If the actuator motor fails

or cracked heat exchangers that cause internal temperatures to exceed the 333-degree rating

For technicians servicing Model M1TW40SF or M1TW50SF units

Using a Lennox 15D57 ensures your system maintains a precise defrost cycle

As an OEM Sterling replacement part

Browning BX44 Belt 322838-754 If the actuator motor failsThe Browning BX44 Belt is a high performance Gripnotch V Belt engineered for demanding HVACR applications where heavy shock loads and small diameter sheaves are common. This BX section cogged belt features a 47 inch nominal outside length and a 45. 8 inch pitch length, providing a 98% energy efficiency rating. Constructed from premium EPDM synthetic rubber, it maintains structural integrity across an expanded temperature range of 60F to +250F, making