Line set sizes, model by model
Whether your copper can stay is two questions, and only the second one is about rules. The first is arithmetic: what diameter is already in the wall, and what diameter does the unit you were quoted call for? This table is the arithmetic. Every row is read from that model's own product data sheet and nothing is carried over from a sibling model.
132 units, 21 families
Liquid line first, because it is the one that almost never changes: it is 3/8 inch on every unit read so far. The suction line is what moves with capacity, and it is where a reused line set stops fitting.
| Model | Refrigerant | Capacity | Liquid line OD | Suction line OD |
|---|---|---|---|---|
| 24ABB318 | R-410A | 1.5 ton | 3/8" | 3/4" |
| 24ABB324 | R-410A | 2 ton | 3/8" | 3/4" |
| 24ABB330 | R-410A | 2.5 ton | 3/8" | 3/4" |
| 24ABB336 | R-410A | 3 ton | 3/8" | 7/8" |
| 24ABB342 | R-410A | 3.5 ton | 3/8" | 7/8" |
| 24ABB348 | R-410A | 4 ton | 3/8" | 7/8" |
| 24ABB360 | R-410A | 5 ton | 3/8" | 1-1/8" |
| 24AHA418 | R-410A | 1.5 ton | 3/8" | 5/8" |
| 24AHA424 | R-410A | 2 ton | 3/8" | 3/4" |
| 24AHA430 | R-410A | 2.5 ton | 3/8" | 3/4" |
| 24AHA436 | R-410A | 3 ton | 3/8" | 7/8" |
| 24AHA448 | R-410A | 4 ton | 3/8" | 7/8" |
| 24AHA460 | R-410A | 5 ton | 3/8" | 1-1/8" |
| 24SCA418 | R-410A | 1.5 ton | 3/8" | 3/4" |
| 24SCA424 | R-410A | 2 ton | 3/8" | 3/4" |
| 24SCA430 | R-410A | 2.5 ton | 3/8" | 3/4" |
| 24SCA436 | R-410A | 3 ton | 3/8" | 7/8" |
| 24SCA442 | R-410A | 3.5 ton | 3/8" | 7/8" |
| 24SCA448 | R-410A | 4 ton | 3/8" | 7/8" |
| 24SCA460 | R-410A | 5 ton | 3/8" | 1-1/8" |
| 24SCA518 | R-410A | 1.5 ton | 3/8" | 3/4" |
| 24SCA524 | R-410A | 2 ton | 3/8" | 3/4" |
| 24SCA530 | R-410A | 2.5 ton | 3/8" | 3/4" |
| 24SCA536 | R-410A | 3 ton | 3/8" | 7/8" |
| 24SCA542 | R-410A | 3.5 ton | 3/8" | 7/8" |
| 24SCA548 | R-410A | 4 ton | 3/8" | 7/8" |
| 24SCA560 | R-410A | 5 ton | 3/8" | 1-1/8" |
| 24SPA618 | R-410A | 1.5 ton | 3/8" | 3/4" |
| 24SPA624 | R-410A | 2 ton | 3/8" | 3/4" |
| 24SPA630 | R-410A | 2.5 ton | 3/8" | 3/4" |
| 24SPA636 | R-410A | 3 ton | 3/8" | 7/8" |
| 24SPA642 | R-410A | 3.5 ton | 3/8" | 7/8" |
| 24SPA643 | R-410A | 3.5 ton | 3/8" | 7/8" |
| 24SPA648 | R-410A | 4 ton | 3/8" | 7/8" |
| 24SPA649 | R-410A | 4 ton | 3/8" | 7/8" |
| 24SPA660 | R-410A | 5 ton | 3/8" | 1-1/8" |
| 24SPA661 | R-410A | 5 ton | 3/8" | 1-1/8" |
| 24VNA624 | R-410A | 2 ton | 3/8" | 3/4" |
| 24VNA636 | R-410A | 3 ton | 3/8" | 7/8" |
| 24VNA648 | R-410A | 4 ton | 3/8" | 1-1/8" |
| 24VNA660 | R-410A | 5 ton | 3/8" | 1-1/8" |
| 24VNA913 | R-410A | 1 ton | 3/8" | 3/4" |
| 24VNA924 | R-410A | 2 ton | 3/8" | 3/4" |
| 24VNA925 | R-410A | 2 ton | 3/8" | 7/8" |
| 24VNA936 | R-410A | 3 ton | 3/8" | 7/8" |
| 24VNA937 | R-410A | 3 ton | 3/8" | 1-1/8" |
| 24VNA948 | R-410A | 4 ton | 3/8" | 1-1/8" |
| 24VNA949 | R-410A | 4 ton | 3/8" | 1-1/8" |
| 24VNA960 | R-410A | 5 ton | 3/8" | 1-1/8" |
| 25HCE418 | R-410A | 1.5 ton | 3/8" | 5/8" |
| 25HCE424 | R-410A | 2 ton | 3/8" | 5/8" |
| 25HCE430 | R-410A | 2.5 ton | 3/8" | 3/4" |
| 25HCE436 | R-410A | 3 ton | 3/8" | 3/4" |
| 25HCE442 | R-410A | 3.5 ton | 3/8" | 7/8" |
| 25HCE448 | R-410A | 4 ton | 3/8" | 7/8" |
| 25HCE460 | R-410A | 5 ton | 3/8" | 1-1/8" |
| 25SCA518 | R-410A | 1.5 ton | 3/8" | 5/8" |
| 25SCA524 | R-410A | 2 ton | 3/8" | 5/8" |
| 25SCA530 | R-410A | 2.5 ton | 3/8" | 3/4" |
| 25SCA536 | R-410A | 3 ton | 3/8" | 3/4" |
| 25SCA542 | R-410A | 3.5 ton | 3/8" | 7/8" |
| 25SCA548 | R-410A | 4 ton | 3/8" | 7/8" |
| 25SCA560 | R-410A | 5 ton | 3/8" | 1-1/8" |
| 25VNA424 | R-410A | 2 ton | 3/8" | 3/4" |
| 25VNA436 | R-410A | 3 ton | 3/8" | 7/8" |
| 25VNA448 | R-410A | 4 ton | 3/8" | 1-1/8" |
| 25VNA460 | R-410A | 5 ton | 3/8" | 1-1/8" |
| 25VNA813 | R-410A | 1 ton | 3/8" | 3/4" |
| 25VNA824B | R-410A | 2 ton | 3/8" | 3/4" |
| 25VNA824A | R-410A | 2 ton | 3/8" | 7/8" |
| 25VNA825 | R-410A | 2 ton | 3/8" | 7/8" |
| 25VNA836 | R-410A | 3 ton | 3/8" | 7/8" |
| 25VNA837 | R-410A | 3 ton | 3/8" | 1-1/8" |
| 25VNA848 | R-410A | 4 ton | 3/8" | 1-1/8" |
| 25VNA860 | R-410A | 5 ton | 3/8" | 1-1/8" |
| 26SCA418 | R-454B | 1.5 ton | 3/8" | 5/8" |
| 26SCA424 | R-454B | 2 ton | 3/8" | 3/4" |
| 26SCA430 | R-454B | 2.5 ton | 3/8" | 3/4" |
| 26SCA436 | R-454B | 3 ton | 3/8" | 7/8" |
| 26SCA442 | R-454B | 3.5 ton | 3/8" | 7/8" |
| 26SCA448 | R-454B | 4 ton | 3/8" | 7/8" |
| 26SCA460 | R-454B | 5 ton | 3/8" | 1-1/8" |
| 26SCA518 | R-454B | 1.5 ton | 3/8" | 5/8" |
| 26SCA524 | R-454B | 2 ton | 3/8" | 3/4" |
| 26SCA530 | R-454B | 2.5 ton | 3/8" | 3/4" |
| 26SCA536 | R-454B | 3 ton | 3/8" | 7/8" |
| 26SCA542 | R-454B | 3.5 ton | 3/8" | 7/8" |
| 26SCA548 | R-454B | 4 ton | 3/8" | 7/8" |
| 26SCA560 | R-454B | 5 ton | 3/8" | 1-1/8" |
| 27SCA518 | R-454B | 1.5 ton | 3/8" | 5/8" |
| 27SCA524 | R-454B | 2 ton | 3/8" | 5/8" |
| 27SCA530 | R-454B | 2.5 ton | 3/8" | 3/4" |
| 27SCA536 | R-454B | 3 ton | 3/8" | 3/4" |
| 27SCA542 | R-454B | 3.5 ton | 3/8" | 7/8" |
| 27SCA548 | R-454B | 4 ton | 3/8" | 7/8" |
| 27SCA560 | R-454B | 5 ton | 3/8" | 1-1/8" |
| 27VNA024 | R-454B | 2 ton | 3/8" | 3/4" |
| 27VNA036 | R-454B | 3 ton | 3/8" | 7/8" |
| 27VNA048 | R-454B | 4 ton | 3/8" | 7/8" |
| 27VNA060 | R-454B | 5 ton | 3/8" | 1-1/8" |
| 27VNA154A003 | R-454B | 4.5 ton | 3/8" | 1-1/8" |
| 27VNA336A003 | R-454B | 3 ton | 3/8" | 7/8" |
| 27VNA348A003 | R-454B | 4 ton | 3/8" | 1-1/8" |
| 27VNA360A003 | R-454B | 5 ton | 3/8" | 1-1/8" |
| 5A6H4018 | R-454B | 1.5 ton | 5/16" | 3/4" |
| 5A6H4024 | R-454B | 2 ton | 5/16" | 3/4" |
| 5A6H4030 | R-454B | 2.5 ton | 5/16" | 3/4" |
| 5A6H4036 | R-454B | 3 ton | 5/16" | 3/4" |
| 5A6H4042 | R-454B | 3.5 ton | 5/16" | 7/8" |
| 5A6H4048 | R-454B | 4 ton | 5/16" | 7/8" |
| 5A6H4060 | R-454B | 5 ton | 5/16" | 7/8" |
| 5A7A3018 | R-454B | 1.5 ton | 5/16" | 3/4" |
| 5A7A3024 | R-454B | 2 ton | 5/16" | 3/4" |
| 5A7A3030 | R-454B | 2.5 ton | 5/16" | 3/4" |
| 5A7A3036 | R-454B | 3 ton | 5/16" | 3/4" |
| 5A7A3042 | R-454B | 3.5 ton | 5/16" | 7/8" |
| 5A7A3048 | R-454B | 4 ton | 5/16" | 7/8" |
| 5A7A3060 | R-454B | 5 ton | 5/16" | 7/8" |
| 5A7A4018 | R-454B | 1.5 ton | 5/16" | 3/4" |
| 5A7A4024 | R-454B | 2 ton | 5/16" | 3/4" |
| 5A7A4030 | R-454B | 2.5 ton | 5/16" | 3/4" |
| 5A7A4036 | R-454B | 3 ton | 5/16" | 7/8" |
| 5A7A4042 | R-454B | 3.5 ton | 5/16" | 7/8" |
| 5A7A4048 | R-454B | 4 ton | 5/16" | 7/8" |
| 5A7A4060 | R-454B | 5 ton | 5/16" | 7/8" |
| 5A7A5018 | R-454B | 1.5 ton | 5/16" | 3/4" |
| 5A7A5024 | R-454B | 2 ton | 5/16" | 3/4" |
| 5A7A5030 | R-454B | 2.5 ton | 5/16" | 3/4" |
| 5A7A5036 | R-454B | 3 ton | 5/16" | 7/8" |
| 5A7A5042 | R-454B | 3.5 ton | 5/16" | 7/8" |
| 5A7A5048 | R-454B | 4 ton | 5/16" | 7/8" |
| 5A7A5060 | R-454B | 5 ton | 5/16" | 1-1/8" |
A model number links to its page where the family has one. Where it does not, the family is a row in its brand table and the diameters above are still what its manufacturer published.
The rules that go with the numbers
This is a starting point, not an approval. Everything here is read from published manufacturer documents and dated, but only the licensed contractor who signs your installation can approve a specific system for your home and your local code. Take the citations on this page to them and ask.