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2015 Lennox Industries Inc.
Corp. 1244-L9
Revised January 12, 2015
MS8 SERIES
INSTALLATION AND SERVICE
PROCEDURES
MS8 SERIES UNITS — MINI-SPLIT SINGLE-ZONE SYSTEMS (208-230V)
MS8-CO Air Conditioner Outdoor Unit
MS8-HO Heat Pump Outdoor Unit
MS8-CI Air Conditioner Indoor Unit
MS8-HI Heat Pump Indoor Unit
Wireless
Remote Control
(furnished)
CAUTION
Physical contact with metal edges and corners while
applying excessive force or rapid motion can result in
personal injury. Be aware of, and use caution when
working near these areas during installation or while
servicing this equipment.
WARNING
Improper installation, adjustment, alteration, service or
maintenance can cause personal injury, loss of life, or
damage to property.
Installation and service must be performed by a licensed
professional installer (or equivalent) or a service agency.
IMPORTANT
The Clean Air Act of 1990 bans the intentional venting of
refrigerant (CFCs, HCFCs and HFCs) as of July 1, 1992.
Approved methods of recovery, recycling or reclaiming
must be followed. Fines and/or incarceration may be
levied for noncompliance.
IMPORTANT
These units must be installed as a matched system as
specified in the Lennox Engineering Handbook.
TABLE OF CONTENTS
I. OVERVIEW
Shipping and Packing List 2......................
Required Tools and Supplies 3....................
Specifications 4.................................
Model Number Identification 6....................
Unit Dimensions and Weights 6...................
Typical System Component Setup 6...............
II. INSTALLATION
General 8......................................
Clearances 8...................................
Torque Requirements for Caps and Fasteners 8....
Setting Outdoor Unit 8...........................
Repositioning Indoor Air Temperature Sensor 10.....
Indoor Unit Placement and Preparation 10..........
Indoor Unit Cable Connections 14..................
Securing Indoor Unit to Wall Mounting Bracket 15....
Outdoor Unit Cable Connections 16................
Operating Service Valves 19.......................
Line Set Requirements 20.........................
Leak Test and Evacuation 22......................
Unit Start-Up 23.................................
Adding Refrigerant for Longer Line Sets 23..........
Checking Large Line Operating Pressures 23........
Wrapping Bundle 25..............................
Maintenance 26....................................
III. OPERATING THE WIRELESS REMOTE
IV. SYSTEM OPERATION AND SERVICE
System Operational Modes 35.......................
System Functions 43...............................
System Protection Features 44......................
Other Functions 46.................................
Temperature Sensors (location, function and
troubleshooting 47.................................
Indoor and Outdoor Control Parts Identifications 53.....
Indoor and Outdoor Error Codes 57..................
Refrigerant System Flow Diagrams 66................
Typical Unit Wiring Diagrams 67...................
Troubleshooting 72.................................
Major System Components 81.......................
Optional Condensate Pump Wiring Connection 88...........
Disassembly Procedures 88.........................
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