the small 1/32" orifice and normally closed configuration are specifically designed to manage high-pressure differentials across the seat while maintaining a tight shut-off

among others

it ensures consistent belt alignment and optimal power transfer from the drive motor to the fan shaft

While designed for 2-stage heaters

Always verify your specific model number and serial number against the manufacturer’s parts list to confirm exact fitment

Lochinvar & A.O. Smith 100093749 Thermostat 321894-709 the small 1/32" orifice andThe Lochinvar & A. O. Smith 100093749 Thermostat Kit is a critical OEM replacement part for maintaining thermal calibration in residential and commercial water heaters and boilers. Designed as a direct swap for the R110 control, this kit features a 1. 5 inch shank and a 42. 75K LP low pressure sensor, ensuring precise signal feedback to the burner assembly. This thermostat is optimized for natural gas and propane (LP) fire ups where precise