Visual Diagnostics: Built-in status indicator light allows for instant troubleshooting of the 24Vac control circuit

Always verify the appliance nameplate and use a digital manometer for final calibration

Designed for seamless compatibility with Johnson Controls V-3000 series actuators with a 5/16" stroke

Can this wrench be used on suction and liquid line valves

Verify the color coding (Red/Red) and the fixed temperature rating (190°F) against your furnace's service manual

Cleveland Controls DFS-221-156 Switch Visual Diagnostics: Built-in status indicatorThe Cleveland Controls DFS 221 156 is a heavy duty, fixed point air pressure sensing switch engineered for precision airflow verification in HVAC, duct heater, and combustion systems. As a direct FS BO 179 cross reference, this SPDT switch is factory calibrated to actuate on a pressure rise of 0. 05" w. c. (+ 0. 02"), making it a critical safety component for proving draft in boilers and furnaces. Its open mounted design is specifically optimized for