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