When you are troubleshooting a furnace not heating

for low-temp applications

Is the output polarity sensitive

and terminals

The 5502-136M features a standard 2-1/8 inch "D" stem

Honeywell MS7520A2007 Actuator Refrigerant When you are troubleshooting aThe Honeywell MS7520A2007 is a heavy duty S20 Series Spring Return Direct Coupled Actuator designed for precise control of dampers and valves in commercial HVAC systems. This 24V damper actuator delivers 175 lb in (20 Nm) of torque, making it a reliable solution for air handling units, economizers, and vent structures requiring fail safe performance. It supports modulating (0 2 10 Vdc), 4 20 mA (with included 500 Ohm resistor), and floating control