Goodman
Daikin’s volume brand — everywhere in replacement and new construction. Simple, serviceable, aggressively priced; newer models move onto Daikin inverter platforms and R-32.
The family: Daikin — the world’s largest HVAC manufacturer — plus Goodman and Amana (including the Amana PTAC line) in North America.
Same family: Daikin, Amana (HVAC & PTAC)
What they make
Split system A/C (straight cool)
Covered in the simulatorOutdoor 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.
Start a guided call →Practice: whole system dead →Practice: outdoor unit dead →Practice: runs but won’t cool →Practice: no air inside →Practice: acting possessed →Practice: blows fuses →Practice: gauges on →Practice: wrong part, wrong size →A2L start-up guide →
Heat pump (split)
Lessons carry overA 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.
Open in the Copilot (reference) →Practice: heat pump →Practice: whole system dead →Practice: outdoor unit dead →Practice: runs but won’t cool →Practice: no air inside →Practice: acting possessed →Practice: blows fuses →Practice: gauges on →Practice: wrong part, wrong size →A2L start-up guide →
Gas furnace
Covered in the simulatorThe 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.
Start a guided call →Practice: whole system dead →Practice: no air inside →Practice: acting possessed →Practice: blows fuses →
Air handler / fan coil
Covered in the simulatorThe 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.
Start a guided call →Practice: whole system dead →Practice: no air inside →Practice: runs but won’t cool →Practice: acting possessed →Practice: blows fuses →Practice: gauges on →A2L start-up guide →
Evaporator coil
Covered in the simulatorThe 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.
Start a guided call →Practice: gauges on →Practice: runs but won’t cool →Practice: wrong part, wrong size →A2L start-up guide →
Package unit
Lessons carry overThe 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.
Open in the Copilot (reference) →Practice: runs but won’t cool →Practice: blows fuses →Practice: gauges on →
Tech support
The Copilot loads your Goodman equipment details. Guided diagnostic coverage depends on the equipment type; ductless and monoblock systems currently use the reference library.
Opens the guided Copilot with Goodman already on the equipment card.
Reading Goodman model numbers
Letters lead, size follows. Condensers: GSX (Goodman split cooling), GSZ (heat pump), ASX/ASZ (Amana), DX (Daikin badge) — then efficiency, then the size code: GSX140361 reads GSX / 14 SEER / 036 = 3 tons. Air handlers ARUF, ASPT, AMST and coils CAPF/CHPF carry matching size codes. Gas furnaces (GMES, GMVC, AMVC) code HEATING INPUT instead: GMVC960803 is 80,000 BTU input — not a cooling size.
GSX160361— Goodman split A/C, 16 SEER, 3 tons (036), single-stage.ASZ160481— Amana heat pump, 16 SEER, 4 tons (048).ARUF37C14— Air handler, multi-position, 3-ton class coil (37).
Thirty years of these units
Mid-1990s–2000s: R-22 era (GSC/CK/CLJ series). ~2007–2024: R-410A GSX/ASX generations. 2024–25: R-32 arrives with the GLXS/DX era. The size grammar stayed steady the whole way — the refrigerant on the data plate is your era tell.
Package units: GPC (A/C), GPH (heat pump), GPG (gas/electric) with the same size codes — GPC1436H41 is a 3-ton package A/C.
Dating a unit from the serial
First four digits are year + month of manufacture (YYMM). Serial 0607123456 → July 2006.
Reliable rule for this family
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 →