Lennox 71M28 Control Board R-410A Even a small amount of

Even a small amount of condensate can prevent the diaphragm from sensing the correct differential pressure

a critical tool for commissioning and troubleshooting leaky systems

If your furnace or air handler codes for "Pressure Switch Open

When troubleshooting Rheem furnace wiring or heat pump control circuits

Lennox 71M28 Control Board R-410A Even a small amount ofThe Lennox 71M28 Control Board is a genuine OEM replacement kit (MCC1 1) designed for critical system management in Lennox, Armstrong, and AirEase packaged units. Also identified by part number 71M2801 and older designations like LB 106199A or 56M99, this integrated furnace control directs essential operations including ignition sequence, blower motor timing, and continuous safety circuit monitoring. Engineered for 120V AC applications, it is a direct