OEM Carrier Direct Spark Ignition (DSI) Control Board LH33WP003 for Model PY1PPA036100ADBA

This is the factory OEM Direct Spark Ignition (DSI) control board for the Carrier PY1PPA036100ADBA packaged rooftop unit. As the brain of the heating system, this board manages every critical ignition sequence function — from spark generation and gas valve activation to blower motor staging, flame sensing, and safety lockout. When this board fails, you may experience a complete no-heat condition, repeated ignition lockouts, incorrect blower timing, or persistent fault codes on the unit's LED diagnostic display.

• Part Number: LH33WP003 | Direct Spark Ignition (DSI) Integrated Circuit Board | Factory OEM — engineered to Carrier's original design specifications for the PY1PPA036100ADBA
• Key Functions: Controls spark ignition, gas valve activation, combustion blower and indoor fan motors, flame sensing, trial-for-ignition timing, and safety lockout sequences — with microprocessor-based LED fault code diagnostics for faster troubleshooting
• OEM vs Generic: The OEM LH33WP003 is built to exact factory tolerances, ensuring proper timing sequences, flame-sensing sensitivity, and motor staging. Generic aftermarket boards may have mismatched timing parameters that cause nuisance lockouts or accelerated secondary component wear.
• Install Difficulty: 3/5 — Requires disconnecting 120V line power and 24V control wiring harnesses. Tools needed: nut driver set, needle-nose pliers, multimeter, phone/camera to photograph all wiring before removal. Recommend verifying gas valve wiring polarity before powering on. Professional installation strongly advised.
• Warranty: 1-year OEM factory warranty. Ships same business day from our NationalHVACParts.com warehouse.

Compatibility: This OEM control board is the factory-specified replacement for the Carrier PY1PPA036100ADBA packaged rooftop unit. Always verify your existing board's part number (LH33WP003 or LH33WP003A) against your unit's data plate before ordering. Have a question about fitment? Our HVAC parts specialists verify compatibility before you buy — contact us today and get your unit back online fast.