MRCOOL Olympus Multi-Zone 4th Gen — Ceiling Cassette System (Professional Installation)
MRCOOL Olympus 4th Generation 2-Zone Ductless Mini Split AC & Heat Pump 18000 BTU (12K+12K), Ceiling Cassette Units, 230V
A space-saving ceiling cassette solution with a clean, flush look, quiet operation, and multi-zone comfort for up to six rooms.
Overview
18000 BTU
2 Zones
25.1 SEER2
Operates to -13°F
R-454B
SmartHVAC App
Alexa & Google
Ceiling Cassette
Quiet Operation
Designed to fit seamlessly into the ceiling for a flush look, Olympus ceiling cassettes help free up wall space while delivering efficient, even comfort. Multi-zone systems run in one mode at a time (the system heats or cools as a whole).
System Combination
MULTI3-18HP230C-O + 2X CASSETTE12HP-230C-P-O
MULTI3-18HP230C-O + 2X CASSETTE12HP-230C-P-O
Outdoor Model
MULTI3-18HP230C-O
MULTI3-18HP230C-O
Min Circuit Ampacity
16.0
16.0
Max Fuse / Breaker
20
20
Why Homeowners Love It
- Clean, modern aesthetic: Ceiling-mounted design delivers a discreet, flush appearance that blends into the room.
- Save wall space: Ideal when wall space is limited or you prefer an uncluttered layout.
- Quiet comfort: Designed for low-noise operation—great for bedrooms, offices, and nurseries.
- Multi-zone control: Flexible zone-by-zone comfort for up to six areas with one outdoor unit.
- Smart control: Manage schedules and setpoints using SmartHVAC app plus Alexa/Google voice control.
Important: This system is not DIY—professional installation is required.
What’s Included
- (1) Outdoor condenser: MULTI3-18HP230C-O
- Indoor ceiling cassettes:
- 12,000 BTU (x2) — Model: CASSETTE12HP-230C-P-O
- Zone remotes/controllers (model-specific)
- Refrigerant line sets & interconnect/communication wiring (must be selected in the options to be included; choose the appropriate length for each indoor unit based on your layout)
- Mounting/ceiling hardware (model-specific)
- Installation documentation (see Documents & Downloads)
Mrcool DIY Multi-Zones
Key Features
- Space-saving ceiling design: Flush look that maximizes usable wall space.
- Advanced inverter efficiency: High performance with strong SEER2 ratings (varies by model pairing).
- Low-ambient cooling capability: Suitable for specialty cooling needs in colder weather (application dependent).
- Refrigerant leak detection: Built-in monitoring with fault indication to help protect the system.
- Gold Fin® condenser: Added corrosion resistance for long-term durability.
- SmartHVAC control: App scheduling + remote access, plus Alexa/Google voice integration.
R-454B is an A2L refrigerant. Installation/service must follow the manufacturer manual and applicable codes.
Comfort Modes
- Auto: Automatically selects heating or cooling to maintain setpoint.
- Cool / Heat: Dedicated modes for seasonal comfort.
- Dry: Dehumidifies while maintaining comfort.
- Sleep: Energy-saving overnight profile.
- Timer: Scheduled on/off for efficiency.
Multi-zone systems operate in one mode at a time—you can’t heat one room while cooling another.
Warranty
Standard coverage commonly includes a 7-year compressor warranty and a 5-year parts warranty (registration requirements apply).
Extended limited lifetime replacement coverage may require MRCOOL® Care Kit enrollment and additional conditions/fees. Some extended program terms may exclude certain indoor types—confirm program details for ceiling cassette configurations.
Indoor Specs
Indoor Unit Specifications — CASSETTE12HP-230C-P-O
| brand name | MRCOOL |
|---|---|
| series | Olympus Cassette |
| model | CASSETTE12HP-230C-P-O |
| unit type | Mini-Split |
| short description | Olympus 12,000 BTU 1 Ton Ductless Mini-Split Ceiling Cassette with Panel - 230V/60Hz |
| long description | The MRCOOL® OLYMPUS 12K CASSETTE delivers reliable heating and cooling for areas up to 550 square feet, making it an excellent option for bedrooms, home offices, or other smaller spaces. Designed to be installed flush within the ceiling, it blends seamlessly into your room, offering a sleek, modern look that enhances any décor. This versatile system is perfect for both residential and commercial spaces, maximizing room usage while providing an efficient and stylish climate control solution. Operating at a quiet 46 dB, the indoor fan ensures that your space remains calm and undisturbed while still delivering consistent performance. Its low noise level allows for optimal heating or cooling without distracting sounds, making it ideal for environments that require peace, such as bedrooms, home offices, or nurseries. The quiet operation creates a comfortable atmosphere that enhances relaxation and productivity. The system uses R-454B refrigerant, a sustainable choice that balances high performance with environmental responsibility. With its low global warming potential, R-454B minimizes the environmental impact of your unit while offering exceptional efficiency. This makes it a great option for homeowners looking to reduce their carbon footprint while still enjoying reliable, top-quality performance. The MRCOOL® OLYMPUS 12K CASSETTE is backed by a limited lifetime warranty, 7 years of compressor coverage, and a 5-year parts warranty, ensuring lasting reliability and cutting-edge technology. This system is the perfect fit for those who prioritize energy efficiency, modern style, and optimal comfort. |
| works with | O-ES-12-HP-C-230C-O1 MULTI3-18HP230C-O MULTI4-27HP230C-O MULTI5-36HP230C-O MULTI6-48HP230C-O |
| tonnage | 1.0 |
| voltage (v) | 208/230 |
| phase | 1 |
| cycle (hz) | 60 |
| max fuse breaker (a) | 15 |
| min circuit ampacity (a) | 3.0 |
| mount type | Ceiling |
| color | White |
| max coverage area | Up to 550 |
| refrigerant type | R-454B |
| decibel rating (dba) | 46/43.5/40.5/27.5/26 |
| decibel rating low (dba) | 26.0 |
| decibel rating high (dba) | 46.0 |
| air flow direction | Downflow |
| number of speeds | 5 (Variable) |
| oscillation | Yes |
| lineset fitting type | Flare |
| liquid line size | 1/4 |
| suction line size | 3/8 |
| blower motor speeds | 417.9/364.9/306.1/194.2/147.2 |
| blower motor rpm | 700/600/400 |
| filter type | Reusable |
| auxiliary heater included | No |
| auxiliary heater available | No |
| fan only option | Yes |
| sleep mode | Yes |
| auto cool | Yes |
| wifi compatibility | No |
| app compatibility | No |
| works with ios | No |
| works with android | No |
| remote control included | Yes |
| ul listed | Yes |
| csa listed | Yes |
| etl listed | Yes |
| base warranty | 5-Year Parts |
| base parts warranty | 5-Year |
| base remote warranty | 5 Year |
| registered labor warranty | None |
| base labor warranty | None |
| has batteries | Yes |
| contains electronics | Yes |
| contains chemicals | Yes |
| contains compressed gas | Yes |
| proposition 65 warning | Yes |
| restricted states | GU, PR, VI |
| net depth (in) | 24.44 |
| net height (in) | 9.65 |
| net width (in) | 22.44 |
| net weight | 35.27 |
| gross weight (lbs) | 41.89 |
Manuals
- https://doxrepo.mrcool.com/mc-oly-mz-4g-cass-im-um-en-01.pdf
- https://doxrepo.mrcool.com/mc-oly-mz-4g-cass-sm-en-01.pdf
Submittals
Documents
Warranty
Outdoor Specs
Outdoor Unit Specifications — MULTI3-18HP230C-O
| brand name | MRCOOL |
|---|---|
| series | Olympus 4th Gen Multi-Zone Condensers |
| model | MULTI3-18HP230C-O |
| unit type | Mini-Split |
| short description | Olympus 18,000 BTU Mini-Split Condenser - 230V/60Hz |
| long description | The MRCOOL® Olympus MULTI3-18HP230C-O is a high-performance 18,000 BTU multi-zone heat pump condenser designed to power up to three indoor units simultaneously. Perfect for homeowners looking to efficiently manage temperatures in multiple spaces, this ductless system offers individualized climate control for each connected zone, making it a flexible solution for modern living environments. Built with advanced inverter technology, the unit delivers impressive efficiency, with SEER2 ratings up to 25.1 and HSPF2-4 up to 10. It performs reliably in diverse conditions, operating in outdoor temperatures as low as 5°F, ensuring comfort in both summer and winter months. This model is compatible with various MRCOOL indoor units, including wall-mounted, ceiling cassette, and concealed duct options, giving users the freedom to tailor the system to their home’s layout and aesthetics. Smart features elevate user convenience, with control options that include the MRCOOL SmartHVAC app, traditional remotes, or even voice commands via Amazon Alexa and Google Assistant. Additional functions such as sleep mode, auto restart, and refrigerant leak detection contribute to enhanced safety and comfort. Backed by a 7-year warranty on the compressor and 5 years on parts (with professional installation), the MRCOOL®Olympus MULTI3-18HP230C-O is a reliable and energy-efficient choice for those seeking customized, zone-specific heating and cooling. |
| works with | O-09-HP-WMAH-230C-O DUCT-09HP-230B-O CASSETTE09HP-230C-O O-12-HP-WMAH-230C-O DUCT-09HP-230B-O CASSETTE12HP-230C-O |
| feature list | Installation by a licensed professional required where applicable 7-Year Compresser, 5-Year Parts warranty when registered and installed by a licensed professional R-454B environmentally friendly refrigerant Energy Star Certified |
| seer2 | Up to 25.1 |
| eer2 | Up to 14 |
| hspf2-4 | 9.8 |
| hspf2-5 | 7.8 |
| tonnage | 1.5 |
| cooling capacity (btu) | 18000.0 |
| heating capacity (btu) | 19000.0 |
| voltage (v) | 208/230 |
| phase | 1 |
| cycle (hz) | 60 |
| max fuse breaker (a) | 20 |
| min circuit ampacity (a) | 16.0 |
| color | White |
| max coverage area | Up to 750 |
| zone capacity | 3.0 |
| refrigerant type | R-454B |
| refrigerant volume (oz) | 61.73 |
| decibel rating (dba) | 59.5 |
| inverter | DC |
| max lineset length (ft) | 196.8 total |
| lineset fitting type | Flare |
| compressor motor type | Twin-Rotary |
| condenser fan motor rpm | 750/600/500 |
| metering device | EXV + Capillary |
| ul listed | Yes |
| csa listed | Yes |
| etl listed | Yes |
| energy star certified | Yes |
| ahri certified | Yes |
| base warranty | 5-Year Parts/7-Year Compressor |
| base parts warranty | 5-Year |
| base compressor warranty | 7-Year |
| base remote warranty | 5 Year |
| registered labor warranty | None |
| base labor warranty | None |
| has batteries | Yes |
| contains electronics | Yes |
| contains chemicals | Yes |
| contains compressed gas | Yes |
| proposition 65 warning | Yes |
| restricted states | GU, PR, VI |
| net depth (in) | 13.46 |
| net height (in) | 26.5 |
| net width (in) | 35.04 |
| net weight | 100.53 |
| gross depth (in) | 17.24 |
| gross height (in) | 29.53 |
| gross width (in) | 40.55 |
| gross weight (lbs) | 109.35 |
Manuals
- https://doxrepo.mrcool.com/mc-oly-mz-4g-im-um-en-01.pdf
- https://doxrepo.mrcool.com/mc-oly-mz-4g-sm-en-01.pdf
Documents
Warranty
Helpful Notes
Professional installation required
Installation must be completed by a qualified HVAC professional. Improper installation can cause water leakage, electrical shock, or fire.
Mode limitation (multi-zone)
The system heats or cools as a whole. You can’t heat one room while cooling another at the same time.
Line sets & wiring (options)
Line sets and communication wiring may be bundled depending on your selected options. If no installation kit is selected, they may not be included. Select the appropriate length for each indoor unit based on your layout.
Electrical & breaker sizing
Use MCA (16.0) and Max Fuse/Breaker (20) as starting points, then size per the installation manual and local code.
Line sizing
Indoor line sizes: 1/4 / 3/8. Confirm final line sizes, allowable lengths, and any additional charge requirements for your exact pairing before selecting line sets.
