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This OEM high pressure switch (part number HK02ZA442) is the factory-specified replacement for the Carrier FIOP300501GA unit. The pressure switch is a critical safety component in the combustion air proving circuit — it monitors the negative pressure (draft) created by the inducer motor to verify safe venting conditions before allowing the control board to initiate ignition. When this switch fails or sticks open, the furnace will typically lock out before reaching the ignition stage, leaving you with a no-heat condition and often a diagnostic fault code related to pressure switch failure.
Compatibility: Designed for the Carrier FIOP300501GA. Confirm the W.C. rating stamped on your existing pressure switch matches this replacement prior to installation. If you are unsure of your unit's exact pressure switch specification, our HVAC parts team can verify fitment using your full model and serial number before you order. In stock and ready to ship today — get your system back online fast.