HVAC Decoder
Trane Tonnage From Model Number
Where Trane puts the capacity code, what each code means, and the readings that look like capacity but are not. Read out of 6 documents Trane publishes itself, and 3 American Standard publishes, named further down with the date each was fetched.
Starting the decoder. The capacity tables below this box are already loaded, so you can read your code off them now.
Nominal capacity from a model number is a nameplate convention, not a measurement. Actual delivered capacity depends on the matched indoor unit, line set, airflow and conditions. Confirm against the data plate's BTU/h rating and the AHRI certificate for the matched system.
Trane Capacity Codes and Tonnage
R-410A generation
Capacity sits at positions 7-8. Position 6 is the field-connection digit, not part of the capacity, and position 1 is the refrigerant. Example: 4TTR4036N1000.
The tonnage is the one the maker's own document prints for this capacity code; any BTU/h shown beside it is converted from that tonnage.
| Code | Nominal BTU/h | Tons | Code / 12 |
|---|---|---|---|
| 12 | 12,000 | 1 | same answer |
| 18 | 18,000 | 1.5 | same answer |
| 19 | 18,000 | 1.5 | 1.58, so the division is wrong here |
| 24 | 24,000 | 2 | same answer |
| 25 | 24,000 | 2 | 2.08, so the division is wrong here |
| 30 | 30,000 | 2.5 | same answer |
| 31 | 30,000 | 2.5 | 2.58, so the division is wrong here |
| 36 | 36,000 | 3 | same answer |
| 37 | 36,000 | 3 | 3.08, so the division is wrong here |
| 42 | 42,000 | 3.5 | same answer |
| 43 | 42,000 | 3.5 | 3.58, so the division is wrong here |
| 48 | 48,000 | 4 | same answer |
| 49 | 48,000 | 4 | 4.08, so the division is wrong here |
| 60 | 60,000 | 5 | same answer |
| 61 | 60,000 | 5 | 5.08, so the division is wrong here |
Table transcribed from Product and Submittal Data, Outdoor Unit 5HCL9 (DLR-PSD004A-EN, February 2026), published by elibrary.tranetechnologies.com, fetched 2026-07-24.
R-454B Low Profile (ODR-PSD038A-EN)
Capacity sits at positions 7-8 again, but on the Low Profile layout positions 2-3 become a two letter system type (HP heat pump, HC cold climate heat pump) instead of the brand letter and unit type. Example: 5HCL5060B1000A.
The tonnage is the one the maker's own document prints for this capacity code; any BTU/h shown beside it is converted from that tonnage.
| Code | Nominal BTU/h | Tons | Code / 12 |
|---|---|---|---|
| 12 | 12,000 | 1 | same answer |
| 18 | 18,000 | 1.5 | same answer |
| 19 | 18,000 | 1.5 | 1.58, so the division is wrong here |
| 24 | 24,000 | 2 | same answer |
| 25 | 24,000 | 2 | 2.08, so the division is wrong here |
| 30 | 30,000 | 2.5 | same answer |
| 31 | 30,000 | 2.5 | 2.58, so the division is wrong here |
| 36 | 36,000 | 3 | same answer |
| 37 | 36,000 | 3 | 3.08, so the division is wrong here |
| 42 | 42,000 | 3.5 | same answer |
| 43 | 42,000 | 3.5 | 3.58, so the division is wrong here |
| 48 | 48,000 | 4 | same answer |
| 49 | 48,000 | 4 | 4.08, so the division is wrong here |
| 60 | 60,000 | 5 | same answer |
| 61 | 60,000 | 5 | 5.08, so the division is wrong here |
Table transcribed from Inverter Side Discharge Heat Pump 5HCL5 (ODR-PSD038A-EN, December 2025), published by elibrary.tranetechnologies.com, fetched 2026-07-24.
R-454B outdoor units (2026 handbook)
Capacity sits at positions 7-8, with the refrigerant at position 1, the brand at 2, the system type at 3 (C, T, W), the product family at 4, Nominal Rated SEER2 at 5 and the field connection at 6. Example: 5TTR5024A1000AA.
The tonnage is the one the maker's own document prints for this capacity code; any BTU/h shown beside it is converted from that tonnage.
| Code | Nominal BTU/h | Tons | Code / 12 |
|---|---|---|---|
| 12 | 12,000 | 1 | same answer |
| 18 | 18,000 | 1.5 | same answer |
| 19 | 18,000 | 1.5 | 1.58, so the division is wrong here |
| 24 | 24,000 | 2 | same answer |
| 25 | 24,000 | 2 | 2.08, so the division is wrong here |
| 30 | 30,000 | 2.5 | same answer |
| 31 | 30,000 | 2.5 | 2.58, so the division is wrong here |
| 36 | 36,000 | 3 | same answer |
| 37 | 36,000 | 3 | 3.08, so the division is wrong here |
| 42 | 42,000 | 3.5 | same answer |
| 43 | 42,000 | 3.5 | 3.58, so the division is wrong here |
| 48 | 48,000 | 4 | same answer |
| 49 | 48,000 | 4 | 4.08, so the division is wrong here |
| 60 | 60,000 | 5 | same answer |
| 61 | 60,000 | 5 | 5.08, so the division is wrong here |
| 72 | 72,000 | 6 | same answer |
Table transcribed from 2026 Residential and Light Commercial Product Handbook (22-8301-39, Effective 1/1/26), published by elibrary.tranetechnologies.com, fetched 2026-10-01.
The Trane codes that dividing by 12 gets wrong
The usual shortcut is that a capacity code is the nominal BTU/h divided by 1,000, so dividing it by 12 gives the tonnage. Trane prints 7 codes where that arithmetic disagrees with Trane's own table, and the table is what the equipment is sold against:
| Code | Trane prints | Code / 12 gives |
|---|---|---|
| 19 | 1.5 tons | 1.58 |
| 25 | 2 tons | 2.08 |
| 31 | 2.5 tons | 2.58 |
| 37 | 3 tons | 3.08 |
| 43 | 3.5 tons | 3.58 |
| 49 | 4 tons | 4.08 |
| 61 | 5 tons | 5.08 |
These are not derivable, only transcribable, which is why this decoder carries Trane's printed table rather than a formula. If you meet one of these codes in the field, arithmetic will land you between two real sizes, and the printed table is the only thing that resolves it.
Worked example: Trane 4TTR4036N1000
Capacity code 36 at characters 7-8 of 4TTR4036N1000: 36,000 BTU/h, which is 3 tons at 12,000 BTU/h per ton. Positions 7-8 are the nominal capacity code in Trane's own model nomenclature; position 6 is the field-connection digit, not part of it.
- Refrigerant: R-410A. Position 1 digit 4 (2 = R-22, 4 = R-410A, 5 = R-454B).
- Brand letter: Trane. Position 2 letter T, which Trane's legends this reading cites print as TRANE.
- Product type: Split AC condenser. Position 3 character T.
- Efficiency: SEER class 14. Position 5 is the Family SEER digit: Trane's legends 22-1746-04, 22-1725-04, 22-1904-1M-EN each print "4 = 14".
Trane has 3 documented layouts: R-410A generation reads capacity at positions 7-8; R-454B Low Profile (ODR-PSD038A-EN) reads capacity at positions 7-8; R-454B outdoor units (2026 handbook) reads capacity at positions 7-8. They agree on where the capacity sits and differ in what the surrounding positions mean, so the size decodes the same way on both while the refrigerant and efficiency digits do not.
What is specific to Trane
Trane equipment in the decoder
The decoder reads or identifies these Trane lines; each one says what it rests on. Open an example to see the decoder's full answer for it.
| Line | Example model | What the decoder reads | Document |
|---|---|---|---|
| Trane legacy split outdoor unit | 4TWV0036A1000AA | 3 tons (36,000 BTU/h) | 22-1746-04, 22-1725-04, 22-1904-1M-EN |
| Trane R-454B split outdoor unit | 5TTR5024A1000AA | 2 tons (24,000 BTU/h) | 22-8301-39 |
| Trane R-454B Low Profile outdoor unit | 5HPL5036A1000AA | 3 tons (36,000 BTU/h) | 22-8301-39, ODR-PSD038A-EN, DLR-PSD004A-EN |
| RunTru by Trane outdoor unit | A5AC3024B1000 | 2 tons (24,000 BTU/h) | 22-8301-39 |
| Trane ProSpace PTAC (PTEF/PTHF) | PTEF0702GAA | A Trane packaged terminal unit (PTAC or PTHP): its legend prints this code in BTU/h, not a whole, half or quarter ton, so no tonnage is published | PTAC-SVX002A-EN |
| Trane split system (1996 nomenclature, Pub. 22-1633-04) | TWN018C100B | 1.5 tons (18,000 BTU/h), an estimate | Pub. No. 22-1633-04-1296 (EN) |
| Trane RTAC air-cooled Series R chiller | RTAC140 | An air-cooled rotary chiller: large commercial equipment, outside this tool's range, so no tonnage is read | RLC-PRC006M-EN |
| Trane Horizon outdoor air unit (OAD, OAN) | OAND360 | A dedicated outdoor air unit: large commercial equipment, outside this tool's range, so no tonnage is read | OAU-PRC008A-EN |
| Trane air handler (1996 nomenclature, Pub. 22-1633-04) | TWV018B14 | An air handler: identified; its maker's document prints no model number legend, so no size is read | Pub. No. 22-1633-04-1296 (EN) |
| Trane indoor coil (1996 nomenclature, Pub. 22-1633-04) | TXC031E5 | An indoor coil: identified; its maker's document prints no model number legend, so no size is read | Pub. No. 22-1633-04-1296 (EN) |
- Trane Precedent packaged rooftop (3 to 10 tons): packaged or light commercial; its capacity is read from the maker's own printed legend or table, for the codes it prints.
- Trane Precedent packaged rooftop, R-410A J and R-454B K (3 to 25 tons): packaged or light commercial; its capacity is read from the maker's own printed legend or table, for the codes it prints.
- Trane Foundation packaged rooftop (3 to 25 tons): packaged or light commercial; its capacity is read from the maker's own printed legend or table, for the codes it prints.
- Trane Precedent packaged heat pump, R-410A WSC (3 to 10 tons): packaged or light commercial; its capacity is read from the maker's own printed legend or table, for the codes it prints.
- Trane Voyager packaged rooftop (12.5 to 25 tons): packaged or light commercial; its capacity is read from the maker's own printed legend or table, for the codes it prints.
CPSC recall notices naming Trane
Hazard, in the notice's words: “The fuel gas valve can open unexpectedly, allowing a gas leak and posing a fire hazard.”
Hazard, in the notice's words: “The ground wire in the furnace’s junction box can become loose. If an electrical component then fails and short circuits, the unit poses a shock hazard.”
Hazard, in the notice's words: “The ground screws used in some units do not have the two threads required to provide sufficient grounding, posing a shock hazard to consumers.”
Hazard, in the notice's words: “A gas leak can occur if there is a crack in the gas valve body near the inlet pipe connection. A build-up of gas in the burner compartment of the unit could occur, which could be ignited by an internal spark.”
Whether a particular unit is inside a recall depends on the models and serials the notice lists. The Trane serial number lookup checks a unit against the notices.
American Standard, same family as Trane
American Standard is in Trane's family. These are American Standard's lines; each one says what it rests on.
| Line | Example model | What the decoder reads | Document |
|---|---|---|---|
| American Standard split outdoor unit | 4A7A4036B1000AA | 3 tons (36,000 BTU/h) | 12-1173-03, 12-1175-03 |
| American Standard R-454B split outdoor unit | 5A7A4024A1000AA | 2 tons (24,000 BTU/h) | 14-1011-43 |
Other CPSC recall notices naming American Standard
Notices that also name Trane are listed above.
Hazard, in the notice's words: “Heat exchangers in the furnace can crack.”
Whether a particular unit is inside a recall depends on the models and serials the notice lists. The American Standard serial number lookup checks a unit against the notices.
The Trane documents behind this page
Published by trane.com. Fetched 2026-07-24. Covers the R-410A position layout, from a Model Nomenclature diagram that numbers its own positions 1-15: position 5 Family SEER (printing 0 = 20), position 6 Split System Connections (0 = Brazed), positions 7-8 Nominal Capacity in 000s of BTUs.
Published by elibrary.tranetechnologies.com. Fetched 2026-10-01. Covers the legacy outdoor model nomenclature on p6, whose Family SEER prints 0 = 10, 1 = 11 and 2 = 12 beside Refrigerant Type 2 = R-22, 4 = R-410A.
Published by elibrary.tranetechnologies.com. Fetched 2026-10-01. Covers the legacy outdoor model nomenclature on p6, printing the same Family SEER (0 = 10) and Refrigerant Type lines as 22-1746-04.
Published by elibrary.tranetechnologies.com. Fetched 2026-07-24. Covers the explicit Digit 7, 8 Nominal Tonnage table, including every code the divide-by-12 rule gets wrong. The table is Trane's shared capacity table and this tool applies it to both generations; this document itself is an R-454B sheet.
Published by elibrary.tranetechnologies.com. Fetched 2026-10-01. Covers NOM-1 on p15: the R-454B outdoor layout for Trane-branded units (System Type C Cold Climate Heat Pump, T AC, W HP; Nominal Rated SEER2 0 and 3 to 8; Field Connection 0 Brazed, 5 Mechanical; Nominal Tonnage 12 to 72) and the Low Profile layout (HP, HC; SEER2 0 and 3 to 9); RTNOM-1 on p272 and its product rows for RunTru by Trane.
Published by elibrary.tranetechnologies.com. Fetched 2026-07-24. Covers the R-454B system-type letters and the Digit 5 Nominal Rated SEER2 map, for heat pumps. Its capacity table is the same manufacturer boilerplate as the sheet above rather than an independent second reading of it.
American Standard's own documents, listed here because American Standard models share this nomenclature
Published by www.asdealernet.com. Fetched 2026-10-11. Covers American Standard's Outdoor Units model nomenclature on p6: Refrigerant Type 2 = R-22, 4 = R-410A; position 2 AMERICAN STANDARD; Product Type 6 = Split Heat Pump, 7 = Split Cooling; Family SEER 0 = 10 to 9 = 19; Split System Connections 1-6 Tons 0 = Brazed; Nominal Capacity in 000s of BTUs at positions 7-8.
Published by www.asdealernet.com. Fetched 2026-10-11. Covers the same Outdoor Units model nomenclature as 12-1173-03, on p6.
Published by americanstandardair.com. This is a distributor's copy, served from the distributor host of Denver Winair Co., which American Standard lists as a distributor. Fetched 2026-10-12. Covers American Standard's Model Nomenclature Residential - Outdoor on p12 (NOM-1): Refrigerant Type 5 = R-454B; Brand A = American Standard; System Type 5 = Cold Climate HP, 6 = HP, 7 = AC; Product Family A = Silver/Gold AC, C = Light Commercial, H = Silver/Gold HP, V = Platinum VSPD; Nominal Rated SEER2; Field Connection 0 = Brazed, 5 = Mechanical straight fitting; Nominal Tonnage 12 = 1.0 to 61 = 5.0 at positions 7-8.
Frequently asked questions
How do I find the tonnage of a Trane unit from the model number?
Read the capacity code: on Trane it sits at positions 7-8. Position 6 is the field-connection digit, not part of the capacity, and position 1 is the refrigerant. On 4TTR4036N1000 that code is 36, which is 36,000 BTU/h, or 3 tons, because one ton of cooling is 12,000 BTU/h. Use the OUTDOOR unit's model number for system cooling capacity; the indoor air handler or coil carries its own number. This position comes from Trane's own 22-1904-1M-EN, not from a third-party chart.
Can I just divide the Trane capacity code by 12?
Not on every code. Trane prints 7 capacity codes where that division gives the wrong answer: 19 is 1.5 tons where dividing gives 1.58, 25 is 2 tons where dividing gives 2.08, 31 is 2.5 tons where dividing gives 2.58, 37 is 3 tons where dividing gives 3.08, 43 is 3.5 tons where dividing gives 3.58, 49 is 4 tons where dividing gives 4.08, 61 is 5 tons where dividing gives 5.08. Those values come from Trane's own printed table rather than from arithmetic, which is the whole reason the table exists. On every other code in the table the division does work.
Where is the model number on a Trane unit?
On the data plate on the outdoor unit's side panel, labeled M/N or MODEL, usually directly above the serial number. It is labeled M/N, MODEL or MODEL NO., usually printed directly above or beside the serial number. The model number describes what the unit is, including its capacity. The serial number describes when it was built and carries no capacity information at all.
Which Trane document is this based on?
Product Data 4TTR4-L Split System Air Conditioner (22-1904-1M-EN, April 2020), published by trane.com and fetched 2026-07-24, which covers the R-410A position layout, from a Model Nomenclature diagram that numbers its own positions 1-15: position 5 Family SEER (printing 0 = 20), position 6 Split System Connections (0 = Brazed), positions 7-8 Nominal Capacity in 000s of BTUs. Split System Cooling Product & Performance Data XL19i (22-1746-04, 04/09), published by elibrary.tranetechnologies.com and fetched 2026-10-01, which covers the legacy outdoor model nomenclature on p6, whose Family SEER prints 0 = 10, 1 = 11 and 2 = 12 beside Refrigerant Type 2 = R-22, 4 = R-410A. Split System Heat Pump Product Data (22-1725-04, 02/10), published by elibrary.tranetechnologies.com and fetched 2026-10-01, which covers the legacy outdoor model nomenclature on p6, printing the same Family SEER (0 = 10) and Refrigerant Type lines as 22-1746-04. Product and Submittal Data, Outdoor Unit 5HCL9 (DLR-PSD004A-EN, February 2026), published by elibrary.tranetechnologies.com and fetched 2026-07-24, which covers the explicit Digit 7, 8 Nominal Tonnage table, including every code the divide-by-12 rule gets wrong. The table is Trane's shared capacity table and this tool applies it to both generations; this document itself is an R-454B sheet. 2026 Residential and Light Commercial Product Handbook (22-8301-39, Effective 1/1/26), published by elibrary.tranetechnologies.com and fetched 2026-10-01, which covers NOM-1 on p15: the R-454B outdoor layout for Trane-branded units (System Type C Cold Climate Heat Pump, T AC, W HP; Nominal Rated SEER2 0 and 3 to 8; Field Connection 0 Brazed, 5 Mechanical; Nominal Tonnage 12 to 72) and the Low Profile layout (HP, HC; SEER2 0 and 3 to 9); RTNOM-1 on p272 and its product rows for RunTru by Trane. Inverter Side Discharge Heat Pump 5HCL5 (ODR-PSD038A-EN, December 2025), published by elibrary.tranetechnologies.com and fetched 2026-07-24, which covers the R-454B system-type letters and the Digit 5 Nominal Rated SEER2 map, for heat pumps. Its capacity table is the same manufacturer boilerplate as the sheet above rather than an independent second reading of it. Also listed, as American Standard's own and not Trane's: SPLIT SYSTEM COOLING MODELS 4A7A4018-24C/30-060B (12-1173-03, May 2008), published by www.asdealernet.com and fetched 2026-10-11, which covers American Standard's Outdoor Units model nomenclature on p6: Refrigerant Type 2 = R-22, 4 = R-410A; position 2 AMERICAN STANDARD; Product Type 6 = Split Heat Pump, 7 = Split Cooling; Family SEER 0 = 10 to 9 = 19; Split System Connections 1-6 Tons 0 = Brazed; Nominal Capacity in 000s of BTUs at positions 7-8. SPLIT SYSTEM HEAT PUMP MODELS 4A6H4018-060B (12-1175-03, June 2008), published by www.asdealernet.com and fetched 2026-10-11, which covers the same Outdoor Units model nomenclature as 12-1173-03, on p6. 2026 RESIDENTIAL & LIGHT COMMERCIAL PRODUCT HANDBOOK (14-1011-43, Effective 1/1/26 (page 12, NOM-1)), published by americanstandardair.com (a distributor's copy, served from the distributor host of Denver Winair Co., which American Standard lists as a distributor) and fetched 2026-10-12, which covers American Standard's Model Nomenclature Residential - Outdoor on p12 (NOM-1): Refrigerant Type 5 = R-454B; Brand A = American Standard; System Type 5 = Cold Climate HP, 6 = HP, 7 = AC; Product Family A = Silver/Gold AC, C = Light Commercial, H = Silver/Gold HP, V = Platinum VSPD; Nominal Rated SEER2; Field Connection 0 = Brazed, 5 = Mechanical straight fitting; Nominal Tonnage 12 = 1.0 to 61 = 5.0 at positions 7-8. Every capacity value in the capacity tables above traces to one of those documents, and each is named with the date it was fetched so you can pull it yourself. The sizes in the equipment table are read from the document named in its Document column, listed on this page's source receipt.
Is the decoded tonnage the size I should install?
No. Nominal tonnage is what the unit was built to deliver, not what the building needs, and the old unit may have been oversized or sized before insulation and window changes. Treat it as a starting clue and run a load calculation before matching a replacement. Actual delivered capacity also depends on the matched indoor unit, line set, airflow and conditions.
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Got a central system's tonnage? Check it against the house's load.
The old unit's nominal size is a clue, not a load calculation. Oversized systems short-cycle and dehumidify poorly. For central equipment that conditions the whole house, run the numbers before you match a replacement. A PTAC, a single package vertical unit, a room air conditioner or one unit of a VRF system conditions a room or a zone, which this load calculator does not size.