OEM Lennox Control Transformer — 38631
OEM Guaranteed
Same-Day Ship
30-Day Returns
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The genuine OEM Lennox 38631 transformer steps down line voltage to the low-voltage control power your Lennox system's thermostat, relays, contactor coil, and control board depend on. Without steady 24V control power, none of the system's switching components can energize, so this transformer is central to reliable heating and cooling operation.
Common failure symptoms: A failed transformer leaves the system completely dead on the low-voltage side — a blank thermostat, no response to calls for heat or cool, and no clicking from the contactor. Transformers often burn out from a shorted control wire, a stuck contactor coil, or an overloaded secondary, sometimes with a visible scorch or burnt smell.
Why OEM matters: The Lennox 38631 is matched to your equipment's primary voltage and secondary VA load, so it supplies clean, correctly rated control power without overheating. An undersized or wrong-voltage substitute can nuisance-trip, fail early, or under-power the contactor and board. The OEM part ensures proper fit and warranty compliance. In stock and ships same day when ordered before 3PM CST.
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