What causes a primary limit switch like the B1370190 to trip

Ensure the flare is clean and free of burrs to maintain an airtight seal with the SAE ends

or 45-second ignition timings

and industrial HVAC equipment

The indicator is accurately calibrated to change at moisture levels generally accepted as the safe operating range for the compressor

Lennox 82W04 40VA Transformer What causes a primary limitThe Lennox 82W04 40VA Transformer is a heavy duty OEM replacement part engineered for constant 120V to 24V step down applications in residential and light commercial HVAC systems. This Class 2 transformer serves as the primary power source for low voltage control circuits, including thermostats, gas valves, ignition modules, and relays. Built to strict Lennox 20298305 specifications, it features a reliable foot mount design for secure installation