the 70021517 features a 42Y frame and an open air-over (OAO) enclosure

Advanced Programming: Pre-programmed logic ensures correct ramp speeds and torque profiles for furnace and air handler blower wheels

This 2-stage natural gas valve operates on a standard 24V alternating current control circuit and is factory-calibrated for a 3

Precision Thermal Response: Ensures the system shuts down accurately at 150°F to protect the heat exchanger from permanent thermal damage

often necessary for tight clearances or legacy linkage setups

Watts 0121429 Valve 322838-752 the 70021517 features a 42YThe Watts 0121429 (Model LFLL40XL) is a heavy duty, 3 4 inch temperature and pressure relief valve designed specifically for commercial hot water heaters and supply tanks. Engineered with an extended shank, this valve is the industry standard for installations involving high density insulation, eliminating the need for additional extension nipples. The lead free cast copper silicon alloy construction ensures compliance with rigorous NSF ANSI 61