OEM Lennox Defrost Control Board — 56M37
OEM Guaranteed
Same-Day Ship
30-Day Returns
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The Lennox 56M37 is a genuine OEM defrost control board that manages the defrost cycle on your Lennox heat pump. It monitors coil temperature and elapsed run time, then reverses the system to melt frost and ice from the outdoor coil so your heat pump can operate efficiently in cold weather. This board is manufactured to Lennox specifications for exact fit and dependable defrost timing.
Common failure symptoms include heavy ice buildup on the outdoor unit, a heat pump stuck in defrost mode, no defrost cycle at all, reduced heating output, or the reversing valve and auxiliary heat not sequencing correctly. Erratic operation or a failure to switch between heating and defrost typically points to a faulty control board.
Why OEM matters: Defrost timing and temperature thresholds are calibrated specifically for Lennox heat pumps. A generic board can defrost too often or not enough, wasting energy and stressing the compressor. The genuine 56M37 restores proper defrost logic, protects your compressor, and maintains the efficiency and warranty coverage your Lennox system was designed to deliver.
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