Ensure all line voltage is disconnected before verifying secondary resistance with a multimeter to confirm circuit integrity

providing a 30-degree differential essential for maintaining safe operating parameters in gas-fired or electric heating equipment

loss of charge

Fail-Safe Operation: Reliable spring return functionality ensures the valve returns to the normally closed position upon loss of 120V power

Reznor 123976 Fan Control 30067439-890 Ensure all line voltage isThe Reznor 123976 Fan Control is a critical OEM replacement component engineered for precise thermal management in industrial and commercial heating applications. This F135 40F thermostatic switch is designed to regulate blower fan cycling by monitoring heat exchanger temperatures, ensuring the fan only operates within the 135F to 40F range. By maintaining these specific operational thresholds, the Reznor 123976 prevents the delivery of cold air