OEM Carrier Pressure Switch w/ Bracket -1.81" WC for Model PG9MAB048100AASA

This OEM pressure switch (part number HK06NB124) is the factory-specified replacement for the Carrier PG9MAB048100AASA furnace. The pressure switch monitors negative pressure created by the inducer motor to verify proper venting before allowing the ignition sequence to proceed. When the switch fails or its diaphragm weakens, the furnace will lock out before ignition — commonly triggering an error code 31 (pressure switch stuck open) — leaving you with no heat. This part ships with the factory mounting bracket included, matching the original installation footprint exactly.

• Specs: -1.81" W.C. (water column) set point | SPST (Single-Pole, Single-Throw) | Normally Open | Factory-matched Honeywell diaphragm assembly | Includes OEM mounting bracket
• OEM vs Generic: This is a genuine OEM Carrier part built to exact factory pressure tolerances. Off-brand switches frequently drift from their rated W.C. set point, causing nuisance lockouts or — worse — failing to detect a true venting fault, which is a safety hazard.
• Install difficulty: 2/5 — Disconnect power and gas before beginning. Tools needed: 1/4" and 5/16" nut drivers, needle-nose pliers, phone camera for reference photos. Note hose port orientation carefully — ports are labeled (+) and (–), and one port contains a flow restrictor that must be matched to the original. Spade terminals are different sizes and are keyed to prevent mis-wiring.
• Warranty: 1-year OEM manufacturer warranty against defects. In stock and ships same business day from our warehouse.

Compatibility & Supersession: Fits Carrier model PG9MAB048100AASA and over 200 additional Carrier and Bryant residential furnace models. This part supersedes and directly replaces obsolete part numbers HK06NB119, HK06NB120, HK06NB122, and HK06ZB104. Always verify the W.C. rating on your existing switch's data label before ordering. Not sure it fits? Our HVAC parts team verifies fitment before you order — just ask.