OEM Lennox Adjustable Fan/Limit Thermostat 175-215°F — 27P99
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The Lennox 27P99 is a genuine OEM adjustable fan and limit thermostat with a 175–215°F temperature range and a 40°F differential. It performs two jobs in your furnace: it energizes the blower once the heat exchanger warms up, and it acts as a high-limit safety switch that shuts the burners down if the plenum overheats. This dual function keeps your Lennox furnace running efficiently while protecting the heat exchanger from thermal damage.
Common failure symptoms: When the 27P99 fails or drifts out of calibration, you may notice the blower short-cycling, the fan running constantly, no warm air delivery, or the furnace tripping on the limit and locking out. A worn or corroded bimetal element frequently causes these issues.
Why OEM matters: Lennox furnaces are engineered around precise fan-on/fan-off and limit setpoints. Using the factory-spec 27P99 guarantees the correct temperature calibration, terminal layout, and probe length for a safe, direct fit — no field modification or guesswork. Generic substitutes can trip early, delay blower engagement, or fail to protect the heat exchanger. Insist on genuine OEM to preserve your equipment's safety rating and warranty.
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