01
Find the Nameplate
Every HVAC unit has a metal data plate — on the side of outdoor units, inside the cabinet door of furnaces and air handlers. It has the model and serial number you need.
02
Read the Model Number
The model number encodes equipment type, tonnage/BTU, SEER rating, and vintage. Use our decoder guides below or enter it directly in the Part Finder.
03
Match the Part Specs
For most parts, physical specs (voltage, uF, HP, frame size) must match exactly. OEM part numbers ensure perfect fit. Aftermarket parts list cross-references.
04
Verify Before Installing
Compare old and new parts before installation. Check terminals, wiring positions, mounting holes, and rotation direction on motors.
DECODING MODEL NUMBERS
The model number is the single most important piece of information for finding the right part. Here's how to read the most common brands.
Carrier / Bryant / Payne
Example: 24ACC636A003 — 24A = product family, CC = scroll compressor, 6 = R-410A, 36 = 3 tons, A = revision. The 3-ton designation (36) means 36,000 BTU/hr.
FORMAT: 24[FAMILY][VOLTAGE][TONS][REVISION][CONFIG]
Goodman / Amana
Example: GSX160481 — G = Goodman, S = split system, X = standard efficiency, 16 = 16 SEER, 048 = 4 tons (48,000 BTU), 1 = single phase.
FORMAT: [BRAND][TYPE][EFFICIENCY][BTU][PHASE]
Trane / American Standard
Example: 4TTR3036L1000A — 4T = Trane residential, T = air conditioner, R3 = R-410A efficiency tier, 036 = 3 tons, L = multi-speed, 1 = single phase.
FORMAT: 4T[PRODUCT][REFRIGERANT][TONS][CONFIG]
Lennox
Example: XC21-036-230 — XC21 = product line and SEER tier, 036 = 3 tons, 230 = 230V single phase.
FORMAT: [LINE]-[TONS]-[VOLTAGE]
PART-SPECIFIC MATCHING GUIDES
Capacitors — Run & Start
Match capacitance (MFD/uF) within ±6% of original. Match or exceed voltage rating. Physical size affects bracket fit. Dual run caps: HERM terminal = compressor uF, FAN terminal = condenser fan motor uF.
Condenser Fan Motors
Must match: HP, voltage, RPM, rotation direction (usually CCW viewed from blade side), frame diameter, shaft length and diameter. Always test or replace the run capacitor first — most "bad motor" calls are a failed cap.
Contactors
Match coil voltage (almost always 24V AC residential), number of poles (2-pole for standard residential), and contact amperage rating (30A, 40A, or 60A). Replace if contacts are pitted, burned, or contacts weld closed.
Ignitors
Match voltage (120V most common), wattage, mounting hole pattern, and tip configuration. Silicon carbide vs silicon nitride — most modern furnaces use silicon nitride (more durable). OEM part number ensures exact fit.
Control Boards
Boards are model-specific. Use the exact OEM part number from the board sticker or furnace data plate. Universal boards require extensive wiring work. Use OEM whenever possible.