LG KNMKB091A Low Static Ducted Indoor Unit with 9000 BTU Cooling Capacity, 10400 BTU Heating Capacity and Washable Filter in Silver

LG's devotion to providing efficient ductless solutions can be seen across the Multi F line of indoor units. The KNMKB091A is a mini split indoor unit designed for installation in short-run ducting with low static pressures. Concealed duct indoor units mean that you can add mini split zones with no visible indoor units. A small air register is the only clue that a mini split is providing effective heating and cooling to your space.

• AHRI Certified 
• Sleep Mode

Enhanced Connectivity

LG's new R-32 mini split units require a 5-conductor cable (Not Included) instead of the standard 4-conductor, improving communication reliability and enabling a new leak detection feature.

Quiet Design

The unit can operate at volumes as low as 23 dB thanks to its advanced fan motor. The brushless direct current motor reduces electrical and mechanical sound while providing powerful air movement.

Automated Operation

Auto operation mode continually compares your zone's current and desired temperatures and uses that data to intelligently adjust the unit's fan speed and refrigerant flow to provide optimal comfort.

Condensate Protection

Condensate overflow can damage your indoor unit and your home. An internal condensate pump with 27.5" of lift protects the unit  through reliable, effective condensate removal.

Dehumidify

LG's indoor units include a dehumidifying operation mode. In this mode, the unit's internal sensors monitor temperature and modify the set point and fan speed to remove moisture from the air.

Improved Air Quality

The unit  features an anti-fungal filter to keep your air clean. This filter captures contaminants like dust and bacteria, and it is washable to ensure long term air quality.

Hot-Start

When the Hot-Start function is enabled, the unit's fan will not engage until the outdoor condenser has had the opportunity to warm the indoor coil. This prevents the unit from blowing cold air during heating operations.

Matching Products

• Matching 18000 BTU Multi-Zone Outdoor Unit KUMXB181A
• Matching 24000 BTU Multi-Zone Outdoor Unit KUMXB241A
• Matching 30000 BTU Multi-Zone Outdoor Unit KUMXB301A
• Matching 36000 BTU Multi-Zone Outdoor Unit KUMXB361A
• Matching 48000 BTU Multi-Zone Outdoor Unit KUMXB481A
• Matching 54000 BTU Multi-Zone Outdoor Unit KUMXB541A
• Matching 60000 BTU Multi-Zone Outdoor Unit KUMXB601A
• Matching 18000 BTU LGRED Multi-Zone Outdoor Unit KUMXA181A
• Matching 24000 BTU LGRED Multi-Zone Outdoor Unit KUMXA241A
• Matching 30000 BTU LGRED Multi-Zone Outdoor Unit KUMXA301A
• Matching 36000 BTU LGRED Multi-Zone Outdoor Unit KUMXA361A
• Matching 42000 BTU LGRED Multi-Zone Outdoor Unit KUMXA421A

• Matching 48000 BTU LGRED Multi-Zone Outdoor Unit KUMXA481A

Why Buy LG KNMKB091A Low Static Ducted Indoor Unit

• Space-Saving Design: Its slim profile allows for installation in tight ceiling spaces, delivering both heating and cooling without exposing bulky indoor units.
• Short Duct Runs: Designed specifically for low static pressure applications, this unit excels in short duct configurations where extended runs aren’t feasible.
• Discreet Aesthetics: With only a small air register visible, the system maintains a clean, unobtrusive appearance in any room.
• Quiet Operation: A brushless DC motor enables whisper-quiet performance
• Flexible Installation: Rear or bottom air intake options allow for adaptable installation based on your space and layout needs.
• Energy Efficiency: Features like auto operation and Sleep Mode help optimize comfort while reducing overall energy consumption.

• Concealed Duct Advantage: Unlike wall-mounted systems, this concealed unit offers central system comfort without compromising interior aesthetics.

Frequently Asked Questions

Q: What is the LG KNMKB091A?

A: The LG KNMKB091A is a 9,000 BTU concealed duct indoor unit designed for use in a multi-zone ductless mini-split heat pump system.

• It’s a low-static pressure unit suitable for installations where only minimal ducting is needed.
• As a concealed duct unit, it is installed inside a ceiling or wall—only the air register is visible in the room.
• It must be connected to a compatible LG multi-zone outdoor condenser to operate.

Q: What accessories are required for installation?

A: Several components are needed to complete the system, as the KNMKB091A is not a standalone unit.

• Outdoor condenser unit: Must be an LG-compatible multi-zone model.
• Remote control & cable: Typically a wired controller like the PREMTC00U, along with an extension cable.
• Line set: Double-insulated refrigerant tubing connects indoor and outdoor units.
• Connecting wire: A 5-conductor communication cable is required for R-32 refrigerant systems.

Q: Why is my unit running but not cooling properly?

A: This is often caused by airflow restrictions, most commonly from a dirty air filter.

• Check the air filter for dust or blockage.
• Clean or replace the filter as needed.
• Ensure that vents and ductwork are unobstructed.

Q: Why won’t the unit start at all?

A: Power issues or seasonal settings may be preventing the unit from starting.

• Check if the circuit breaker has tripped and reset it if necessary.
• If using the unit in winter, ensure proper winterization procedures were followed.
• Confirm that the outdoor condenser is receiving power and communication from the indoor unit.

Q: What does the error code CH05 mean?

A: CH05 typically indicates a communication error between the indoor and outdoor units.

• Inspect the wiring between the indoor and outdoor units.
• Check that the circuit breaker for the outdoor unit is not tripped.
• A professional technician may be required for further diagnostics.

Q: What does the error code CH61 mean?

A: CH61 signals that the outdoor unit’s heat exchanger may be overheating.

• Ensure the area around the outdoor condenser is well-ventilated.
• Remove any debris or obstructions near the unit.
• If the issue persists, consult an HVAC professional.

Q: Why is my unit making unusual noises?

A: Some sounds are part of normal operation, but unfamiliar noises should be investigated.

• Listen closely to identify the type of noise (e.g., clicking, buzzing, gurgling).
• Refer to the LG support website, which includes audio samples of normal and abnormal sounds.

• Contact LG support or an HVAC technician if you're unsure.

Pros and Cons for LG KNMKB091A Low Static Ducted Indoor Unit

Pros

• Discreet installation: Because the unit is concealed within a wall or ceiling, it provides heating and cooling with only small, visible air registers, preserving the look of your interior space.
• Quiet operation: The KNMKB091A operates at sound levels as low as 23 dB, comparable to a whisper. Its brushless direct current (BLDC) fan motor helps reduce both electrical and mechanical noise.
• High efficiency: As part of an inverter-driven mini-split system, it precisely regulates the refrigerant flow and fan speed, leading to consistent temperatures and lower energy consumption compared to traditional systems.
• Space-saving design: With a slim profile, the unit can be installed in tight ceiling spaces, making it an ideal solution for projects with limited installation space.
• Convenience features: The unit includes several automated functions, such as auto operation mode to maintain temperature, a sleep mode for energy savings, and a built-in condensate pump with 27.5 inches of lift to prevent overflow.
• Improved air quality: It comes with a washable anti-fungal filter that captures dust and bacteria, contributing to cleaner air.
• Reliable heating: The "Hot-Start" feature prevents the unit from blowing cold air during heating cycles by waiting for the coil to warm up before the fan engages.

Cons

• Requires professional installation: Like all mini-split systems, the low static duct unit needs professional installation, which involves specialized training and tools for handling the refrigerant and electrical connections. It is not a DIY-friendly project.
• Limited static pressure: As a low-static model, it is optimized for short duct runs. Using it with longer, more complex ductwork can significantly reduce its performance and efficiency, requiring a mid-static or high-static unit instead.
• Higher installation costs: The installation cost is generally higher than that of a standard wall-mounted mini-split because of the labor involved in running ductwork and concealing the unit.
• Brand support issues: Some users have reported negative experiences with LG's technical support and warranty claims for their mini-split products.
• Dependency on other components: The indoor unit requires a compatible outdoor condenser, a specific 5-conductor communication cable, and a separate remote controller for operation. These items are sold separately and must be properly matched.

Conclusion

The LG KNMKB091A is an excellent choice for homeowners or small commercial applications that prioritize aesthetics and quiet operation. Its concealed design and low sound levels offer a superior comfort experience compared to visible wall-mounted mini-split heads or noisy traditional HVAC units. It provides high efficiency and features like a dehumidifier and washable filter that add to its value. However, its suitability is highly dependent on the ductwork requirements of the installation. It is specifically engineered for short, simple duct runs, and attempting to use it for a more extensive duct system will result in poor performance. The requirement for professional installation and matching with a compatible condenser and accessories also adds to the complexity and overall cost. For those with a straightforward application and a desire for a discreet, quiet system, the LG KNMKB091A is a strong contender, provided you are aware of the installation specifics and potential for limited customer support.