADBA packaged rooftop unit. The DSI control board is the central command module of the heating system — it orchestrates spark ignition, gas valve activation, inducer and blower motor sequencing, flame sensing, and safety lockout. When this board fails, common symptoms include a complete no-heat condition, repeated ignition lockout faults, the system attempting to light then shutting off after a few seconds, or erratic blower behavior. Attempting to run a unit with a failed control board can mask cascading failures; always replace with a factory-matched OEM board.

• Part Number: LH33WP003 | Direct Spark Ignition (DSI) Integrated Control Board | Microprocessor-based design | Factory-matched to Carrier OEM specifications
• Key Functions: Controls spark ignition sequence, gas valve open/close timing, combustion blower and indoor fan motor staging, flame rod signal monitoring, and automatic safety lockout with LED fault-code diagnostics
• OEM vs Generic: This is the factory OEM board — engineered to Carrier's original design tolerances. Aftermarket alternatives may omit proprietary timing sequences or diagnostic LED logic, leading to nuisance lockouts or reduced system safety response times.
• Install Difficulty: 3/5 — Requires de-energizing the unit at the disconnect and verifying zero voltage before proceeding. Tools needed: 1/4" and 5/16" nut drivers, needle-nose pliers, smartphone (photograph all wiring harness connections before disconnection). Recommended for qualified HVAC technicians. Allow 30–60 minutes for a careful swap and functional test.
• Warranty: 1-year OEM manufacturer warranty. In stock — ships same business day from our warehouse.

Compatibility: Direct OEM replacement for Carrier model PY1PNA042100ADBA packaged rooftop units equipped with Direct Spark Ignition heating. Verify your existing board's part number (LH33WP003 or LH33WP003A) against your unit's data plate before ordering. Not sure it fits? Our HVAC parts specialists verify fitment before you order — just reach out.