Carrier: what you can keep on an A2L swap

Checked against Carrier Puron Advance — FAQ Document, September 2026.

Carrier sells its A2L equipment as Puron Advance (R-454B), and its public FAQ is unusual: it answers all three swap questions in one document — the refrigerant, the line set and the indoor coil — and it answers the gas furnace question too, which most brands do not. That is why Carrier is the first brand on this site.

Indoor coil

Has to be replaced

Your 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.

Line set

Can stay, with conditions

Your 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.

Furnace

Can stay

Your 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.

What to ask your installer about any Carrier swap

Which indoor coil are you fitting, and what is the AHRI certified reference number for that combination?
Are you reusing my line set, and how will you prove it is clean and holds a pressure test?

The documents behind this

ManufacturerPuron Advance is not a drop-in replacement for R-410A. The pressures and temperatures are close, but new compressors and expansion devices are still required for ideal operation, and Carrier concludes that R-454B should not be used in R-410A systems.

Carrier — Carrier Puron Advance — FAQ Document (prod_R454B_FAQ_car1). Read 2026-09-01.

ManufacturerFull furnace coils are not interchangeable between refrigerants: the refrigerant the indoor coil is designed for must match the outdoor unit's. Carrier's Replacement Components division offers replacement coils that can replace either an R-410A or an R-454B coil, for repairs.

Carrier — Carrier Puron Advance — FAQ Document (prod_R454B_FAQ_car1). Read 2026-09-01.

ManufacturerLine sets can be reused as long as they continue to meet local building codes. Carrier says there is no need to replace them from a system standpoint, because R-454B uses POE oil as R-410A does.

Carrier — Carrier Puron Advance — FAQ Document (prod_R454B_FAQ_car1). Read 2026-09-01.

ManufacturerLocal building codes regulate what is needed for refrigerant runs, and fire breaks are required in high-rise buildings. Carrier repeats that a line set need not be replaced for R-454B as long as it meets the current building code.

Carrier — Carrier Puron Advance — FAQ Document (prod_R454B_FAQ_car1). Read 2026-09-01.

ManufacturerAsked whether an existing gas furnace must be replaced when a split system is replaced with R-454B, Carrier answers that the dissipation control intercepts the thermostat signal and changes the inputs to the furnace when dissipation is needed. The furnace does not operate differently from its design, and no extra add-on items are needed to modify it.

Carrier — Carrier Puron Advance — FAQ Document (prod_R454B_FAQ_car1). Read 2026-09-01.

Our readingCarrier's answer is about the furnace itself. It does not say that the rest of the installation needs nothing, and it does not name the equipment the dissipation control ships in — so the furnace staying is not the same as the job needing no mitigation hardware anywhere.

Follows from the claims above on this page.

ManufacturerAll Carrier fan coils ship with a full leak detection system already installed in the equipment. The question Carrier was answering was about fan coils, and the answer names no other kind of indoor unit — so this site does not read it as covering furnace coils.

Carrier — Carrier Puron Advance — FAQ Document (prod_R454B_FAQ_car1). Read 2026-09-01.

ManufacturerCarrier equipment cannot be used for both refrigerants. Carrier said it was investigating a conversion kit to allow a change from R-410A to R-454B; no such kit is named in the document.

Carrier — Carrier Puron Advance — FAQ Document (prod_R454B_FAQ_car1). Read 2026-09-01.

ManufacturerMechanical fittings are standard on all Carrier R-454B equipment, and service gauges do not need reverse threads — a thread adaptor is needed for the refrigerant cylinder only.

Carrier — Carrier Puron Advance — FAQ Document (prod_R454B_FAQ_car1). Read 2026-09-01.

ManufacturerCarrier describes Puron Advance as mildly flammable rather than explosive: it can only ignite at concentrations in air between a lower flammability limit of 11.3% and an upper limit of 23.6%. Carrier adds that refrigerant left absorbed in the oil cannot reach those concentrations.

Carrier — Carrier Puron Advance — FAQ Document (prod_R454B_FAQ_car1). Read 2026-09-01.

ManufacturerR-454B contains no propane. Carrier describes it as a blend, like R-410A, of 68.9% R-32 and 31.1% R-1234yf.

Carrier — Carrier Puron Advance — FAQ Document (prod_R454B_FAQ_car1). Read 2026-09-01.

What replaces what: the Carrier A2L range

Every Carrier A2L outdoor unit on this site, and the R-410A model it replaces. This is the table that today exists only inside a PDF. The last column says which document each row was read from; a model links to its own page once a document about that model has been read.

A2L model	Type	Tier	Compressor	Region	Replaces	Data read
26SCA4	Air conditioner	Comfort	single-stage	North only	24SCA4, 24ABB3	transition guide, spec sheet
26SCA5	Air conditioner	Comfort	single-stage	All	24SCA5	transition guide only
26SPA6	Air conditioner	Performance	single-stage	All	24SPA6	transition guide only
26TPA8	Air conditioner	Performance	two-stage	All	24TP(A/B)7	transition guide only
26VNA1	Air conditioner	Infinity	variable-speed	All	24VNA9	transition guide only
GA4SAN5	Air conditioner	Builder	single-stage	North only	GA4SAN4	transition guide only
GA5SAN5	Air conditioner	Builder	single-stage	All	GA5SAN4	transition guide only
GA8TAN5	Air conditioner	Builder	two-stage	All	GA7TAN4	transition guide only
27SCA5	Heat pump	Comfort	single-stage	All	25SCA5, 25HCE4	transition guide only
27SPA6	Heat pump	Performance	single-stage	All	25SPA5	transition guide only
27TPA8	Heat pump	Performance	two-stage	All	25TP(A,B)7	transition guide only
27VNA0	Heat pump	Infinity	variable-speed	All	25VNA8	transition guide only
27VNA1	Heat pump	Infinity	variable-speed	North only	—	transition guide only
27VNA3	Heat pump	Infinity	variable-speed	All	25VNA4	transition guide only
37MUHAQ	Heat pump	Performance	variable-speed	All	38MURAQ**AB3	transition guide only
37MURAQ	Heat pump	Comfort	variable-speed	All	38MURAQ**AA3	transition guide only
GH5SAN5	Heat pump	Builder	single-stage	All	GH5SAN4	transition guide only
GH8TAN5	Heat pump	Builder	two-stage	All	GH7TAN4	transition guide only

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.