OEM Carrier Direct Spark Ignition (DSI) Control Board LH33WP003 for Model PY1PNB024040AAAA

This is the genuine OEM Carrier Direct Spark Ignition (DSI) control board, part number LH33WP003, factory-specified for the Carrier PY1PNB024040AAAA packaged rooftop unit. As the brain of the heating system, this microprocessor-based board manages the entire ignition sequence — controlling the spark igniter and gas valve, orchestrating inducer and blower fan motor operation, monitoring flame sensing, and enforcing safety lockout protocols. When this board fails, typical symptoms include a complete no-heat condition, repeated ignition lockout faults, erratic blower behavior, or the unit failing to advance past the pre-purge stage.

• Specs: Direct Spark Ignition (DSI) microprocessor control | Manages combustion, blower, and indoor fan motors | Monitors limit switches, pressure switches, and flame rod | Built-in LED fault code diagnostics | Pre-purge and post-purge sequencing | Manual-reset lockout on ignition failure
• OEM vs Generic: This is a genuine Carrier factory part — not a third-party substitute. OEM boards are programmed to exact timing sequences (trial for ignition, retry intervals, lockout thresholds) specific to Carrier rooftop equipment. Generic boards may introduce timing mismatches that trigger nuisance lockouts or void equipment warranties.
• Install difficulty: 3/5 — Disconnect power at the disconnect and verify zero voltage before handling the board. Tools needed: flat-head and Phillips screwdrivers, needle-nose pliers, smartphone (photograph all wiring harness connections before removal). Transfer connectors one at a time to avoid miswiring. Recommended for qualified HVAC technicians.
• Warranty: 1-year OEM factory warranty against defects in materials and workmanship. Ships same business day from our warehouse.

Compatibility: Designed as the direct factory replacement for Carrier model PY1PNB024040AAAA packaged rooftop units. Also replaces superseded suffix variant LH33WP003A. Verify your existing board's part number on the label before ordering. Need fitment confirmation? Our HVAC parts specialists verify compatibility before you buy — contact us today and get this part shipped out the same day.