Mini Split 18,000 BTU Daikin Oterra 21 SEER2 WiFi Cool Only System, RKF18BVJU9, FTKF18BVJU9
Holding 21.00 SEER2 at a full ton and a half is what makes the RKF18BVJU9 stand out — most ductless lines shed efficiency as capacity climbs, and the Oterra does not. Matched with the FTKF18BVJU9 wall-mounted air handler, this cool-only system delivers 18,000 BTU/h with no heat pump function and no supplemental heat, running on R-32 refrigerant with a variable-speed inverter that turns down to 6,900 BTU/h and boosts to 22,000 BTU/h. It also crosses an important threshold: the 18K jumps to a 99-foot maximum line length and 66 feet of vertical rise, which is what makes second-story and long-run installations practical. A backlit wireless remote is included and the system is Wi-Fi capable through the DKN Cloud interface.
Is an 18,000 BTU Cool-Only System the Right Size?
A ton and a half is the first Oterra capacity that comfortably handles more than one room's worth of load. That makes it the usual pick for open living-and-kitchen areas, great rooms with cathedral ceilings, large finished garages, and commercial bays where a single wall-mounted head has to cover an entire space. Rated cooling is 18,000 BTU/h with sensible capacity of 14,590 BTU/h, and the operating envelope widens too — standard cooling runs all the way to 122°F ambient rather than 118°F.
Sizing an open area is less about the total footprint and more about how air actually moves through it. A single head cannot push conditioned air around a corner or down a hallway, so consider throw distance, ceiling fans, and whether doorways stay open. Insulation quality, glass area, skylights, cooking equipment, and occupant count all push the number up; a tight, shaded, single-occupant space pulls it down. If one head cannot reach every corner, a multi-zone layout is often the better answer than simply buying more tonnage.
Ideal for: Great rooms, open living and dining combinations, large finished garages and shops, restaurant dining rooms, gyms, classrooms, and commercial retail bays.
Need more capacity? Step up to the 24,000 BTU Daikin Oterra 21 SEER2 Cool Only System RKF24BVJU9, FTKF24BVJU9 for larger open areas and higher sensible loads. Covering several separate rooms instead? Compare the multi zone mini split systems.
Recommended applications are general guidelines only. Actual system requirements depend on insulation, window area, ambient conditions, occupancy, internal heat gain, and installation details. Request free sizing assistance, contact Budget Heating, or call 813-885-7999.
What's Included
| Outdoor Condensing Unit | RKF18BVJU9 — 1.5 Ton Oterra Cool Only Inverter Condenser |
|---|---|
| Indoor Air Handler | FTKF18BVJU9 Wall-Mounted Ductless Air Handler |
| Operating Mode | Cool Only — No Heat Pump, No Electric Heat |
| Rated Cooling Capacity | 18,000 BTU/h (modulates 6,900 – 22,000 BTU/h) |
| Efficiency | 21.00 SEER2 / 12.00 EER2 — 14,590 BTU/h Sensible |
| Refrigerant | R-32, 2.45 lb Factory Charge |
| Line Set Sizes | 1/4" Liquid × 1/2" Suction — 99 ft Max Total, 66 ft Max Vertical |
| Electrical | 208-230V, Single Phase, 60 Hz — 21.4 A MCA, 25 A MOCP |
| Controls | Backlit Wireless Remote Included — Wi-Fi Capable via DKN Cloud Adaptor (Sold Separately) |
| AHRI Certificate | 217005893 |
Two things change at this capacity that installers should plan for. The suction line grows to 1/2", so this system needs a 1/4" and 1/2" insulated copper line set — or a 25 ft copper and 14/4 wire installation combo that bundles the communication wire with it. The condenser also steps up to a 25 A maximum overcurrent device at 21.4 A MCA, which means a dedicated 25 A circuit rather than the 15 A feed the smaller Oterra models use.
Outdoor Condenser & Air Handler Features
RKF18BVJU9 Outdoor Condensing Unit
- Cool-only inverter platform holding a full 21.00 SEER2 at 1.5 tons
- Standard cooling operation extended to 122°F ambient
- 99 ft maximum total line length and 66 ft maximum vertical rise
- 2,327 CFM condenser airflow moves heat efficiently on hot days
- 54 dBA outdoor sound pressure on high speed
- R-32 factory charge of 2.45 lb, pre-charged for 49 ft of line set
- Low-ambient cooling to -4°F with the air direction adjustment grille
- 29-1/2" x 34-1/4" x 12-5/8" cabinet, 113 lb
- Anti-corrosion heat exchanger treatment standard
- 21.4 A MCA on a 25 A maximum overcurrent device
FTKF18BVJU9 Wall-Mounted Air Handler
- 39-3/8" wide cabinet with the throw to cover an open great room
- 565 / 463 / 378 / 335 CFM across four fan speeds
- 33 dBA on Super Low despite the larger blower
- Titanium apatite photocatalytic air-purifying filter included
- Wide-angle louvers with dual flap 3-D airflow distribution
- Intelligent Eye occupancy sensing trims output in empty rooms
- Night Set mode drifts the setpoint for overnight savings
- Backlit wireless remote controller in the carton
- Wi-Fi ready for the Daikin AZAI6WSPDKC wireless interface with wall thermostat support
- Self-diagnostics with fault display for faster service calls
Specifications & Manuals
Product documentation includes the factory submittal with full performance and electrical data, installation instructions, and warranty information to assist with equipment selection, installation, and service.
Frequently Asked Questions
How far can the line set run on the RKF18BVJU9?
Up to 99 feet total with a maximum 66 feet of vertical separation, pre-charged for the first 49 feet. That is a significant increase over the 66 ft / 49 ft limits of the 9K and 12K Oterra models, and it is what makes a roof-mounted or grade-level condenser serving an upstairs room feasible.
Why does the 18K have a lower EER2 than the 12K if both are 21 SEER2?
SEER2 is a seasonal average across a range of conditions, while EER2 is measured at a single hot design point. The 18K rates 12.00 EER2 versus 12.50 for the smaller models, meaning it gives up a little peak-day efficiency while matching the seasonal number.
Can one 18,000 BTU head cool two separate bedrooms?
Not effectively. A wall-mounted head conditions the space it can throw air into, so a wall or hallway between rooms will leave the far room warm regardless of capacity. Two smaller heads on a multi zone condenser is the correct approach for separate rooms.
Does the Intelligent Eye sensor turn the system off when nobody is home?
It does not shut down; it shifts the setpoint to reduce output when it detects no motion in the space, then returns to the programmed temperature once occupancy resumes. It is a comfort and consumption feature, not an occupancy lockout.
What outdoor ambient temperature can the 18K cool at?
Standard cooling operation runs from 50°F to 122°F, which is the widest high-side range in the Oterra cool-only lineup. Low-ambient operation extends to -4°F with the air direction adjustment grille fitted.
Is the RKF18BVJU9 heavy enough to need two people to set?
At 113 pounds it is roughly a two-person lift. Plan on a helper or lifting straps, and confirm any wall bracket is rated for the load before mounting rather than setting it on a ground pad.
Daikin RKF18BVJU9, FTKF18BVJU9 Submittal
