OEM Carrier Direct Spark Ignition (DSI) Control Board LH33WP003 for Model PY3PNA024040NB

This is the genuine OEM Carrier Direct Spark Ignition (DSI) control board, part number LH33WP003, factory-specified for the Carrier PY3PNA024040NB packaged rooftop unit. The DSI control board is the brain of your heating system — it orchestrates the entire ignition sequence from inducer pre-purge through spark ignition, flame sensing, gas valve activation, and blower motor staging. When this board fails, you'll typically experience a complete no-heat condition, repeated ignition lockouts, or a unit that attempts ignition and then faults out after one to three trials. Intermittent heating, failure to prove flame, or a board with no LED activity are all telltale signs this component needs replacement.

• Part Function: Microprocessor-based DSI control — manages spark igniter, gas valve, inducer motor, blower fan motor, and all limit/safety switch monitoring in sequence
• OEM vs Generic: This is the genuine Carrier factory board, engineered to exact specifications for the PY3PNA024040NB. Aftermarket substitutes may approximate function but often lack precise timing tolerances and full safety interlock compatibility, which can affect reliability and longevity.
• Install Difficulty: 4/5 — Requires disconnecting 24V control wiring harnesses, high-voltage blower leads, and flame-sense connections. Photograph all wiring before removal. Tools needed: #2 Phillips screwdriver, 1/4" nut driver, multimeter, insulated gloves. Always shut off gas supply and disconnect power at the disconnect box before beginning.
• Warranty: 1-year OEM factory warranty. In stock and ships same business day from our warehouse.

Compatibility: Designed for the Carrier PY3PNA024040NB packaged rooftop unit. Verify your OEM part number on the existing board or the unit data plate before ordering. Compatible board dimensions are 5 × 7 × 1.875 inches. Not sure it fits? Our HVAC parts specialists verify fitment before you buy — contact us today. Orders placed before 3 PM ship the same business day.