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Armstrong Air

Lennox International · Single-family homes · Apartments & multi-family

Allied Air’s (Lennox International) flagship through independent distribution: conventional splits and furnaces with standard controls — service-friendly by design.

The family: Lennox, the Allied Air set (Armstrong Air, AirEase, Ducane, Concord), ADP coils and air handlers, and Magic-Pak wall units.

Same family: Lennox, AirEase, Ducane, Concord, ADP (Advanced Distributor Products), Magic-Pak

What they make

Split system A/C (straight cool)

Covered in the simulator

Outdoor condenser plus an indoor furnace-and-coil or air handler — the most common machine in single-family homes and garden-style multi-family.

The whole sim is built on this machine: every wing of the board and the guided no-cool flow apply directly.

Heat pump (split)

Lessons carry over

A split system that also heats: one reversing valve decides which coil condenses. Everything a straight-cool split has, plus the O (or, on some brands, B) circuit and defrost.

The HEAT PUMP wing of the board works the reversing valve; the guided flow routes heat pumps to escalation until its playbook ships. The electrical side transfers one-for-one.

Gas furnace

Covered in the simulator

The indoor half of most split systems outside the Sun Belt: burners and heat exchanger below, the A-coil above, the 24V control system inside.

The control side — door switch, transformer, board, blower, low-voltage fuse — is fully modeled as the sim’s indoor cabinet, and the guided flow applies on cooling complaints. Combustion-side diagnostics are on the roadmap.

Air handler / fan coil

Covered in the simulator

The all-electric indoor cabinet: blower, coil, and controls. In multi-family it hides in closets and mechanical rooms; hydronic fan-coil versions swap the coil’s refrigerant for water.

Modeled as the sim’s indoor unit: control power, blower circuits, condensate float, coil airflow. Hydronic (water-coil) versions add loop diagnosis the sim doesn’t model yet.

Evaporator coil

Covered in the simulator

The indoor coil itself — cased or uncased, A, N or slab — often replaced separately from everything else, which is where mismatches are born.

Freeze-ups, restrictions, airflow starvation and mismatched-coil audits are all on the board, and the guided flow’s superheat/subcooling paths read straight through it. Match by capacity and metering device, never by badge.

Package unit

Lessons carry over

The whole system in one outdoor cabinet — on a pad beside the house or on the roof. Gas/electric, straight cool, or heat pump.

Same parts, one cabinet: contactors, dual-run caps, PSC/ECM motors and the refrigerant circuit fail exactly like the board’s scenarios. The guided flow’s split-system routing doesn’t fit a single cabinet, so it escalates package units by design.

Tech support

Tech support here is the guided Copilot with your Armstrong Air info already loaded — one question at a time, evidence before parts, and everything you enter rides into the service report.

Start tech support — Armstrong Air loaded

Opens the guided Copilot with Armstrong Air already on the equipment card.

Reading Armstrong Air model numbers

Lennox writes series-dash-size: 14ACX-036 reads 14 SEER / ACX line / 036 = 3 tons; XC16-048 is the Elite 4-ton. Allied Air brands (Armstrong, AirEase, Ducane, Concord) use 4SCU/4SHP-style prefixes with the same trailing size. Furnaces (ML195, EL296V, SLP98V) put AFUE in the name and heating input elsewhere — don’t read furnace digits as tonnage. Magic-Pak all-in-ones put cooling capacity in the TRAILING block (…-241/-301/-361 = 2 / 2.5 / 3 tons); the digit right after MHP/MGE is the series generation and the middle token is the efficiency class — neither is a size.

  • 14ACX-036-230Lennox Merit split A/C, 14 SEER, 3 tons (036).
  • 4SCU16LS148PAllied Air split A/C, 16 SEER, 4 tons (48).

Thirty years of these units

1990s–2000s: 10ACB/12HPB R-22 era. 2010s: 13ACX/14ACX/XC lines on R-410A. 2020s: EL/SL variable-capacity and A2L transitions.

Lennox residential packages (LRP14/LRP16) put tonnage right in the model: LRP14AC36 = 3 tons.

Dating a unit from the serial

Lennox serials lead with plant digits then two year digits (e.g., 5807C… → 2007). Allied brands differ — check the family table. Serial 5807C12345 → 2007 build.

Common rule — spot-check against the manufacturer’s table

Need the wiring? The practice board’s ladder diagram is live and interactive — the same circuit these units share, with a meter on it. Open the board →

All manufacturer and brand names are trademarks of their respective owners, used here only to identify equipment technicians encounter in the field. HVACSim is independent: not affiliated with, endorsed by, or sponsored by any equipment manufacturer. Simulated behavior is generic — on real equipment the manufacturer’s service literature, nameplate and installation instructions always govern. Corporate ownership, product lines and brand relationships change; catalog information last verified August 2026.

HVACSim equipment guide — training reference, not manufacturer documentation.