This is a Carrier 12K BTU/h one-way ceiling cassette indoor unit, sold as the indoor component only. It's built for homeowners or contractors assembling a single- or multi-zone ductless system who need a low-profile cassette that fits between standard ceiling joists rather than a wall-mounted head.
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.
This 45MCCA-family cassette is engineered to sit flush in a finished ceiling, with a slim body that fits between standard 16-inch on-center joists — no drop-ceiling required. It pairs with single- or multi-zone Carrier outdoor condensers under AHRI-certified system combinations. Overall system SEER2/HSPF2/EER2 ratings depend entirely on which outdoor unit it's matched with; those numbers are not assigned to the indoor cassette alone.
System Components
- Indoor Unit: Carrier 45MCCAQ12XA3, 12K BTU/h one-way ceiling cassette (this listing)
- Outdoor Condenser: sold separately — must be selected as an AHRI-matched pairing; not included with this listing
Installation Requirements & Accessories
- Voltage: 208/230V; 1Ph; 60Hz (system-level power supply per manufacturer data)
- Refrigerant: R-454B (Puron Advance), an A2L mildly flammable classification
- Line Set Sold Separately — liquid/suction sizing must match the specific paired outdoor unit
- Ceiling grille, mounting frame/sleeve, and wireless remote hardware sold separately unless explicitly listed elsewhere
- Not compatible with 115V-only circuits
- Not included: outdoor condenser, line set, grille, mounting sleeve/frame kit
- Professional installation by a licensed HVAC contractor is required — this is not a DIY unit
Pro-Installer Tip
Flare connections on A2L refrigerant systems like this R-454B cassette leave no room for shortcuts. A flare nut torqued below spec, or a flare face nicked during cutting, becomes a slow leak that shows up months later as reduced capacity or a communication fault between indoor and outdoor boards. Evacuate the line set properly and confirm the joint with a digital torque wrench set to the fitting's rated spec before charging. Because R-454B is a mildly flammable A2L refrigerant, EPA Section 608 certification covering A2L handling procedures is required for anyone brazing, evacuating, or charging this system.
Key Benefits
- Slim cassette body fits between standard 16-inch on-center joists — no drop-ceiling needed
- Compatible with single- and multi-zone Carrier outdoor systems
- Follow Me function with temperature-sensing wireless remote and four fan speeds
- Sound level as low as 23.5 decibels (across the 45MCCA size range, per manufacturer data)
- Puron Advance (R-454B) refrigerant — 75% lower global warming potential than traditional refrigerants, non-ozone-depleting
| Spec | Value | Unit |
|---|---|---|
| Component Role | Indoor Cassette Unit Only | — |
| Model | 45MCCAQ12XA3 | — |
| Indoor Unit Architecture | Slim One-Way Ceiling Cassette | — |
| Cooling Rated Capacity (DOE A2 - 95°F) | 12000 | Btu/h |
| Heating Rated Capacity (DOE H12 - 47°F) | 12500 | Btu/h |
| Power Supply | 208/230V; 1Ph; 60Hz | — |
| Refrigerant Type | R-454B (Puron Advance) | — |
| SEER2 / HSPF2 / EER2 | Dependent on paired outdoor unit | — |
| DIY Status | No — Professional Installation Required | — |
Note: See "Resources (System Manuals and Warranty)" Tab above for full specifications.
Compatibility & Fitment
- Fits standard 16-inch on-center ceiling joist bays as a slim one-way cassette
- Compatible with AHRI-certified single- and multi-zone Carrier outdoor condenser pairings
- Requires a dedicated 208/230V single-phase circuit at the system level — not compatible with 115V-only circuits
- Line set is NOT included — size must be confirmed against the specific paired outdoor unit
- Ceiling grille and mounting sleeve/frame are NOT included with this listing
- Outdoor condenser is NOT included — must be purchased and matched separately
FAQ
What breaker size do I need for this system?
Breaker sizing depends on the paired outdoor condenser, not this indoor cassette alone. [NEEDS VERIFICATION] — check the matched outdoor unit's MCA/MOP rating before sizing the circuit.
Is professional installation required to keep the warranty valid, or is this a true DIY kit?
This is not a DIY kit. It uses R-454B refrigerant (an A2L mildly flammable class) and requires professional installation by a licensed HVAC contractor.
Is the line set included, and if not, what size do I need to buy?
The line set is sold separately. For the matched 12K outdoor system class, published liquid/suction line sizes in the manufacturer data are 1/4 in (6.35mm) liquid and 3/8 in (9.52mm) suction — confirm against your specific paired outdoor model before ordering, since sizes vary by outdoor unit size.
Will the ceiling cassette fit between standard 16-inch on-center joists?
Yes. This is a slim one-way cassette designed to fit between standard 16-inch on-center ceiling joists, avoiding drop-ceiling or major remodeling work.
Does this system work in cold climates (low-ambient heating)?
Low-ambient heating performance is a system-level rating that depends on the paired outdoor unit. [NEEDS VERIFICATION] for this indoor component alone.
Compliance & Warranty
Installation by a licensed HVAC professional is required to maintain warranty. This unit uses R-454B (A2L classification) refrigerant, and installation must comply with EPA Section 608 handling requirements. Carrier's Consumer Choice Warranty offers, upon timely registration on eligible equipment, either a 10-year parts-only limited warranty or a 5-year parts plus 3-year labor limited warranty — refer to the Resources tab for full terms and registration requirements.
