Johnson Controls D-3153-7 Damper Actuator Els PW 17895 the SZ charge code is

the SZ charge code is recommended by Emerson for both R404A/R507 and newer R448A/R449A retrofit applications

technicians typically wire the compressor contactor through the NC (normally closed) contacts

Selection should be based on the system's total refrigerant charge

Testing for continuity across these terminals while the 24V coil is de-energized will confirm if the sequencer requires replacement

this OEM replacement addresses common failures like stuck contacts or internal heater coil burnout

Johnson Controls D-3153-7 Damper Actuator Els PW 17895 the SZ charge code isThe Johnson Controls D 3153 7 is a heavy duty pneumatic damper actuator engineered for precise positioning of large dampers in commercial HVAC systems. This piston style actuator features a 15 inch effective diaphragm area and a 3 inch stroke, delivering high torque output for reliable airflow modulation. Built with a rugged die cast aluminum body, it operates on a 0 20 psig control air pressure range and utilizes an 8 13 psi spring range for fail