Smith 100109972 Control Box is a critical replacement component designed for precise sequence control and safety monitoring in high-efficiency commercial boilers and water heaters

ensuring long-term structural integrity and consistent thermal output

Common Questions: Can this kit be used to convert a valve to Propane (LP)

Once the system cools to 135°F

and CTR-921

Carrier EF33CZ256 Gas Valve 320074-702 Smith 100109972 Control Box isThe Carrier EF33CZ256 Gas Valve is a reliable 2 stage gas control designed specifically for liquid propane (LP) applications in high efficiency heating systems. Operating on a standard 24V furnace control circuit, this valve features a low fire setting of 4. 8" WC and a high fire manifold pressure of 10. 5" WC, ensuring precise fuel to air ratios for optimal combustion. As a direct replacement for the EF33CZ256A, this OEM component is commonly found