This is the indoor ceiling cassette unit only — Carrier model 45MBCAQ36XA3, a 36,000 BTU/h 4-way cassette designed to sit in a drop ceiling and distribute air in four directions. It's for homeowners or contractors building out a matched Carrier ductless system who need the indoor head specified and priced separately from the outdoor condenser, line set, and grille.
The 45MBCAQ36XA3 is a Carrier Performance Series indoor cassette rated at 36,600 Btu/h cooling, built to mount flush in a drop ceiling and distribute conditioned air through a four-way grille pattern. Carrier's published data covers indoor unit performance only; SEER2, HSPF2, and EER2 ratings are system-level figures that depend on which outdoor condenser it's paired with, so no efficiency rating is stated on this indoor-unit listing. 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 45MBCAQ36XA3, 36K Traditional 4-Way Ceiling Cassette (this listing)
- Outdoor condenser: sold separately — not included with this listing
- Decorative grille panel: sold separately — required for finished installation, not included
- Ceiling mounting/panel sleeve and drain components: sold separately — not included
Installation Requirements & Accessories
- Voltage: 208/230V; 1-Phase; 60Hz
- Refrigerant: R-454B (A2L, mildly flammable classification) — professional installation required
- Liquid line: 3/8 in (9.52 mm); Suction line: 3/4 in (19 mm)
- Line set is sold separately — not included with this indoor unit
- Not included: outdoor condenser, decorative grille, ceiling sleeve, wall/remote controller pairing accessories beyond the included wireless remote
- Not compatible with outdoor units outside Carrier's AHRI-matched combinations for the 45MBCA family
- Professional installation by a licensed HVAC contractor is required — this is not a pre-charged DIY unit
Pro-Installer Tip
Flare connections on 3/8 in and 3/4 in lines are the most common source of slow refrigerant loss and callback "no-cool" complaints on cassette installs — a flare nut torqued by feel instead of spec is the usual culprit. Under-torqued or over-torqued flares on R-454B systems lead to leaks that eventually starve the compressor and can trigger low-charge fault codes at the indoor board. Use a digital torque wrench set to the flare manufacturer's spec and verify the joint with an electronic leak detector before insulating. Because R-454B is an A2L mildly flammable refrigerant, EPA Section 608 certification and adherence to A2L handling procedures are mandatory for anyone brazing, evacuating, or charging this system.
Key Benefits
- Four-way airflow pattern distributes conditioned air evenly across a room from a single ceiling location
- Rated sound level as low as 23.5 dBA for quiet operation in occupied spaces
- Four fan-speed options plus Follow Me temperature sensing via the included wireless remote
- Compatible with Puron Advance (R-454B) refrigerant, rated by Carrier at 75% lower global warming potential than legacy refrigerants
- Installs without ductwork, avoiding ceiling tear-out, patching, or repainting
- Works as part of single-zone or multi-zone Carrier ductless configurations
| Spec | Value | Unit |
|---|---|---|
| Cooling Rated Capacity (DOE A2 - 95°F) | 36600 | Btu/h |
| Cooling Rated Capacity (DOE B2 - 82°F) | 37800 | Btu/h |
| Heating Rated Capacity (DOE H12 - 47°F) | 37000 | Btu/h |
| Heating Rated Capacity (DOE H32 - 17°F) | 30600 | Btu/h |
| Heating Rated Capacity (ODE H42 - 5°F) | 37000 | Btu/h |
| SEER2 / HSPF2 / EER2 | Dependent on paired outdoor unit | — |
| Voltage | 208/230;1;60 | V;Ph;Hz |
| Refrigerant Type | R-454B | — |
| Refrigerant Oil | Ester Oil | — |
| Liquid Pipe Size | 3/8 (9.52) | in (mm) |
| Suction Pipe Size | 3/4 (19) | in (mm) |
| Sound Level (as low as) | 23.5 | dBA |
| Indoor Unit Architecture | Traditional 4-Way Ceiling Cassette | — |
| Breaker Size / MCA / MOCP | [NEEDS VERIFICATION] | — |
Note: See "Resources (System Manuals and Warranty)" Tab above for full specifications.
Compatibility & Fitment
- Fits: Carrier 45MBCA family AHRI-matched multi-zone/single-zone outdoor condenser pairings for the 36K size class
- Compatible with dedicated 208/230V single-phase circuits
- This is a Traditional 4-Way Ceiling Cassette — it is NOT a slim one-way cassette and does not fit between standard 16-inch on-center joist bays
- Not compatible with 115V-only circuits
- Outdoor condenser is NOT included and must be purchased separately as an AHRI-matched pairing
- Line set is NOT included — size per this unit is 3/8 in liquid / 3/4 in suction
- Decorative grille panel and ceiling mounting sleeve are NOT included
FAQ
What breaker size do I need for this system?
[NEEDS VERIFICATION] — breaker size (MOCP) is set by the outdoor unit's electrical data table, not the indoor cassette. Refer to the outdoor unit's nameplate and installation instructions once it is selected.
Is professional installation required to keep the warranty valid, or is this a true DIY kit?
This is not a DIY kit. This unit uses R-454B (A2L) refrigerant and requires professional installation by a licensed HVAC contractor to keep the warranty valid.
Is the line set included, and if not, what size do I need to buy?
The line set is sold separately. This indoor unit uses a 3/8 inch liquid line and a 3/4 inch suction line.
Will the ceiling cassette fit between standard 16-inch on-center joists?
No. This is a Traditional 4-Way Ceiling Cassette, designed for a drop/suspended ceiling installation with a separate decorative grille, not a slim one-way cassette built for standard 16-inch on-center joist bays.
Does this system work in cold climates (low-ambient heating)?
Heating capacity for this indoor unit is rated at 37,000 Btu/h at 47°F (DOE H12) and 30,600 Btu/h at 17°F (DOE H32). Low-ambient heating performance depends on which outdoor unit it is paired with.
Compliance & Warranty
This unit uses R-454B (A2L) refrigerant. Installation by a licensed HVAC professional is required to maintain warranty. 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. Confirm exact terms and registration deadlines in the manufacturer warranty documentation referenced in the Resources tab.
