OEM Carrier Direct Spark Ignition (DSI) Control Board LH33WP003 for Model PY1RPA048074AAWB

This is the OEM-specified Direct Spark Ignition (DSI) Control Board (part number LH33WP003) for the Carrier PY1RPA048074AAWB packaged rooftop unit. As the brain of your furnace's ignition system, this microprocessor-based board orchestrates the entire heating sequence — controlling the inducer fan, spark igniter, gas valve, and blower motor while continuously monitoring limit switches, flame sensing, and safety lockout timing. When this board fails, common symptoms include a complete no-heat condition, repeated ignition lockouts, a furnace that starts briefly then shuts down, or an unresponsive system after a thermostat call for heat. The integrated status LED provides fault codes to accelerate diagnosis and reduce troubleshooting time in the field.

• Specs: Direct Spark Ignition (DSI) | Microprocessor-based | Compatible with LP and Natural Gas | Pre-purge: 45 sec | Trial for ignition: 5+2 sec | Retry period: every 20 sec for 15 min | Manual reset lockout | Post-purge: 45 sec | Dimensions approx. 5 × 7 × 1.875 in
• OEM vs Generic: The OEM LH33WP003 board meets exact Carrier factory specifications for timing sequences, flame-sensing sensitivity, and lockout thresholds. Aftermarket boards may have timing tolerances that cause nuisance lockouts or premature component wear — the OEM board eliminates that risk entirely.
• Install Difficulty: 3/5 — Shut off all power and gas before beginning. Tools needed: ¼" nut driver, Phillips screwdriver, needle-nose pliers, phone/camera to photograph wiring harness connections prior to removal. Label all connectors before disconnecting. Verify 24V control power is restored after installation and confirm LED status code is clear before test firing.
• Warranty: 1-year OEM factory warranty against defects. Ships same business day from our warehouse — order by 3 PM local time for guaranteed same-day dispatch.

Compatibility: Designed for Carrier model PY1RPA048074AAWB packaged rooftop gas/electric units. Also cross-references LH33WP003A and LH33WP003/3A variants. Always verify your unit's data plate and existing board part number before ordering to ensure exact fitment. Our parts specialists are available to confirm compatibility before you buy.