Carrier | 48K BTU | Traditional 4-Way Ceiling Cassette Indoor Unit | 208/230V | 45MBCAQ48XA3

This is a Carrier 48,000 BTU/h indoor ceiling cassette unit — the indoor component only, for use in single or multi-zone ductless systems. It's built for homeowners and installers adding a flush, ceiling-mounted comfort zone to a room, and it requires a matched outdoor condenser, refrigerant line set, and grille kit that are not part of this listing.

Carrier's Performance Series 4-way cassette is engineered to mount flush into a standard drop ceiling, distributing conditioned air in four directions from a central grille rather than through joist bays. It's AHRI-certified as part of matched system combinations with Carrier outdoor condensers. Note: If you would like to review the manufacturer Product Specifications, Warranty, Brochure, etc., for this system, please refer to the "Resources (System Manuals and Warranty)" Tab above on this page.

System Components

• Indoor unit: Carrier 45MBCAQ48XA3, 48K BTU/h 4-way ceiling cassette (this listing)
• Decorative grille: sold separately, not included with this SKU
• Outdoor condenser: sold separately — must be a Carrier-matched, AHRI-certified pairing (e.g., 37MBHAQ family, per capacity)

Installation Requirements & Accessories

• Voltage: 208/230V; 1Ph; 60Hz
• Refrigerant: R-454B (A2L, mildly flammable classification) — professional installation required
• Liquid line: 3/8 in (9.52mm); Suction line: 3/4 in (19mm)
• Line set sold separately — not included with this indoor unit
• Decorative grille sold separately — not included with this indoor unit
• Mounting/ceiling sleeve and hardware not included where applicable
• Not compatible with 115V-only circuits
• Not a stand-alone system — not compatible with non-Carrier outdoor units outside AHRI-matched combinations

Pro-Installer Tip

Flare connections on 3/8 in and 3/4 in lines are common points of refrigerant loss if over- or under-torqued — this is especially important on R-454B (A2L) systems, where leak-tightness has direct safety implications given the refrigerant's mild flammability classification. Undertightened flares lead to slow refrigerant bleed-down, reduced capacity, and nuisance fault codes over time. Confirm every flare joint with a calibrated digital torque wrench set to the manufacturer's spec rather than "feel." This work falls under EPA Section 608 certification requirements for handling R-454B refrigerant, and proper flare technique protects both the system's rated efficiency and the technician's certification standing.

Key Benefits

• Inverter-driven compressor pairing (via matched outdoor unit) for variable-speed comfort rather than on/off cycling
• Sound levels as low as 23.5 dBA for a quiet overhead installation
• Four fan-speed options with Follow Me temperature sensing via the included wireless remote
• Compatible with Puron Advance™ (R-454B) refrigerant, rated to reduce global warming potential by 75% versus traditional refrigerants
• Installs without ductwork, avoiding ceiling tear-out, patching, or repainting
• Works across single-zone and multi-zone system configurations

Note: See "Resources (System Manuals and Warranty)" Tab above for full specifications.

Compatibility & Fitment

• Fits into a standard drop-ceiling grid as a 4-way cassette; this is NOT a slim one-way cassette designed for 16-inch on-center joist bays.
• Must be paired with a matched, AHRI-certified Carrier outdoor condenser (e.g., 37MBHAQ48AA3 for this 48K size) to operate — this listing does not include the outdoor unit.
• Requires a 208/230V, 1-phase, 60Hz circuit. Not compatible with 115V-only circuits.
• Line set (3/8 in liquid / 3/4 in suction) is sold separately and is not included with this SKU.
• Decorative grille, ceiling sleeve/mounting hardware are not included and must be ordered separately.

FAQ

Is professional installation required to keep the warranty valid, or is this a true DIY kit?

Professional installation is required. This unit uses R-454B (A2L) refrigerant and is not a pre-charged DIY kit.

Is the line set included, and if not, what size do I need to buy?

The line set is sold separately. This model requires a 3/8 in (9.52mm) liquid line and a 3/4 in (19mm) suction line.

Will the ceiling cassette fit between standard 16-inch on-center joists?

This is a traditional 4-way cassette designed for a drop-ceiling grid, not a slim one-way cassette built for 16-inch on-center joist bays. [NEEDS VERIFICATION] for exact cutout dimensions — refer to the manufacturer specification sheet.

What breaker size do I need for this system?

[NEEDS VERIFICATION] — breaker size (MCA/MOCP) depends on the paired outdoor unit and is not specified for the indoor cassette alone in the manufacturer data provided.

Does this system work in cold climates (low-ambient heating)?

Heating performance depends on the paired outdoor unit. Published heating capacity at 5°F for this indoor size is 47,500 BTU/h when matched with a compatible Carrier outdoor unit.

Compliance & Warranty

Installation by a licensed HVAC professional is required to maintain warranty. This unit uses R-454B (A2L) refrigerant, and installation must comply with EPA Section 608 handling requirements and local electrical and building codes. Carrier's Consumer Choice Warranty applies upon timely registration on eligible equipment: choose either a 10-year parts-only limited warranty or a 5-year parts plus 3-year labor limited warranty. Ask us before you order if you're unsure which outdoor unit pairing keeps this cassette AHRI-certified for your capacity needs — we always reply back.