OEM Carrier Direct Spark Ignition (DSI) Control Board LH33WP003 for Model PY1PJB048130NBAA

This is the genuine OEM Direct Spark Ignition (DSI) Control Board for the Carrier PY1PJB048130NBAA packaged rooftop unit. As the brain of the heating sequence, this microprocessor-based board orchestrates the entire combustion cycle — energizing the spark igniter and gas valve, controlling the blower and indoor motors, monitoring trial-for-ignition timing, validating flame sensing, and executing safety lockout if an unsafe condition is detected. When this board fails, symptoms typically include: no heating response, repeated ignition lockout faults, erratic blower behavior, or the unit shutting down immediately after a heat call.

• OEM Part Number: LH33WP003 (also supersedes LH33WP003A) | Factory-specified replacement for Carrier PY1PJB048130NBAA rooftop packaged units
• Function: Microprocessor-based DSI board — controls spark ignition, gas valve sequencing, combustion blower, indoor fan motor, flame sensing, and safety lockout logic
• OEM vs Generic: This OEM board is programmed to exact factory timing and lockout parameters for your unit. Aftermarket boards (e.g., ICM291) may require jumper configuration and can introduce timing variances — OEM is always the zero-risk fitment choice for commercial rooftop applications.
• Install Difficulty: 3/5 — Disconnect power at the disconnect box before beginning. Tools needed: 1/4" and 5/16" nut drivers, needle-nose pliers, phone camera (photograph all wiring harness connections before removal). Transfer connectors one at a time to avoid mis-wiring. Verify 24V control power at transformer before condemning the board.
• Warranty: 1-year OEM manufacturer warranty. Ships same business day from our warehouse.

Compatibility: Designed for the Carrier PY1PJB048130NBAA packaged rooftop unit. This board is also referenced across compatible Carrier, Bryant, and Day & Night rooftop platforms using the LH33WP003/LH33WP003A ignition control. Always verify your existing board's part number against LH33WP003 before ordering. Have a question about fitment? Our HVAC parts specialists verify compatibility before you buy — contact us today. In stock and ships today.