OEM Carrier Direct Spark Ignition (DSI) Control Board LH33WP003 for Model PY1RJA048074AAWA

This is the factory OEM Direct Spark Ignition (DSI) control board for the Carrier PY1RJA048074AAWA packaged rooftop unit. As the microprocessor brain of the heating system, this board orchestrates combustion sequencing, spark ignition, gas valve activation, flame sensing, blower motor control, and safety lockout logic. When it fails, symptoms typically include hard lockout after ignition attempts, no-heat calls going unanswered, erratic cycling, or the system shutting down immediately after startup — often accompanied by a fault code flashed at the board's diagnostic LED.

• OEM Part Number: LH33WP003 | Direct Spark Ignition (DSI) type | Microprocessor-based combustion sequencing | Factory-matched timing for trial-for-ignition and flame sensing
• OEM vs Generic: This is a genuine Carrier OEM board — not an aftermarket substitute. OEM boards retain exact factory timing parameters, lockout logic, and connector pinouts, eliminating the calibration drift and wiring adapter issues common with third-party replacements.
• Install Difficulty: 3/5 — Requires safe lockout/tagout of high-voltage supply before servicing. Tools needed: 1/4" nut driver, Phillips screwdriver, needle-nose pliers, and a multimeter for pre- and post-install voltage verification. Photograph all wiring harness connections before disconnecting. Recommend licensed HVAC technician for rooftop unit service.
• Warranty: 1-year OEM manufacturer warranty. In-stock and ships same business day from our warehouse.

Compatibility: Engineered as the factory-specified replacement for Carrier model PY1RJA048074AAWA packaged rooftop units equipped with Direct Spark Ignition heating. Always cross-reference the part number on your existing board before ordering. Have a fitment question? Our HVAC parts specialists verify compatibility before you buy — no guesswork required.