OEM Lennox Blower Delay Relay — 45H70
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The genuine OEM Lennox 45H70 blower delay relay controls the timing of your furnace blower, delaying fan startup until the heat exchanger has warmed and keeping the blower running after the burners shut off to purge remaining heat. This timing improves comfort, prevents cold-air blasts, and maximizes the heat extracted from every cycle.
When this relay fails, common symptoms include the blower not starting, the fan running constantly and never shutting off, cold air blowing at the start of a heat cycle, or the blower cycling erratically. A stuck or burned relay can also leave the blower energized indefinitely, wasting energy and wearing out the motor.
Installing the OEM Lennox 45H70 ensures the precise timing intervals and electrical ratings your furnace control sequence depends on. Substitute relays with different delay periods or contact ratings can disrupt the heating cycle and reduce comfort and efficiency. The factory-specified part restores proper blower timing and reliable operation for your Lennox system.
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