OEM Lennox Furnace Pressure Switch — 34M76
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The genuine OEM Lennox 34M76 pressure switch safeguards your furnace by verifying that the inducer draft and combustion airflow are correct before ignition is allowed. It senses the pressure differential generated by the draft inducer and only permits the sequence to continue when venting is confirmed safe, preventing dangerous flue gas conditions inside your home.
Common failure symptoms: When the 34M76 fails, the furnace typically won't light, locks out on a pressure error, short-cycles, or repeatedly attempts ignition before shutting down. A diaphragm that sticks open, a switch that fails to close, or debris in the pressure tubing are frequent culprits.
Why OEM matters: Each Lennox pressure switch is factory-calibrated to a precise trip point matched to your furnace's inducer and vent design. A substitute switch with an incorrect set point can create nuisance faults or bypass an essential safety check. The 34M76 is the exact OEM component your Lennox system was engineered to use, delivering dependable operation and rated safety.
Shipping Information
- Orders placed before 3PM CST ship same business day
- Standard delivery: 2-5 business days
- Express shipping available at checkout
- Free shipping on orders over $75
- Tracking number emailed upon shipment
Return Policy
- 30-day returns on unused parts in original packaging
- Electrical parts (capacitors, contactors, control boards) are final sale once installed
- Email info@nationalhvacparts.com to initiate a return
- Refunds processed within 5-7 business days