Universal Replacement: Direct 1:1 replacement for the Honeywell ST9103A1028 electronic fan timer

commercial building HVAC systems

This switching relay features a 30A resistive load rating at 60Hz

Precision Calibration: Factory calibrated at 20 PSIG to provide a reliable 8 PSIG output signal when the room temperature matches the dial setting

High-Durability Construction: Cast bronze body with brass trim and EPDM packing rated for fluid temperatures up to 284°F

Lochinvar & A.O. Smith 100109721 Upper Probe 320735-701 Universal Replacement: Direct 1:1 replacementThe Lochinvar & A. O. Smith 100109721 Upper Probe is a critical OEM replacement part engineered for the inner control assembly of high efficiency commercial water heaters. As a high performance hot surface igniter, this 100109721 probe is essential for ensuring reliable ignition cycles and precise flame sensing in BTH Series units. Designed to meet exact factory specifications, it eliminates the common failure points associated with generic