LG

Inverter-driven outdoor unit feeding one or more wall, ceiling or compact-ducted heads over a communicating line. The fastest-growing machine in both segments.

Inverter boards, communicating controls and electronic expansion valves — not the contactor-and-run-cap machine the board models, and dedicated mini-split tickets are on the roadmap. From the A2L start-up guide, the refrigerant handling, nitrogen and deep-vacuum discipline transfer; its charge-to-subcooling step does not — these machines charge by weight to the manufacturer’s line-length math, behind flares torqued to spec. On the call itself, flash codes and the manufacturer’s service data lead.

Open in the Copilot (reference) →

One refrigerant system serving many zones through branch boxes — increasingly the backbone of new multi-family and light-commercial buildings.

Manufacturer-certified territory: controls, addressing, commissioning and refrigerant piping are proprietary per maker — the ducted-split start-up guide does not commission these systems. Fundamentals, A2L handling and electrical safety transfer; the specific diagnostics do not. Get the factory training for the system you service.

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The under-window wall-sleeve unit in hotels, apartments and senior living — cooling with electric heat (PTAC) or a heat pump (PTHP), each serving one room.

Run capacitors, fan motors, plugged drains and matted coils — the RUNS-BUT-WON’T-COOL and GAUGES wings teach the same failures; dedicated PTAC tickets are on the roadmap. Respect the supply: many commercial buildings feed PTACs 265V, which is not the 115V habit you brought from residential.

Open in the Copilot (reference) →Practice: runs but won’t cool →Practice: gauges on →