OEM Lennox Defrost Control Board Kit — 15D57
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The genuine OEM Lennox 15D57 defrost control board kit manages the defrost cycle on your Lennox heat pump, monitoring outdoor coil temperature and timing to clear frost buildup during cold-weather operation. It coordinates the reversing valve, outdoor fan, and auxiliary heat so your system sheds ice efficiently and returns to normal heating without wasting energy.
Common failure symptoms: The 15D57 often fails when you notice the outdoor unit icing over and never clearing, a heat pump that runs continuously in defrost, cold air blowing indoors, tripped breakers, or the outdoor fan behaving erratically. Cracked solder joints, corroded terminals, and heat-stressed relays are typical causes of board failure.
Why OEM matters: Lennox control boards are engineered to exact voltage, timing, and relay specifications for their heat pump platforms. Installing the factory 15D57 ensures correct defrost logic, proper sensor compatibility, and reliable communication with the rest of your system — protecting the compressor and preserving rated efficiency. Aftermarket substitutes can mistime cycles and shorten component life. Always confirm the part number matches your unit's rating plate before installing.
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