ML14KP1 MERIT™ SERIES
Single-Stage | Quantum™ Coil | R-454B | 3-Phase | 60Hz
COMMERCIAL PRODUCT SPECIFICATIONS (EHB)
HEAT PUMPS
3 to 5 Tons SEER2 up to 16.0 HSPF2 up to 8.2
Cooling Capacity | 35,400 to 58,000 Btuh Heating Capacity | 35,400 to 60,000 Btuh
2025 COMPLIANT REFRIGERANT
Model Number Identification
The model number ML14KP1-XXX-XXX is structured as follows:
- Product Tier: ML = Merit™ Series
- Nominal SEER2: 14 = 14.0
- Refrigerant: K = R-454B
- Unit Type: P = Heat Pump
- Cooling Stages: 1 = Single-Stage Compressor
- Nominal Cooling Capacity: 036 = 3 tons, 042 = 3.5 tons, 048 = 4 tons, 060 = 5 tons
- Voltage: 233 = 208/230V-3 phase-60Hz, 463 = 460V-3 phase-60Hz
- Ratings Revision Number
- Minor Revision Number
- Form Number: 211156 | June 2025
Feature Highlights
The unit features the following key components:
- 1. Outdoor Coil Fan: Direct drive PSC fan with vertical air discharge, louvered steel top fan guard, totally enclosed fan motor, ball bearings, and inherent motor protection.
- 2. Quantum™ Coil: Lennox designed and fabricated coil with enhanced aluminum alloy tube/enhanced fin construction for superior corrosion resistance. Features ripple-edged fins, aluminum tubes, lanced fins for maximum surface exposure, fin collars for maximum contact, flared shoulder tubing connections, and is factory tested and accessible for cleaning.
- 3. Expansion Valve - Outdoor Unit: Sized for heat pump systems, with a sensing bulb to monitor suction temperature during heating.
- 4. High Capacity Liquid Line Drier: Factory installed to trap moisture or dirt, utilizing a 100% molecular-sieve, bead type drier.
- 5. Four-Way Reversing Valve: Facilitates rapid changeover of refrigerant flow between cooling and heating modes, operating on pressure differential.
- 6. Scroll Compressor: High efficiency with uniform suction flow, constant discharge flow, and quiet operation due to low gas pulses. The compressor motor is internally protected, and a muffler reduces operating sound. It is mounted on resilient rubber for vibration-free operation.
- 7. Defrost Control: A time/temperature defrost control manages defrost cycles based on compressor runtime and outdoor coil temperature.
- 8. Heavy Gauge Steel Cabinet: Provides a durable enclosure with a pre-painted powder coat finish and louvered panels.
- 9. Refrigerant Line Access: Located for convenient access to refrigerant lines.
Approvals and Warranty
Approvals
- AHRI Standard 210-240-2023 certified
- AHRI Certified system match-ups and expanded ratings available at www.LennoxPros.com
- Sound rated to AHRI Standard 270-2008 test conditions
- Tested in Lennox' Research Laboratory environmental test room
- Rated According to U.S. Department of Energy (DOE) test procedures
- Unit and components ETL, NEC and CEC bonded for grounding to meet safety standards
- ETL certified (U.S. and Canada)
- ISO 9001 Registered Manufacturing Quality System
Warranty
- Compressor - Limited five years
- All other covered components - Limited one year
? Note: Refer to Lennox® Basic Limited Warranty at www.Lennox.com for additional details.
Features and Applications
Applications
- Available in 3 through 5 ton capacities.
- Offered in 208/230V or 460V-3ph models.
- Features sound levels as low as 76 dBA.
- Suitable for use with indoor air handlers or gas furnaces with indoor add-on coils.
- Shipped completely factory assembled, piped, and wired.
? Note: When heat pumps are used with gas furnaces, a dual-fuel compatible thermostat or zone control system with dual-fuel capabilities must be used (order separately).
Refrigeration System
R-454B Refrigerant
- Utilizes R-454B refrigerant, which has Low GWP (Global Warming Potential) and Zero ODP (Ozone Depletion Potential).
- R-454B is characterized by low toxicity and lower flammability (A2L classification).
- Units are factory pre-charged with refrigerant.
? Note: Total system refrigerant charge is dependent on outdoor unit size, indoor unit size, and refrigerant line length. Refer to the unit-mounted charging sticker to determine the correct amount of charge required.
Key Components and Features
Outdoor Coil Fan
- Direct drive PSC fan
- Vertical air discharge
- Louvered steel top fan guard
- Totally enclosed fan motor
- Ball bearings
- Inherently protected motor
Quantum™ Coil
- Lennox designed and fabricated
- Enhanced aluminum alloy tube/enhanced fin coil
- Superior corrosion resistance
- Ripple-edged aluminum fins
- Aluminum tube construction
- Lanced fins for maximum fin surface exposure
- Fin collars grip tubing for maximum contact area
- Flared shoulder tubing connections
- Factory tested under high pressure
- Entire coil is accessible for cleaning
Expansion Valve - Outdoor Unit
- Designed and sized for heat pump systems
- Sensing bulb senses suction temperature during heating cycle
High Capacity Liquid Line Drier
- Factory installed in the liquid line
- Drier traps moisture or dirt that could contaminate the system
- 100% molecular-sieve, bead type drier
Four-Way Reversing Valve
- Rapid changeover of refrigerant flow direction from cooling to heating and vice versa
- Operates on pressure differential between outdoor unit and indoor coil
Scroll Compressor
- High efficiency with uniform suction flow
- Constant discharge flow, high volumetric efficiency and quiet operation
- Low gas pulses during compression reduce operational sound levels
- Compressor motor is internally protected from excessive current and temperature
- Muffler in discharge line reduces operating sound levels
- Compressor is installed on resilient rubber mounts for vibration-free operation
Defrost Control
- Time/temperature defrost control
- Defrost cycle every 30, 60 or 90 minutes of compressor "on" time at outdoor coil temperatures below 42°F
- Factory setting: 90 minutes
- Anti-short cycle, timed-off control: 5 minutes
- Compressor delay: 30 seconds (field selectable)
- High and low pressure switch monitoring (five-trip lockout)
- Two diagnostic LEDs for troubleshooting
Cabinet
- Heavy gauge steel cabinet
- Pre-painted powder paint cabinet finish
- Louvered heavy gauge steel panels
- Control box conveniently located with all controls factory wired
- Corner patch plate allows compressor access
- Drainage holes provided in base section
- Zinc-Coated Steel Unit Base resists rust and corrosion
Refrigerant Line Connections, Electrical Inlets, Service Valves
- Sweat connection vapor and liquid lines
- Located on the corner of the unit cabinet
- Fully serviceable brass service valves
- Vapor valve can be fully shut off; liquid valve may be front seated to manage refrigerant charge while servicing
- Refrigerant line connections and field wiring inlets are located in one central area for easy access
- Braze-Free/Press Fitting Flexibility allows for installation versatility
Specifications
| Size | Nominal Tonnage | Sound Rating Number (dBA) | Connections (sweat) Liquid line (OD) - in. | Connections (sweat) Vapor line (OD) - in. | Refrigerant (15 ft. Line Set) R-454B charge furnished | Indoor Unit Expansion Valve (TXV) Order Number | Outdoor Coil Net face area - ft.² | Outdoor Coil Outer coil | Outdoor Coil Inner coil | Tube diameter - in. | Rows | Fins - in. | Outdoor Fan HP | Outdoor Fan Diameter - in. | Outdoor Fan Blades | Outdoor Fan Cfm | Outdoor Fan Rpm | Outdoor Fan Watts | Shipping Data - lbs. |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 036 | 3 | 75 | 3/8 | 7/8 | 7 lbs. 2 oz. | 26Z70 | 22.2 | 21.5 | 5/16 | 2 | 22 | 1/6 | 22 | 3 | 3590 | 839 | 200 | 220 | |
| 042 | 3.5 | 78 | 3/8 | 7/8 | 8 lbs. 5 oz. | 26Z71 | 24.93 | 24.13 | 5/16 | 2 | 22 | 1/3 | 22 | 3 | 4110 | 625 | 213 | 250 | |
| 048 | 4 | 79 | 3/8 | 7/8 | 8 lbs. 6 oz. | 26Z71 | 24.93 | 24.13 | 5/16 | 2 | 22 | 1/3 | 22 | 3 | 4110 | 825 | 213 | 250 | |
| 060 | 5 | 79 | 3/8 | 1-1/8 | 9 lbs. 6 oz. | 26Z72 | 29.09 | 28.16 | 5/16 | 2 | 22 | 1/3 | 22 | 3 | 4060 | 825 | 224 | 260 |
Electrical Data
| Line voltage data (Volts-3 Phase-60Hz) | 036 | 042 | 048 | 060 | ||||
|---|---|---|---|---|---|---|---|---|
| 208/230V | 460V | 208/230V | 460V | 208/230V | 460V | 208/230V | 460V | |
| Maximum overcurrent protection (MOCP) amps | 25 | 10 | 20 | 10 | 25 | 10 | 35 | 15 |
| Minimum circuit ampacity (MCA) | 15.4 | 7.4 | 12.3 | 6.5 | 16.4 | 7.9 | 20.4 | 9.1 |
| Compressor Rated Load Amps | 12.2 | 5.8 | 9.6 | 4.9 | 12.8 | 6.0 | 16.0 | 7.1 |
| Compressor Locked Rotor Amps | 97.5 | 44.3 | 90 | 36 | 120.4 | 49.4 | 156.4 | 69 |
| Fan Motor Full Load Amps | 1.4 | 1.4 | 2.6 | 2.6 | 2.6 | 2.6 | 2.6 | 2.6 |
? Note: Extremes of operating range are plus 10% and minus 5% of line voltage. HACR type breaker or fuse. Refer to National or Canadian Electrical Code manual for wire, fuse, and disconnect size requirements.
Optional Accessories
The following accessories can be ordered separately:
- Check/Expansion Valve Kits: Field installed on indoor units if required.
- Refrigerant Line Kits: Shipped refrigeration clean, dried, pressurized, and sealed. Suction line is insulated.
- Indoor Refrigerant Detection System (RDS): Complies with UL 60335-2-40. Required for R-454B systems. Detects R-454B refrigerant leaks and mitigates operation by stopping the compressor and running the blower until safe levels are reached.
- Compressor Crankcase Heater: Prevents liquid refrigerant migration and ensures proper compressor lubrication.
- Compressor Sound Cover: Reinforced vinyl cover with 1-1/2 inch thick fiberglass insulation.
- Freezestat: Senses suction line temperature and cycles the compressor off when it falls below a setpoint (opens at 29°F, closes at 58°F). Recommended with Low Ambient Kits.
- Indoor Blower Off Delay Relay Kit: Delays the indoor blower-off time during the cooling cycle.
- Low Ambient Kit (Fan Cycling): For cooling mode operation down to 45°F outdoor air temperature. Two options: 30°F (Kit 45F08) or speed control 0°F (Kit 18J42) (208/230V only).
- Mild Weather Kit: Allows heating operation above 75°F outdoor air temperature.
- Monitor Kit - Service Light
- Outdoor Thermostat Kit: Locks out electric heating elements on indoor units for two-stage control, maintaining low power input first.
- Unit Stand-Off Kit: Black high-density polyethylene feet to raise the unit off the mounting surface.
Optional Conventional Temperature Control Systems
CS7500 Commercial 7-Day Programmable Thermostat
- Features: Four-Stage Heating / Three-Stage Cooling, Universal Multi-Stage, Intuitive Touchscreen Interface, Automatic Changeover, Full Seven-Day Programming (Four Time Periods Per Day), Temperature and Humidity Control, One-Touch Away Mode, Holiday Scheduling, Smooth Setback Recovery (SSR), Performance Reports, Notifications/Reminders, Dehumidification Control, Economizer Relay Control, Backlit Display.
- Sensors/Accessories: Remote non-adjustable wall-mount 20k (24K41), Remote non-adjustable wall-mount 10k (47W36), Remote non-adjustable discharge air (duct mount) (47W37), Outdoor temperature sensor (19L22), Thermostat wall mounting plate (X2658).
CS3000 Commercial 5-2 Day Programmable Thermostat
- Features: Two-Stage Heating / Two-Stage Cooling, Conventional Systems, Intuitive Interface, 5-2 Day Programming, Program Hold, Remote Indoor Temperature Sensing, Smooth Setback Recovery (SSR), Economizer Relay Control, Maintenance/Filter/Service Reminders, Backlit Display.
- Sensors/Accessories: Remote non-adjustable wall mount 10k averaging (11Y05), Thermostat wall mounting plate (X2659), Universal Thermostat Guard with Lock (clear) (39P21).
Dimensions
Diagrams show top and side views of the unit with key dimensions labeled A (Width/Depth), B (Height), C (Depth), and electrical inlet locations.
| Size | A Width and Depth (in.) | A Width and Depth (mm) | B Height (in.) | B Height (mm) | C Depth (in.) | C Depth (mm) |
|---|---|---|---|---|---|---|
| 036 | 32-1/4 | 819 | 33-1/4 | 845 | 32-1/2 | 826 |
| 042 | 32-1/4 | 819 | 37-1/4 | 946 | 36-1/2 | 927 |
| 048 | 32-1/4 | 819 | 37-1/4 | 946 | 36-1/2 | 927 |
| 060 | 32-1/4 | 819 | 43-1/4 | 1099 | 42-1/2 | 1080 |
? Optional Unit Stand-Off Kit (4) is field installed.
Expanded Sound Data
The following table provides Octave Band Sound Power Levels (dBA) and estimated Sound Pressure Levels at various distances.
| Size | Sound Rating Number (dBA) | Center Frequency - HZ (125) | Center Frequency - HZ (250) | Center Frequency - HZ (500) | Center Frequency - HZ (1000) | Center Frequency - HZ (2000) | Center Frequency - HZ (4000) | Center Frequency - HZ (8000) | Estimated Sound Pressure Level at 3 ft. (dBA) | Estimated Sound Pressure Level at 5 ft. (dBA) | Estimated Sound Pressure Level at 10 ft. (dBA) | Estimated Sound Pressure Level at 15 ft. (dBA) | Estimated Sound Pressure Level at 50 ft. (dBA) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 036 | 75 | 59 | 68 | 71.5 | 68.5 | 66 | 61 | 54 | 68 | 63 | 57 | 54 | 43 |
| 042 | 78 | 62 | 71.0 | 74.5 | 72.5 | 70 | 63 | 55.5 | 71 | 66 | 60 | 57 | 46 |
| 048 | 79 | 61 | 70.5 | 75.5 | 73.0 | 70 | 64 | 56.0 | 72 | 67 | 61 | 58 | 47 |
| 060 | 79 | 61.5 | 70.0 | 73.0 | 71 | 71 | 68 | 63 | 73 | 68 | 62 | 59 | 48 |
? Note: Octave sound power data does not include tonal correction. Estimated sound pressure levels are based on AHRI Standard 275-2010 for equipment on the ground/roof with no adjacent reflective surface within 9.8 feet. Sound pressure levels may increase based on different assumptions.
Installation Clearances
Diagrams illustrate required clearances around the unit for service and installation.
- Service Clearance: 30 in. (762 mm) on one side adjacent to the Control Box.
- Other Sides: One side must have 36 in. (914 mm), one may have 12 in. (305 mm), and the remaining side may have 6 in. (152 mm).
- Top of Unit: 48 in. (1219 mm) clearance required.
- Between Units: 24 in. (610 mm) clearance required between two units.
TXV Usage and Substitution
All Lennox coils and air handlers are shipped with a factory installed TXV. If a different size TXV is required, it must be ordered separately and field installed.
TXV Usage
| Size | Order Number |
|---|---|
| 036 | 26Z70 |
| 042 | 26Z71 |
| 048 | 26Z71 |
| 060 | 26Z72 |
TXV Substitution - R-454B
This table provides a guide for replacing the factory installed R-454B TXV when the indoor unit size differs from the outdoor unit size.
| Outdoor Unit Size (Tons) | Indoor Unit Size (Tons) | TXV Furnished | TXV Replacement |
|---|---|---|---|
| 036 (3) | 42 (3.5) | 26Z71 | 26Z70 |
| 036 (3) | 48 (4) | 26Z71 | 26Z70 |
| 036 (3) | 49 (4) | 26Z71 | 26Z70 |
| 036 (3) | 50/60 (4/5) | 26Z71 | 26Z70 |
| 036 (3) | 51/61 (4/5) | 26Z71 | 26Z70 |
| 036 (3) | 60 (5) | 26Z72 | 26Z70 |
| 042 (3.5) | 24 (2) | 26Z70 | 26Z71 |
| 042 (3.5) | 30 (2.5) | 26Z70 | 26Z71 |
| 042 (3.5) | 30/36 (2.5/3) | 26Z70 | 26Z71 |
| 042 (3.5) | 36 (3) | 26Z70 | 26Z71 |
| 042 (3.5) | 60 (5) | 26Z72 | 26Z71 |
| 048 (4) | 30/36 (2.5/3) | 26Z70 | 26Z71 |
| 048 (4) | 36 (3) | 26Z70 | 26Z71 |
| 048 (4) | 60 (5) | 26Z72 | 26Z71 |
| 060 (5) | 50/60 (4/5) | 26Z71 | 26Z72 |
| 060 (5) | 51/61 (4/5) | 26Z71 | 26Z72 |
TXV Ranges:
- 26Z70: 1.5 to 3 ton systems - Use on 3 ton (036) and lower systems.
- 26Z71: 3.5-4 ton systems - Use on 4 ton (048) and down to 3.5 ton (042) systems.
- 26Z72: 5 ton systems - Use on 5 ton (060) systems only.
Revisions
- Specifications Updated for mixed product.
Contact Information
- Visit Lennox at www.lennox.com
- For the latest technical information: www.LennoxCommercial.com
- Contact: 1-800-4-LENNOX
? Note: Due to Lennox' ongoing commitment to quality, Specifications, Ratings and Dimensions are subject to change without notice and without incurring liability. Improper installation, adjustment, alteration, service or maintenance can cause property damage or personal injury. Installation and service must be performed by a qualified installer and servicing agency.
© 2025 Lennox Industries, Inc.
