OEM Carrier Direct Spark Ignition (DSI) Control Board LH33WP003 for Model PY3PPA036090AB

This is the factory OEM Direct Spark Ignition (DSI) control board for the Carrier PY3PPA036090AB packaged rooftop unit. The DSI control board serves as the central intelligence of the heating system — it manages and sequences combustion, coordinates the blower and indoor motors, fires the spark igniter, opens the gas valve, and continuously monitors flame sensing and safety lockout timers. When this board fails, the unit may attempt ignition and lock out, fail to produce heat entirely, or exhibit erratic cycling behavior that no other single component can explain.

• OEM Part Number: LH33WP003 (also supersedes LH33WP003A) | Factory-direct Carrier replacement | Microprocessor-based DSI logic for precise ignition timing and lockout sequencing
• Key Functions: Controls combustion sequence, blower motor, indoor motor, spark ignitor firing, and gas valve operation | Monitors trial-for-ignition timing, flame sensing signal, and hard lockout conditions
• OEM vs Generic: OEM boards use factory-programmed microprocessors with exact timing parameters for the PY3PPA036090AB. Aftermarket boards may use generic timing curves that cause nuisance lockouts, void equipment warranties, or fail to meet original safety specifications.
• Install Difficulty: 3/5 — Disconnect power and verify zero voltage before handling. Tools needed: ¼" nut driver, flathead screwdriver, needle-nose pliers, multimeter. Photograph all wiring harness connections before removal. Observe proper ESD precautions when handling the board.
• Warranty: 1-year OEM manufacturer warranty. Ships same business day from our warehouse.

Compatibility: Direct OEM replacement for Carrier model PY3PPA036090AB packaged rooftop units. Verify your existing board's part number label before ordering. Compatible with LH33WP003 and LH33WP003A suffix variants. Questions about fitment? Our HVAC parts specialists verify compatibility before you order — ships same day.