MRCOOL Olympus Multi-Zone 4th Gen — Mini Split Heat Pump System (Professional Installation)
MRCOOL Olympus 4th Generation 2-Zone Ductless Mini Split AC & Heat Pump 27000 BTU (9K+18K), Wall Mount Units, 230V
Premium performance for up to six zones with advanced inverter efficiency, SmartHVAC control, and durable Gold Fin® protection.
Overview
27000 BTU
2 Zones
25 SEER2
Operates to -13°F
R-454B
SmartHVAC App
Alexa & Google
Wall Mount Air Handlers
The Olympus Multi-Zone 4th Gen is built for whole-home flexibility—one outdoor condenser can support multiple indoor zones for independent room comfort. Note: multi-zone systems run in one mode at a time (the system heats or cools as a whole).
System Combination
MULTI4-27HP230C-O + O-09-HP-WMAH-230C-O + O-18-HP-WMAH-230C-O
MULTI4-27HP230C-O + O-09-HP-WMAH-230C-O + O-18-HP-WMAH-230C-O
Outdoor Model
MULTI4-27HP230C-O
MULTI4-27HP230C-O
Min Circuit Ampacity
23.0
23.0
Max Fuse / Breaker
25
25
Why Homeowners Love It
- Your comfort, multiplied: Multi-zone technology gives room-by-room temperature control in up to six zones.
- Premium efficiency: Advanced inverter performance helps reduce monthly heating and cooling costs.
- All-season reliability: Dependable low-ambient operation and stable comfort in changing outdoor conditions.
- Smart control: Set schedules, adjust setpoints, and manage zones from the SmartHVAC app (plus Alexa/Google voice).
- Built to last: Gold Fin® condenser protection improves corrosion resistance—ideal for harsh or coastal regions.
Important: This system is not marketed as DIY—professional installation is required.
What’s Included
- (1) Outdoor condenser: MULTI4-27HP230C-O
- Indoor wall mounts:
- 9,000 BTU (x1) — Model: O-09-HP-WMAH-230C-O
- 18,000 BTU (x1) — Model: O-18-HP-WMAH-230C-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 hardware for indoor units
- Installation documentation (see Documents & Downloads)
Mrcool DIY Multi-Zones
Key Features
- Advanced inverter technology: High efficiency and stable comfort with variable-speed performance.
- Low-ambient cooling: Designed for applications that may require cooling in colder weather (e.g., server rooms / greenhouses).
- 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.
- Comfort features: Sleep mode, auto restart, and diagnostic codes (model-specific).
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 enrollment in the MRCOOL® Care Kit program and additional conditions/fees.
Indoor Specs
Indoor Unit Specifications — O-09-HP-WMAH-230C-O
| brand name | MRCOOL |
|---|---|
| series | Olympus 4th Gen Air Handlers |
| model | O-09-HP-WMAH-230C-O |
| unit type | Mini-Split |
| short description | Olympus 9,000 BTU 3/4 Ton Ductless Mini-Split Wall Mounted Air Handler - 230V/60Hz |
| long description | Enjoy reliable heating and cooling with the MRCOOL® OLYMPUS ESTAR® 9k Series air handler, designed to deliver year-round comfort for spaces up to 400 square feet—ideal for single rooms, home offices, garages, and more. Its compact size allows for quick and easy installation, making setup a breeze for your installer. Equipped with the MRCOOL® Smart HVAC app, this unit offers convenient Wi-Fi connectivity, letting you control it from your smartphone or tablet, no matter where you are. Prefer a more traditional approach? Use the included remote control for simple access to your preferred settings. Built with efficiency in mind, the unit boasts impressive performance ratings: SEER2 of 25.8, EER2 of 14.9, and HSPF2-4 of 12.5—helping you cut down on energy costs. With multiple indoor fan speeds and whisper-quiet operation at just 47 dB, you’ll barely notice it’s there while enjoying consistent comfort. Now using eco-friendly R-454B refrigerant, this system is better for the environment without compromising on power or performance. You’ll also enjoy versatile control options, including voice command compatibility with Amazon Alexa and Google Assistant. Backed by an industry-leading warranty—including a limited lifetime warranty, 7-year compressor coverage, and a 5-year parts warranty—the MRCOOL® OLYMPUS ESTAR® 9k Series offers advanced technology, dependable performance, and personalized climate control for years to come. |
| works with | O-ES-09-HP-C-230C-O1 MULTI3-18HP230C-O MULTI4-27HP230C-O MULTI5-36HP230C-O MULTI6-48HP230C-O |
| tonnage | 0.75 |
| voltage (v) | 208/230 |
| phase | 1 |
| cycle (hz) | 60 |
| max fuse breaker (a) | 15 |
| min circuit ampacity (a) | 3.0 |
| mount type | Wall |
| color | White |
| max coverage area | Up to 400 |
| refrigerant type | R-454B |
| decibel rating (dba) | 38/38/33/20.5/19.5 |
| decibel rating low (dba) | 19.5 |
| decibel rating high (dba) | 38.0 |
| number of speeds | 5 (Variable) |
| oscillation | Yes |
| lineset fitting type | Flare |
| liquid line size | 1/4 |
| suction line size | 3/8 |
| blower motor speeds | 441.4/323.7/229.6/176.6/147.2 |
| blower motor rpm | 1100/850/700 |
| filter type | Reusable |
| auxiliary heater included | No |
| auxiliary heater available | No |
| fan only option | Yes |
| sleep mode | Yes |
| auto cool | Yes |
| wifi compatibility | Yes |
| app compatibility | Yes |
| works with ios | Yes |
| works with android | Yes |
| 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) | 9.09 |
| net height (in) | 11.81 |
| net width (in) | 33.74 |
| net weight | 23.37 |
| gross depth (in) | 12.2 |
| gross height (in) | 14.57 |
| gross width (in) | 36.22 |
| gross weight (lbs) | 29.98 |
Indoor Unit Specifications — O-18-HP-WMAH-230C-O
| brand name | MRCOOL |
|---|---|
| series | Olympus 4th Gen Air Handlers |
| model | O-18-HP-WMAH-230C-O |
| unit type | Mini-Split |
| short description | Olympus 18,000 BTU 1.5 Ton Ductless Mini-Split Wall Mounted Air Handler - 230V/60Hz |
| long description | Enjoy peace of mind and reliable comfort with the MRCOOL® OLYMPUS ESTAR® 18k Series air handler, designed to efficiently heat and cool areas up to 800 square feet—making it an ideal choice for large rooms, offices, garages, and more. Thanks to its compact design, installation is fast and straightforward. Control your comfort from anywhere with the MRCOOL® Smart HVAC app, which allows Wi-Fi connectivity for remote access via your smartphone or tablet. For added convenience, the unit also includes a wireless remote control, giving you flexible options to manage your indoor climate with ease. Engineered for energy efficiency, this system features a SEER2 rating of 23.5, EER2 of 12.7, and HSPF2-4 of 10.8, helping you lower your utility costs while staying comfortable year-round. With multiple fan speed settings and whisper-quiet operation at just 49 dB, it delivers powerful performance with minimal noise. Now using R-454B refrigerant, a more eco-friendly choice, this unit supports environmentally conscious living without sacrificing performance. Enjoy seamless control options, including the smartHVAC app, wireless remote, and voice control compatibility with Amazon Alexa and Google Assistant, giving you personalized comfort at your fingertips. Backed by an industry-leading warranty—including a limited lifetime warranty, 7-year compressor warranty, and 5-year parts warranty—the MRCOOL® OLYMPUS ESTAR® 18k Series air handler offers dependable performance, smart technology, and lasting comfort throughout the seasons. |
| works with | O-ES-18-HP-C-230C-O1 MULTI4-27HP230C-O MULTI5-36HP230C-O MULTI6-48HP230C-O |
| tonnage | 1.5 |
| voltage (v) | 208/230 |
| phase | 1 |
| cycle (hz) | 60 |
| max fuse breaker (a) | 15 |
| min circuit ampacity (a) | 3.0 |
| mount type | Wall |
| color | White |
| max coverage area | Up to 800 |
| refrigerant type | R-454B |
| decibel rating (dba) | 49.5/45/38/31.5/19.5 |
| decibel rating low (dba) | 19.5 |
| decibel rating high (dba) | 49.5 |
| number of speeds | 5 (Variable) |
| oscillation | Yes |
| lineset fitting type | Flare |
| liquid line size | 1/4 |
| suction line size | 1/2 |
| blower motor speeds | 635.7/500.3/359/294.3/294.3 |
| blower motor rpm | 1190/994/896 |
| filter type | Reusable |
| auxiliary heater included | No |
| auxiliary heater available | No |
| fan only option | Yes |
| sleep mode | Yes |
| auto cool | Yes |
| wifi compatibility | Yes |
| app compatibility | Yes |
| works with ios | Yes |
| works with android | Yes |
| 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) | 9.69 |
| net height (in) | 12.64 |
| net width (in) | 40.31 |
| net weight | 27.34 |
| gross depth (in) | 12.8 |
| gross height (in) | 15.75 |
| gross width (in) | 43.11 |
| gross weight (lbs) | 36.6 |
Manuals
- https://doxrepo.mrcool.com/mc-oly-sz-4g-im-um-en-01.pdf
- https://doxrepo.mrcool.com/mc-oly-sz-4g-sm-en-01.pdf
Submittals
Documents
Warranty
Outdoor Specs
Outdoor Unit Specifications — MULTI4-27HP230C-O
| brand name | MRCOOL |
|---|---|
| series | Olympus 4th Gen Multi-Zone Condensers |
| model | MULTI4-27HP230C-O |
| unit type | Mini-Split |
| short description | Olympus 27,000 BTU Mini-Split Condenser - 230V/60Hz |
| long description | The MRCOOL® Olympus MULTI4-27HP230C-O is a powerful 27,000 BTU multi-zone heat pump condenser capable of supporting up to four indoor units at once. Ideal for homeowners aiming to maintain precise temperature control in multiple areas, this ductless system allows for customized climate settings in each zone, offering a versatile and energy-smart solution for today’s homes. Engineered with advanced inverter technology, it boasts impressive energy efficiency—reaching SEER2 ratings up to 25 and HSPF2-4 up to 9.5. Designed to perform in a wide range of outdoor temperatures, this unit remains reliable even in cold weather down to 5°F, delivering year-round comfort. It’s also compatible with a variety of MRCOOL indoor unit types, including wall-mounted, ceiling cassette, and concealed duct options, making it easy to tailor the system to your home’s design and needs. Convenience is built in, with smart control options like the MRCOOL SmartHVAC app, handheld remotes, or voice control via Amazon Alexa and Google Assistant. Additional features such as sleep mode, auto restart, and refrigerant leak detection provide added safety, ease of use, and peace of mind. Covered by a 7-year compressor warranty and a 5-year parts warranty (when professionally installed), the MRCOOL® Olympus MULTI4-27HP230C-O is a dependable, high-efficiency choice for those seeking flexible, 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-12HP-230B-O CASSETTE12HP-230C-O O-18-HP-WMAH-230C-O DUCT-18-HP-230B-O CASSETTE18HP-230C-O O-24-HP-WMAH-230C-O DUCT-24HP-230B-O CASSETTE24HP-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 friendly refrigerant Energy Star Certified |
| seer2 | Up to 25 |
| eer2 | Up to 13 |
| hspf2-4 | 9.5 |
| hspf2-5 | 7.0 |
| tonnage | 2.25 |
| cooling capacity (btu) | 27000.0 |
| heating capacity (btu) | 27000.0 |
| voltage (v) | 208/230 |
| phase | 1 |
| cycle (hz) | 60 |
| max fuse breaker (a) | 25 |
| min circuit ampacity (a) | 23.0 |
| color | White |
| max coverage area | Up to 1125 |
| zone capacity | 4.0 |
| refrigerant type | R-454B |
| refrigerant volume (oz) | 84.66 |
| decibel rating (dba) | 61 |
| inverter | DC |
| max lineset length (ft) | 262.4 total |
| lineset fitting type | Flare |
| compressor motor type | Rotary |
| condenser fan motor rpm | 800/700/650 |
| metering device | EXV |
| 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) | 16.14 |
| net height (in) | 31.89 |
| net width (in) | 37.24 |
| net weight | 138.89 |
| gross depth (in) | 19.68 |
| gross height (in) | 34.84 |
| gross width (in) | 42.91 |
| gross weight (lbs) | 149.69 |
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.
Mixing indoor unit types
Many Olympus multi-zone configurations allow mixing compatible indoor styles (wall mounts, ceiling cassettes, and concealed duct models). Confirm compatibility for your condenser model before ordering.
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 (23.0) and Max Fuse/Breaker (25) as starting points, then size per the installation manual and local code.
Line sizing
Indoor line sizes: 1/4 / 3/8 | 1/4 / 1/2. Confirm final line sizes, allowable lengths, and any additional charge requirements for your exact pairing before selecting line sets.
