Mitsubishi Electric 3.5 Ton 42,000 BTU Multi-zone Ductless Mini Split Hyper Heat Pump Condenser R454B Refrigerant | MXZ-SM42NLHZ

Overview

The Mitsubishi Electric MXZ-SM42NLHZ is a 42,000 BTU/H Hyper Heat Pump outdoor unit designed to operate as a multi-zone heat pump system with compatible indoor units. It provides 42,000 Btu/h rated cooling capacity and 48,000 Btu/h rated heating capacity at 47°F under the published rating conditions, supporting non-ducted, mixed, or ducted indoor configurations. Published efficiency varies by indoor configuration, with SEER2 listed at 21.50 (non-ducted), 19.50 (mixed), and 17.50 (ducted), and HSPF2 (IV) listed at 11.10, 10.55, and 10.00. The unit uses R454B refrigerant and ships with a 6 lb 10 oz pre-charged refrigerant amount to support system piping within the listed limits. Electrical requirements are 208/230V, single-phase, 60 Hz with a guaranteed voltage range of 198–253V. For system layout flexibility, it supports up to 12 connected indoor units without a branch box or up to 5 indoor units when using a branch box. Refrigerant connections are 0.38 in liquid and 0.63 in gas, with total piping length up to 492 ft to accommodate larger or multi-level layouts.

Performance

Cooling performance is rated at 42,000 Btu/h with a minimum cooling capacity of 14,000 Btu/h, enabling capacity modulation for part-load conditions. Heating performance is rated at 48,000 Btu/h at 47°F, with rated heating capacity at 17°F listed as 34,000 Btu/h for non-ducted, 33,000 Btu/h for mixed, and 32,000 Btu/h for ducted indoor arrangements. At 5°F and -13°F, the unit lists a 48,000 Btu/h maximum heating capacity with published maximum power input values for each indoor configuration category. Capacity control is driven by an INVERTER-driven compressor with a twin rotary compressor type, a listed compressor model MRK53FFJMC-L, and a 3 kW compressor motor output. Outdoor airflow is handled by dual fan motors with a combined fan motor output of 200 W + 200 W, supporting stable coil heat transfer across operating conditions. For cold-weather operation, defrost is managed by a reverse-cycle defrost method and the heat exchanger includes Blue Fin coating.

Smart Features

Multi-zone zoning is enabled through compatibility with M-Series, P-Series, and CITY MULTI indoor units, allowing a single outdoor unit to serve multiple indoor zones. System design can be configured with a branch box for up to 5 indoor units, or without a branch box for up to 12 indoor units, supporting a wide range of room-by-room control layouts. The published performance table includes non-ducted, mixed, and ducted connection categories, helping designers match indoor unit types to the required cooling and heating output. A listed 230V indoor-to-outdoor S1–S2 control voltage supports standard Mitsubishi interconnect wiring between indoor units and the outdoor unit. Thermal Differential is listed at 1°F when used with the PAC-MKA32/52BC control, supporting tighter temperature control when that control option is specified. The accessory list includes optional alarm kit and alarm kit interface components for systems that require external alarm signaling.

Comfort & Noise

Sound performance is listed at 50 dB(A) in cooling and 54 dB(A) in heating, supporting outdoor placement near occupied areas when code and site conditions allow. The INVERTER-driven compressor modulates output to meet load, which can reduce frequent start-stop cycling compared with fixed-capacity operation. Because the system can serve multiple indoor units, comfort delivery can be distributed across zones instead of relying on a single airflow path for the entire building. A built-in base pan heater supports defrost drainage management during heating operation in low outdoor temperatures. Heating intake air operation is listed down to -13°F, and the heating thermal lock-out and restart temperatures are listed at -24°F and -14°F. These operating limits help maintain predictable heating behavior during cold weather events where outdoor temperature swings are common.

Use Case Fit

This system is designed and intended for residential, commercial, and light-industrial environments, making it suitable for mixed-use projects that need zoned heat pump comfort. With up to 492 ft of total refrigerant piping and maximum height differences up to 164 ft when the outdoor unit is above the indoor units, it can support multi-story layouts and long-run installations within the published constraints. Cooling intake air temperature is listed from 23°F to 115°F DB, supporting shoulder-season operation and higher ambient cooling conditions. Heating intake air temperature is listed from -13°F to 70°F DB, supporting heating operation in cold-climate regions where extended low-ambient performance is required. The unit supports non-ducted, mixed, and ducted indoor configuration categories, allowing the same outdoor platform to be applied across apartments, offices, and light commercial tenant spaces. For retrofit work, published minimum connected capacity requirements help align indoor unit selection to the outdoor unit’s operating range.

Value & Reliability

Reliability features include compressor overcurrent detection, compressor thermal protection, fan motor overheating and voltage protection, and high-pressure protection to help safeguard critical components. The heat exchanger and base panel include Seacoast protection rated for 2,000 hours in ASTM B117 testing, along with Blue Fin heat exchanger coating for additional corrosion resistance. Electrical robustness is supported by a guaranteed voltage range of 198–253V and a 5 kA short-circuit current rating (SCCR). A built-in base pan heater is included to help manage condensate and ice during heating operation in low ambient conditions. The unit ships with a 6 lb 10 oz pre-charged refrigerant amount of R454B, reducing the amount of initial charge work required within the specified piping limits. Published recommended breaker and fuse sizes are provided for branch-box and non-branch-box system architectures to support consistent field protection design.

Summary Wrap-Up

For buyers who need multi-zone heating and cooling from a single outdoor platform, the MXZ-SM42NLHZ pairs 42,000 Btu/h rated cooling with 48,000 Btu/h rated heating at 47°F and documented low-ambient heating capability. It uses R454B refrigerant and a twin rotary INVERTER-driven compressor to deliver variable capacity operation across a broad outdoor temperature range. Connection flexibility supports up to 12 indoor units without a branch box or up to 5 indoor units with a branch box, enabling room-by-room zoning in residential and light commercial layouts. Outdoor sound pressure levels are listed at 50 dB(A) in cooling and 54 dB(A) in heating, balancing capacity with site-friendly acoustics. The outdoor unit cabinet measures 41.34 in wide by 13.00 in deep by 52.69 in high and has a listed unit weight of 283 lb for planning and handling. For contractors and wholesale customers, the published electrical, piping, and protection specifications provide a clear path to integrate this system into new construction or retrofit designs.

Key Features

• 42,000 Btu/h rated cooling capacity: Provides 42,000 Btu/h rated cooling output at 95°F test conditions for multi-zone comfort cooling.
• 48,000 Btu/h rated heating capacity at 47°F: Delivers 48,000 Btu/h rated heating output at 47°F for heat pump operation in cold-weather seasons.
• R454B refrigerant charge: Uses R454B refrigerant with a 6 lb 10 oz pre-charged amount to support system piping within published limits.
• Twin rotary INVERTER-driven compressor: Modulates capacity to maintain temperature set point with a twin rotary compressor and INVERTER drive control.
• Indoor unit connection capacity: Supports up to 12 connected indoor units without a branch box or up to 5 with a branch box for zoned layouts.
• Operating temperature range: Lists cooling intake air temperatures from 23°F to 115°F DB and heating intake air temperatures from -13°F to 70°F DB, with heating thermal lock-out and restart at -24°F and -14°F.
• Sound pressure levels: Lists 50 dB(A) sound pressure in cooling and 54 dB(A) in heating for exterior placement planning.