OEM Carrier Direct Spark Ignition (DSI) Control Board LH33WP003 for Model PY1RJA048115AAWA

This is the factory OEM Direct Spark Ignition (DSI) control board for the Carrier PY1RJA048115AAWA packaged rooftop unit. The DSI control board is the brain of the heating system — it orchestrates the entire ignition sequence, including managing the spark igniter and gas valve, monitoring flame sensing, enforcing trial-for-ignition timing, and triggering safety lockout if an unsafe condition is detected. When this board fails, common symptoms include the unit entering hard lockout with no heat, intermittent ignition failures, short cycling on the heating call, or erratic blower and gas valve behavior that cannot be traced to the igniter or flame sensor alone.

• OEM Part Number: LH33WP003 (also supersedes LH33WP003A) | Microprocessor-based DSI control | Direct drop-in replacement — no modifications required
• Board Functions: Controls combustion sequence, spark igniter firing, gas valve operation, blower motor timing, flame sensing signal, trial-for-ignition countdown, and automatic safety lockout
• OEM vs Generic: This is the genuine Carrier OEM board, factory-programmed to exact timing and lockout specifications for the PY1RJA048115AAWA. Aftermarket boards may use approximate timing values, increasing risk of nuisance lockouts or premature gas valve wear.
• Install Difficulty: 3/5 — Disconnect power and gas before servicing. Document all wire harness connections with photos before removal. Tools needed: 1/4" and 5/16" nut drivers, needle-nose pliers, phone camera for wiring reference. Recommend professional installation for rooftop units.
• Warranty: 1-year OEM manufacturer warranty. Ships same business day from our climate-controlled warehouse.

Compatibility: Direct factory replacement for Carrier model PY1RJA048115AAWA packaged rooftop unit. Verify your existing board's part number (LH33WP003 or LH33WP003A) against your unit's data plate before ordering. Our parts specialists are available to confirm fitment — reach out before you order if you have any questions. In stock and ships today.