Carrier 26SCA4
Checked against 26SCA4 Comfort Series Single-Stage Air Conditioner with Puron Advance Refrigerant — Product Data, September 2026.
Air conditioner on R-454B, 1.5 to 5 ton. Here is what the Carrier documents say you can keep.
26SCA4 is a model family. The data plate on your
unit carries a longer number that starts with 26SCA4 — the size
and revision digits follow it. This page covers the family.
The bulletin lists these model numbers in it: 26SCA418N003 , 26SCA424N003 , 26SCA430N003 , 26SCA436N003 , 26SCA436N005 , 26SCA436N006 , 26SCA436N001 , 26SCA442N003 , 26SCA448N013 , 26SCA448N005 , 26SCA448N006 , 26SCA448N001 , 26SCA460N003 , 26SCA460N005 , 26SCA460N006 , 26SCA460N001 .
Indoor coil
Has to be replacedYour existing R-410A indoor coil cannot stay. Carrier states that full furnace coils are not interchangeable and that the refrigerant the indoor coil is designed for must match the outdoor unit's.
Not checked: your own coil against this unit. That needs its model number, which is on the coil label inside the air handler or furnace cabinet.
Carrier's brand rule — see the brand page.Line set
Can stay, with conditionsYour copper can normally stay. Carrier says there is no system-side reason to replace a line set, because R-454B uses the same POE oil as R-410A — but it puts the decision under your building code.
- The line set continues to meet the local building code in force, which is what Carrier makes the reuse conditional on.
- In high-rise buildings, Carrier states that fire breaks will be required on the refrigerant run.
Not checked: your line size. The 26SCA4 uses 3/8" liquid with 5/8" or 3/4" or 7/8" or 1-1/8" suction, by capacity, and you have not measured the outside diameter of both copper lines.
Carrier's brand rule — see the brand page.Furnace
Can stayYour existing gas furnace does not have to be replaced and needs no add-on kit. Carrier states that the dissipation control intercepts the signal from the thermostat and the furnace otherwise operates exactly as designed.
Carrier's brand rule — see the brand page.Check your own coil and line set →
Sizes and line diameters
From the 26SCA4 product data, size by size.
| Model | Capacity | Liquid line OD | Suction line OD |
|---|---|---|---|
26SCA418 | 1.5 ton | 3/8" | 5/8" |
26SCA424 | 2 ton | 3/8" | 3/4" |
26SCA430 | 2.5 ton | 3/8" | 3/4" |
26SCA436 | 3 ton | 3/8" | 7/8" |
26SCA442 | 3.5 ton | 3/8" | 7/8" |
26SCA448 | 4 ton | 3/8" | 7/8" |
26SCA460 | 5 ton | 3/8" | 1-1/8" |
How Carrier lists this unit
| Tier | Comfort |
|---|---|
| Compressor | single-stage |
| Region | Northern efficiency region only |
| Coastal option | Not listed |
Also listed as the replacement for the three-phase Comfort 24ABB3. The product data sheet rates the family at 13.4 to 16.0 SEER2 and 11.0 to 13.5 EER2, depending on capacity and the indoor unit it is matched with.
What the documents say about this model
ManufacturerCarrier's product data sheet gives the rated refrigerant tube outside diameters for each capacity in the family. The liquid line is 3/8 inch at every size. The vapour line is 5/8 inch at 1.5 tons, 3/4 inch at 2 and 2.5 tons, 7/8 inch at 3, 3.5 and 4 tons, and 1-1/8 inch at 5 tons. The sheet notes that these ratings assume 25 feet of line set and points to its own sizing tables for other lengths.
ManufacturerThe family is rated for a total equivalent line length of up to 250 feet. The vertical separation limit differs by direction: up to 200 feet with the condenser above the evaporator, or up to 80 feet with the evaporator above the condenser. Carrier points to its Long Line Guide beyond that.
ManufacturerA filter drier is supplied with the unit and installed in the field, on every capacity in the family. It is listed as a feature of all seven sizes rather than as an accessory.
ManufacturerThe 250 foot figure assumes a 3/8 inch liquid line. The sheet's own table shows how far the run may go with a smaller line and with the outdoor unit below the indoor one, and the numbers fall away quickly: at 1.5 tons a 1/4 inch liquid line is limited to 150 feet with almost no vertical separation and is outside the acceptable range past 50 feet of it. At 5 tons, even a 3/8 inch line drops to 110 feet once the vertical separation reaches 51 to 60 feet, and is not listed beyond 70.
The rest of the answer above is Carrier's brand-wide rule — 9 cited statements, written out in full on the Carrier rules page.
Approved and certified combinations
We have not yet read a published match list for this unit. Ask your installer for the AHRI certified reference number of the combination they are quoting — every certified pair has one.
What this unit replaces
The 26SCA4 is the R-454B successor to 24SCA4, 24ABB3. If that is what is on the pad today, this is the unit being quoted to you.
What to ask your installer about the 26SCA4
- The 26SCA4 takes 3/8" liquid with 5/8" or 3/4" or 7/8" or 1-1/8" suction, by capacity. Which capacity are you quoting me, and does my existing copper match the diameters for it?
The questions to ask about any Carrier swap are on the Carrier rules page.
Questions people ask about this unit
What line size does the 26SCA4 need?
The liquid line is 3/8 inch at every capacity. The vapour line depends on the size: 5/8 inch at 1.5 tons, 3/4 inch at 2 and 2.5 tons, 7/8 inch at 3, 3.5 and 4 tons, and 1-1/8 inch at 5 tons. The table on this page is read from Carrier's product data sheet for this family.
How long can the line set be on a 26SCA4?
Up to 250 total equivalent feet with a 3/8 inch liquid line, but the vertical separation between the two units matters as much as the length, and the limit falls sharply on the larger sizes. Carrier's own table is summarised in the citations below, and its Long Line Guide covers the rest.
Other Carrier air conditioners
| Model | Tier | Compressor | Replaces |
|---|---|---|---|
| 26SPA6 | Performance | single-stage | 24SPA6 |
| 26SCA5 | Comfort | single-stage | 24SCA5 |
| 26TPA8 | Performance | two-stage | 24TP(A/B)7 |
| 26VNA1 | Infinity | variable-speed | 24VNA9 |
| GA4SAN5 | Builder | single-stage | GA4SAN4 |
| GA5SAN5 | Builder | single-stage | GA5SAN4 |
Read next
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.