OEM Carrier Direct Spark Ignition (DSI) Control Board LH33WP003 for Model PY3GNA048115AB

This is the genuine OEM Direct Spark Ignition (DSI) control board for the Carrier PY3GNA048115AB packaged gas/electric unit. As the brain of the heating system, the LH33WP003 control board manages and sequences every critical heating function — it fires the spark igniter, opens the gas valve, monitors the flame sensor, and controls both the blower and inducer motors. When this board fails, common symptoms include hard lockout after an ignition attempt, a furnace that starts briefly then shuts down, a blower that runs continuously or not at all, or a completely unresponsive unit with no call-for-heat response.

• Part Number & Type: OEM Carrier LH33WP003 | Direct Spark Ignition (DSI) Microprocessor-Based Control Board | Also supersedes LH33WP003A
• OEM vs Generic: The genuine Carrier LH33WP003 uses factory-calibrated timing sequences for trial-for-ignition and lockout — critical tolerances that aftermarket boards may not replicate exactly, risking nuisance lockouts or unsafe gas valve timing.
• Install Difficulty: 3/5 — Shut off gas supply and 120V power before beginning. Photograph all wiring harness connections before removal. Tools needed: 1/4" nut driver, Phillips screwdriver, needle-nose pliers. Note all DIP switch or jumper settings on the old board before swapping. Verify operation through a full heat cycle after installation.
• Warranty & Shipping: 1-year OEM factory warranty. In stock — ships same business day from our warehouse.

Compatibility: Designed for the Carrier PY3GNA048115AB packaged unit. This board is a common rooftop and packaged-unit DSI ignition control also found across Carrier, Bryant, and Payne platforms sharing the same ignition architecture. Always verify your existing part number on the board label before ordering. Have questions about fitment? Our HVAC parts specialists confirm compatibility before you buy — contact us today.