Lennox MS8 SERIES Installation And Service Procedures
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Lennox MS8 SERIES Installation And Service Procedures

Lennox MS8 SERIES Installation And Service Procedures

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Corp. 1244-L9
Revised January 12, 2015
MS8 SERIES UNITS - MINI-SPLIT SINGLE-ZONE SYSTEMS (208-230V)
MS8-CO Air Conditioner Outdoor Unit
MS8-HO Heat Pump Outdoor Unit
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.
INSTALLATION AND SERVICE
PROCEDURES
MS8-CI Air Conditioner Indoor Unit
MS8-HI Heat Pump Indoor Unit
Wireless
Remote Control
(furnished)

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  • Page 1: Table Of Contents

    INSTALLATION AND SERVICE PROCEDURES Corp. 1244-L9 Revised January 12, 2015 MS8 SERIES UNITS — MINI-SPLIT SINGLE-ZONE SYSTEMS (208-230V) TABLE OF CONTENTS I. OVERVIEW Shipping and Packing List ..... .

  • Page 2: Overview

    I. OVERVIEW Shipping and Packing List Check the unit components for shipping damage. If you find any damage, immediately contact the last carrier. 1 — ASSEMBLED INDOOR UNIT The assembled indoor unit will include the following items: Part Picture Part Picture Part Name Name Name 1/4”...

  • Page 3: Required Tools And Supplies

    Adjustable wrench Level A 5/16” female flare to 1/4” male flare adapter Micron gauge (order Lennox catalog number Y0576) SUPPLIES The following field-provided supplies may be required for installation Line set (see table 9 for requirements) Foam insulation (line set and condensate line) UV rated protective tape (used to maintain positioning of bundle).

  • Page 4: Specifications

    Specifications - AIR CONDITIONER SYSTEMS OUTDOOR UNIT Nominal Tonnage 0.75 Outdoor Unit Model No. MS8­CO­09P MS8­CO­12P MS8­CO­18P MS8­CO­24P Small line o.d. ­ flare Connections (in.) Large line o.d. ­ flare Ambient Temperature Operating Range ­ °F 0 ­ 109 0 ­ 109 5 ­...
  • Page 5 Specifications - HEAT PUMP SYSTEMS OUTDOOR UNIT Nominal Tonnage 0.75 Outdoor Unit Model No. MS8­HO­09P MS8­HO­12P MS8­HO­18P MS8­HO­24P MS8­HO­30P Small line o.d. ­ flare Connections (in.) Large line o.d. ­ flare Cooling 0 ­ 109 0 ­ 109 14 ­ 109 14 ­...

  • Page 6: Model Number Identification

    Model Number Identification − −09 Minor Revision Series Type MS = Mini-Split Number of Zones 1 = single zone Series Unit Type Voltage CI = Air Conditioner Indoor Unit L = 115V-1phase-60hz HI = Heat Pump Indoor Unit CO = Air Conditioner Outdoor Unit Capacity - BTUH HO = Heat Pump Outdoor Unit 09 = 9,000...

  • Page 7: Typical System Component Setup

    TABLE 3. OUTDOOR UNIT DIMENSIONS — INCHES (MILLIMETERS) Typical System Component Setup TYPICAL COMPONENT SETUP RETURN AIR INDOOR UNIT TAPE REFRIGERANT LINE SET, CONDENSATE LINE DISPLAY AND INDOOR / OUTDOOR CABLE INDICATORS IMPORTANT - The refrigerant metering device for this system is COOL SUPPLY AIR located in the outdoor unit.

  • Page 8: Ii. Installation

    Using an Allen wrench rated at less than 50Rc risks rounding or breaking off the wrench, or stripping the valve stem recess. See the Lennox Service and Application Notes #C-08-1 for further details and information. TABLE 5 INSTALL UNIT AWAY...

  • Page 9: Setting Outdoor Unit

    Setting Outdoor Unit NOTICE OUTDOOR UNIT POSITIONING CONSIDERATIONS Roof Damage! (AIR CONDITIONER OR HEAT PUMP) This system contains both refrigerant and oil. Some Consider the following when positioning the unit: rubber roofing material may absorb oil. This will cause Some localities are adopting sound ordinances based the rubber to swell when it comes into contact with oil.

  • Page 10: Repositioning Indoor Air Temperature Sensor

    PREVAILING WINDS (HEAT PUMP ONLY) AVOID 1. Direct sunlight if possible. If unit coil cannot be installed away from prevailing winter 2. Locating unit less than 3-1/4” (1 meter) away from winds, a wind barrier should be constructed. Size barrier at combustible materials and vapors.
  • Page 11 NOTE — If opposite-side exit is preferred, see figure 18 to determine the exit point for the line set, condensate line switch condensate line and drain cap. and indoor / outdoor cable (figure 11). 3. Use the wall mounting bracket as a template to CONDENSATE / REFRIGERANT PIPING REAR EXIT LOCATIONS 21-5/16”...
  • Page 12 40-1/8” (1018) 7-7/16” 27 (685) (189) 24 kBtu 2-9/16” 2-9/16” (65) (65) 1-3/4” (45) 22-5/8” (575) 2-1/2” 3-1/2” (65) 1-7/16” (36) (90) 30 kBtu 1” (25) 2-9/16” 2-9/16” (65) (65) 1“ (25) 4” 4” (102) (102) FIGURE 12 INSTALLING WALL SLEEVE BORING HOLE FOR WALL SLEEVE 1.
  • Page 13 at a slight angle 1/4” (6 mm) shorter than the thickness NOTE It is important to use all screws provided to secure — of the wall. the wall mounting bracket to the wall. Additional holes may be drilled through the metal wall mounting bracket to better secure wall bracket to wall studs.

  • Page 14: Indoor Unit Cable Connections

    1. Confirm proper slope (not less than 1/4 inch per foot) CHANGING CONDENSATE DRAIN LOCATION and routing of condensate lines to ensure moisture is (IF NECESSARY) drained away from the indoor unit (see page 12). 1. Locate the condensate line and the drain cap 2.

  • Page 15: Securing Indoor Unit To Wall Mounting Bracket

    FEED CABLE THROUGH WALL TYPICAL INDOOR UNIT INDOOR UNIT) — SECURING CABLE / WIRES INDOOR UNIT WALL MOUNTING BRACKET WALL CONDUIT ROUTING GUIDE REAR VIEW OF INDOOR UNIT WIRING FIGURE 22 FIELD-PROVIDED 5. Strip the wire insulation to expose the stranded wire. PVC WALL SLEEVE 6.

  • Page 16: Outdoor Unit Cable Connections

    FEED BUNDLE THROUGH WALL SLEEVE CONNECTING CONDENSATE LINE UPPER MOUNTING HOOKS PASS BUNDLE THROUGH WALL FIGURE 27 3. Use tape approved waterproofing line FIGURE 24 connections to secure the field-provided pipe to the factory-installed condensate line. 1. Secure the indoor unit to the wall bracket using the TAPING CONDENSATE LINE CONNECTION lower mounting hooks.
  • Page 17 NOTE — Stranded wire must be used to connect the OUTDOOR UNIT outdoor unit to the indoor unit. The stranded wire is COMMUNICATION necessary to ensure proper system communication and operation. N(1) 2 3 L1 L2 SUPPLY POWER Size per unit nameplate and local and national codes. WIRING CONNECTIONS 1.
  • Page 18 TABLE 6 TABLE 7 WIRE COLOR CODES SYMBOLS COLOR CODE CODE CODE COLOR COLOR SYMBOL PARTS NAME OR SYMBOL REACTOR (CHOKE) WHITE BROWN PCB1-PCB2 PRINTED CIRCUIT BOARD YELLOW BLUE S10/S11S40/S70/S80/S90 CONNECTOR BLACK OVERLOAD YELLOW YEGN GREEN COMP COMPRESSOR Table 8. Valve Caps Torque Recommendations 11 12 Outside Diameter Recommended Torque...

  • Page 19: Operating Service Valves

    Operating Service Valves IMPORTANT The large line service valve on the outdoor unit is used to To prevent stripping of the various caps, use an purge air, test for leaks, check operating pressures and add appropriately sized wrench and fit the wrench snugly over refrigerant to system.

  • Page 20: Line Set Requirements

    connections and sizes as listed in table 12. TIGHTENING SERVICE VALVE CAPS Seal and isolate the opening where the bundle (including To Access Service Port: refrigerant lines) passes through so vibration is not transmitted to the building. Pay close attention to line set A service port cap protects the service port core TURN isolation during installation of any HVAC system.
  • Page 21 TABLE 9 REFRIGERANT LINE SET REQUIREMENTS, LENGTH AND HEIGHT LIMITATIONS AND OUTDOOR UNIT REFRIGERANT METERING DEVICE TYPE (AIR CONDITIONER AND HEAT PUMP SYSTEMS) System Line Set Diameters Refrigerant Maximum Line Set Maximum Line Set Size Metering Device Length Elevation Small Line Large Line Type (kBtu)

  • Page 22: Leak Test And Evacuation

    MAKING CONNECTIONS AT INDOOR UNIT FLARING TOOLS (MALE TO FEMALE CONNECTION) APPLY REFRIGERANT LUBRICANT HERE WING NUT TYPE CLUTCH TYPE FIGURE 36 MALE FLARE CONNECTION TYPICAL LINE SET CONNECTION TO FIGURE 38 OUTDOOR UNIT 4. Tighten flare nuts. Do not over-tighten a flared joint. 2-WAY LARGE LINE Once snug, continue another half turn on each nut.

  • Page 23: Unit Start-Up

    12 for general guides. Minor variations in these pressures may be expected due to differences in installations). FV50S PVE is the ONLY acceptable oil for Lennox MS7 and MS8 mini-split systems. IMPORTANT If the operating pressures do not fall within the ranges given...
  • Page 24 MANIFOLD GAUGE SET CONNECTIONS FOR LEAK TESTING, EVACUATION AND CHARGING HIGH MICRON GAUGE (REQUIRED FOR MANIFOLD GAUGE SET EVACUATION A34000 1/4 SAE TEE WITH PROCEDURE ONLY) SWIVEL COUPLER VACUUM NITROGEN PUMP HFC-410A FIGURE 40 TABLE 12 LINE SET LENGTH AND ADDING REFRIGERANT System Temperature Condition ºF (ºC) Indoor...

  • Page 25: Wrapping Bundle

    Wrapping Bundle CONTROL WIRING BUNDLING After system has been tested for leaks and proper INSULATE AND TAPE LINE operation has been verified, use tape to bundle the control wiring, line set and condensate line. WRAP WITH VINYL TAPE CONTROL WIRING (NARROW) 1.

  • Page 26: Maintenance

    3. An optional field-provided exterior wall channel may be Maintenance used in lieu of taping the utility bundle (see figure 48) to protect the bundle from UV rays, weather, etc. OUTDOOR UNIT 1. Ensure power is off before cleaning. OPTIONAL EXTERIOR WALL CHANNEL 2.

  • Page 27: Iii. Operating The Wireless Remote

    III. OPERATING THE WIRELESS REMOTE Wireless Remote Functions The wireless remote control provides system control to the homeowner at the touch of a button. The indoor unit and remote control send information back and forth continuously. The remote control must be placed on a table or other surface in direct line of sight with the indoor unit infrared receiver.
  • Page 28 Wireless Remote Functions (Continued) SWITCH FROM °C TO °F With system OFF, press MODE and - buttons simultaneously to switch from Centigrade to Fahrenheit. Current selection is displayed to the right of the temperature display. CLOCK button Use the CLOCK button to adjust LOUVER SETTING button the time displayed on the remote See page for complete details on...
  • Page 29 Wireless Remote Functions (Continued) LOUVER SETTING button To return the louver to the default position, press the Use the LOUVER SETTING LOUVER SETTING button button to choose a preferred LOUVER until the icon disappears. SETTING setting for the indoor unit ICON directional louver.
  • Page 30 Wireless Remote Functions (Continued) REMOTE LOCK Press - and + buttons simulta­ neously to either lock or unlock the remote control buttons. When TIMER ON button locked, the icon is Use the TIMER ON button to ini­ displayed. tiate or cancel a single timed-on event.

  • Page 31: System Start Up Using Wireless Remote

    System Start Up Using Wireless Remote General Operation 1 - Press POWER button once to turn system on. 2 - Press MODE button until desired operating mode icon is displayed. NOTE - When AUTO mode is selected, the temperature setting is not displayed on the remote control.
  • Page 32 Remote Control Batteries The wireless remote control requires two AAA, 1.5V batteries. DO NOT attempt to use any other type of battery. Follow the steps below and in the illustrations to replace the batteries when necessary. 1 - Remove screw that secures the battery access panel to the remote.
  • Page 33 Auto ON Switch If the remote control is lost or damaged, or if AUTO Switch charged AAA, 1.5V batteries are not available, (Recessed) the Auto ON switch can be used to turn the AUTO system on or off. The Auto ON switch is located behind the cov­ er panel on the indoor unit.
  • Page 34 SHOCK HAZARD! DO NOT SPRAY water into outdoor unit. Failure to follow this warning could lead to electrical shock, resulting in personal injury or death. Lennox recommends annual inspection by a licensed professional service technician, or equiva­ lent. Page 34...

  • Page 35: Iv. System Operation And Service

    IV. SYSTEM OPERATION AND SERVICE SYSTEM OPERATIONAL MODES Air conditioner systems have four modes of operation. Heat pumps have five operational modes. These modes are: Auto Cooling Dehumidification Heat (HP model only) AUTO MODE Auto Mode - Non-adjustable indoor temperature set points are 68F°and 77°F (20°C and 25°C) NOTE —...
  • Page 36 COOLING MODE (I FEEL MODE OFF) Cool Mode - Indoor temperature set point range is 61°F and 86°F (16°C and 30°C) NOTE — Reversing valve is de-energized in cooling mode. COOLING MODE FIGURE 50 Protective Functions Delays that normally protect the compressor are disabled during defrost cycles: 1.
  • Page 37 COOLING MODE (I FEEL MODE ON) Cool Mode - Indoor temperature set point range is 61°F and 86°F (16°C and 30°C) NOTE — Reversing valve is de-energized in cooling mode. COOLING MODE FIGURE 52 Protective Functions Delays that normally protect the compressor are disabled during defrost cycles: 1.
  • Page 38 DEHUMIDIFICATION MODE (I FEEL MODE OFF) Dehumidification Mode - Indoor temperature set point range is 61°and 86°F (16°C and 30°C) DEHUMIDIFICATION MODE FIGURE 54 Protective Functions Delays that normally protect the compressor are disabled during defrost cycles: 1. Minimum three (3) minute compressor time delay between operating cycles. 2.
  • Page 39 DEHUMIDIFICATION MODE (I FEEL MODE ON) Dehumidification Mode - Indoor temperature set point range is 61°F and 86°F (16°C and 30°C) DEHUMIDIFICATION MODE FIGURE 55 Protective Functions Delays that normally protect the compressor are disabled during defrost cycles: 1. Minimum three (3) minute compressor time delay between operating cycles. 2.
  • Page 40 HEAT MODE (I FEEL MODE OFF) Heat Mode - Indoor temperature set point range is 61°F and 86°F (16°C and 30°C) NOTE — Reversing valve is energized in heating mode. HEATING MODE FIGURE 56 Protective Functions Delays that normally protect the compressor are disabled during defrost cycles: 1.
  • Page 41 HEAT MODE (I FEEL MODE ON) Heat Mode - Indoor temperature set point range is 61°F and 86°F (16°C and 30°C) NOTE — Reversing valve is energized in heating mode. HEATING MODE FIGURE 57 Protective Functions Delays that normally protect the compressor are disabled during defrost cycles: 1.
  • Page 42 DEFROST MODE (HEAT PUMP ONLY) The front panel indicator will display an H1 code when the system is in defrost. The system will perform as indicated in the figure 58. DEFROST MODE FIGURE 58 Protective Functions Delays that normally protect the compressor are disabled during defrost cycles: 1.

  • Page 43: System Functions

    SYSTEM FUNCTIONS These systems have several functions which are addressed in this section. These functions are: Sleep Turbo Cold Blow Prevention (Heat Pumps Only) SLEEP Cooling or Dehumidification — Sleep Function When sleep function has been set properly , the setpoint will be increased by 1.8°F (1°C) after the sleep function has run for 1 hour, will be increased by another 1.8°F (1°C) after 2 hours and increased by another 1.8°F (1°C) after 3 hours.

  • Page 44: System Protection Features

    COLD BLOW PREVENTION This function prevents cold air from blowing into space in heating mode. After a three (3) minute time delay, one of the following two indoor fan cycles occurs: 1. When the following conditions are met: A. Indoor ambient temperature is greater than 75°F (24°C). B.
  • Page 45 INTELLIGENT POWER MODULE (IPM) PROTECTION (H5) The IPM module, which is an integrated part of the outdoor control, protects the system from the following conditions: High ambient temperatures Loss of cooling to the heat sink Low voltage Loose heat sink to control board An inverter drive (VFD) works by taking AC mains (single or three phase) and first rectifying it into DC.

  • Page 46: Other Functions

    OUTDOOR COIL HIGH TEMPERATURE PROTECTION FIGURE 61 COMMUNICATION FAULT (E6) If either the indoor or outdoor controls are unable to communicate with each other for a minimum of three minutes, the system will stop and an error code is displayed on the indoor unit. OUTDOOR UNIT CONTROL PROTECTION When excessive temperature is sensed at the outdoor unit control, the compressor will stop.

  • Page 47: Temperature Sensors

    TEMPERATURE SENSORS (LOCATION, FUNCTION AND TROUBLESHOOTING) Refer to tables 15, 16 and 17 for sensor resistance valves and figure 63 for location of sensors. INDOOR UNIT 1. Indoor Air Temperature Sensor (RT1): This sensor measures the return air temperature coming into the indoor coil and sends this information to the indoor and outdoor controls.
  • Page 48 DISCHARGE LINE TEMPERATURE SENSOR (RT5) High compressor discharge temperature can result from either of the following conditions: Low refrigerant charge Restricted refrigerant flow When the discharge line temperature drops below 194°F (90°C) and the compressor has been OFF for more than 3 minutes, the system will resume normal operation.The discharge line sensor continuously monitors the discharge temperature and communicates this to the microprocessor.
  • Page 49 TABLE 15 INDOOR AND OUTDOOR AMBIENT SENSOR RESISTANCE VALUES (15K) — ºF (ºC) Temp.(°F) Resistance(kΩ) Temp.(°F) Resistance(kΩ) Temp.(°F) Resistance(kΩ) Temp.(°F) Resistance(kΩ) -2.2 138.1 18.75 138.2 3.848 208.4 1.071 -0.4 128.6 69.8 17.93 3.711 210.2 1.039 121.6 71.6 17.14 141.8 3.579 1.009 73.4 16.39...
  • Page 50 TABLE 16 INDOOR AND OUTDOOR COIL SENSOR RESISTANCE VALUES (20K) — ºF (ºC) Appendix 2: Resistance Table of Outdoor and Indoor Tube Temperature Sensors(20K) Temp.(°F) Resistance(kΩ) Temp.(°F) Resistance(kΩ) Temp.(°F) Resistance(kΩ) Temp.(°F) Resistance(kΩ) -2.2 181.4 25.01 138.2 5.13 208.4 1.427 -0.4 171.4 69.8 23.9...
  • Page 51 TABLE 17 OUTDOOR DISCHARGE LINE SENSOR RESISTANCE VALUES (50K) — ºF (ºC) Temp.(°F) Resistance(kΩ) Temp.(°F) Resistance(kΩ) Temp.(°F) Resistance(kΩ) Temp.(°F) Resistance(kΩ) -20.2 853.5 120.2 18.34 190.4 4.754 -18.4 799.8 51.8 93.42 17.65 192.2 4.609 -16.6 53.6 89.07 123.8 16.99 4.469 -14.8 703.8 55.4 84.95...
  • Page 52 FIGURE 63 Page 52 MS8C / MS8H (208-230V)

  • Page 53: Indoor And Outdoor Control Parts Identifications

    Indoor and Outdoor Control Parts Identifications INDOOR CONTROLS TYPICAL INDOOR UNIT CONTROL (9 - 12 KBTU) Jumper Cap Terminal FIGURE 64 TYPICAL INDOOR UNIT CONTROL (18 KBTU) FIGURE 65 Page 53 Corp. 1244-L9...
  • Page 54 TYPICAL 24 KBTU INDOOR UNIT CONTROL (208-230V) 1. Ground terminal. 2. DC fan motor terminal 3. Louver Up/Down motion terminal. 4. Not used. 5. Display terminals 6. Indoor temperature sensor input 7. Indoor coil temperature sensor input 8. Indoor/outdoor communication terminal 9.
  • Page 55 OUTDOOR CONTROLS TYPICAL 9-12 KBTU OUTDOOR CONTROLS (208-230V) 7 8 9 11 1. Neutral 9. Reversing valve interface 2. Power line input 10. Reversing valve power 3. Communications interface 11. Heat tape wiring 4. Reactor interface 1 12. Overload input 5.
  • Page 56 TYPICAL 30 KBTU OUTDOOR CONTROLS (208-230V) 1. T1 transformer. 2. Overload protection terminal (OVC-COMP) 3. Thermal package terminals (CN2) 4. High voltage protection ter­ minals (HPP) 5. Expansion valve terminal (EV) 6. High voltage protection ter­ minal (HPP1) 7. Reversing valve terminal 8.

  • Page 57: Indoor And Outdoor Error Codes

    Indoor and Outdoor Error Codes This section identifies error codes that appear on the front panel of the indoor unit or outdoor unit control. Many of the error codes will automatically clear themselves when the error no longer exist. However some error codes may required disconnecting power to the system at the unit disconnect switch or circuit breaker in order to clear them and resuming system operations.
  • Page 58 Table 18. 09 through 12 and 30 kBtu System Status and Error Codes — Indoor Character Display and Outdoor LEDs Outdoor LED Displays Indoor (number of blinks) Description System Status Character Display Yellow Green SYSTEM STATUS LEDs Indoor and outdoor System is operating normally.
  • Page 59 Continued — 09 through 12 and 30 kBtu System Status and Error Codes — Indoor Character Display and Outdoor LEDs Outdoor LED Displays Indoor Troubleshooting for Possible (number of blinks) Error Description System Status Character Causes Display Yellow Green S Check for locked compressor rotor due to excessively high ambient Compressor temperature.
  • Page 60 Continued — 09 through 12 and 30 kBtu System Status and Error Codes — Indoor Character Display and Outdoor LEDs Outdoor LED Displays Indoor Troubleshooting for Possible (number of blinks) Error Description System Status Character Causes Display Yellow Green S Check for proper wiring connec­ tions and loose wires at outdoor Compressor high control (CT1, 2) input plug.
  • Page 61 Continued — 09 through 12 and 30 kBtu System Status and Error Codes — Indoor Character Display and Outdoor LEDs Outdoor LED Displays Indoor Troubleshooting for Possible (number of blinks) Error Description System Status Character Causes Display Yellow Green S Check input voltage on outdoor unit terminal strip (N and L terminals).
  • Page 62 Table 19. 18-24 kBtu System Status and Error Codes — Indoor Character Display and Outdoor LEDs Outdoor Unit LED Status This unit has three display Indoor Troubleshooting for Possible status indicators Error Description System Status Unit Causes ® o OFF Display BLINKS NONE...
  • Page 63 Continued — 18 - 24 kBtu System Status or Error Codes — Indoor Character Display and Outdoor LEDs Outdoor Unit LED Status This unit has three display Indoor Troubleshooting for Possible status indicators Unit Error Description System Status Causes ® o OFF Display BLINKS...
  • Page 64 Continued — 18 - 24 kBtu System Status or Error Codes — Indoor Character Display and Outdoor LEDs Outdoor Unit LED Status This unit has three display Indoor Troubleshooting for Possible status indicators Error Description System Status Unit Causes ® o OFF Display BLINKS...
  • Page 65 Continued — 18 - 24 kBtu System Status or Error Codes — Indoor Character Display and Outdoor LEDs Outdoor Unit LED Status This unit has three display Indoor Troubleshooting for Possible status indicators Unit Error Description System Status Causes ® o OFF Display BLINKS...

  • Page 66: Refrigerant System Flow Diagrams

    Refrigerant System Flow Diagrams The following two diagrams illustrate refrigerant flow in either cooling or heating (heat pump only) operations. TYPICAL AIR CONDITIONER SYSTEM INDOOR UNIT OUTDOOR UNIT 3-WAY MUFFLER SERVICE VALVE Discharge INDOOR COIL ACCUMULATOR Suction COMPRESSOR OUTDOOR COIL STRAINER STRAINER 2-WAY...

  • Page 67: Typical Unit Wiring Diagrams

    Typical Unit Wiring Diagrams The indoor wiring diagram location is on the inside of the cabinet at the terminal connection end. To access the diagram will required removal of the cabinet. The wiring diagram on the outdoor unit is located on the top of the control box. WARNING Electric Shock Hazard.
  • Page 68 TYPICAL INDOOR UNIT WIRING DIAGRAM — 24 KBTU SYSTEMS (208 / 230V) RECEIVER AND ROOM TUBE DISPLAY BOARD TEMP. SENSOR TEMP. SENSOR TERMINAL MAGNETIC BLOCK RING N(1) ROOM TUBE DISP1 DISP2 COM−OUT AC−L AP2: MAIN BOARD JUMP YEGN(GN) C0NNECTING SWING−UD2 DC−MOTOR CABLE YEGN(GN)
  • Page 69 TYPICAL OUTDOOR UNIT WIRING DIAGRAM — 09 AND 12 KBTU SYSTEMS (208 / 230V) HEAT PUMP COMP TUBE OUTROOM EXHAUST CT1,2 COMP TEM.SENSOR TEM.SENSOR TEM.SENSOR W8 YEGN W4 YEGN W10 RD W6 YE W7 RD W5 BU W13 WH COMP−U COMP−V COMP−W OVC−COMP W2 BU N(1)
  • Page 70 TYPICAL OUTDOOR UNIT WIRING DIAGRAM — 18 KBTU SYSTEMS (208 / 230V) HEAT PUMP WARNING OVERLOAD PROTECTOR Please don’t touch any terminal when COMP. the voltage of terminal P(DC+) and YEGN COMP N(DC−) at AP1 is higher than 30V to prevent the risk of electrical shock! MAGNETIC RING...
  • Page 71 TYPICAL OUTDOOR UNIT WIRING DIAGRAM — 24 KBTU SYSTEMS (208 / 230V) HEAT PUMP WARNING OVERLOAD PROTECTOR Please don’t touch any terminal when COMP. the voltage of terminal P(DC+) and YEGN COMP N(DC−) at AP1 is higher than 30V to prevent the risk of electrical shock! MAGNETIC RING...

  • Page 72: Troubleshooting

    Troubleshooting SYSTEM FAILED START UP (ALL SIZES) APPLICABLE UNIT SIZE(S): All APPLICABLE ERROR CODE(S): NONE System failed to start. Circuit breaker immediately trips when Measure insulation resistance to set to ON on remote control. ground and see if there is any leakage. Breaker trip or blow fuse.
  • Page 73 Poor system performance. POOR SYSTEM OPERATION (ALL SIZES) Adjust temperature set point. Incorrect temperature setting. Check heating or cooling load calculations. Load demand is greater than system capacity. Repair leak, check refrigerant Low refrigerant due to leak. charge and adjust accordingly. Internal compressor high or low Replace compressor.
  • Page 74 POOR SYSTEM OPERATION (ALL SIZES) (CONTINUED) Indoor fan has malfunction or is damage. Replace indoor fan. Fan motor has a built-in thermal protection identify type of abnormal condition and circuit that may be stopping the motor due correct. to some type of abnormal operation. Indoor fan is not running.
  • Page 75 HEAT PUMP FAILED START UP (CONTINUED) Either outdoor control has malfunction, current limiting circuit protector failed, Replace outdoor control. or relay loop parallel capacitor leakage. Compressor will not start in either Loose or incorrectly installed compressor Verify wiring using unit wiring diagram and heating or cooling harness.
  • Page 76 CAPACITOR CHARGE FAULT (OUTDOOR UNIT) (9-12K BTU SYSTEMS) NOTE— Reactor (choke) line test procedure reference here is applicable for both the APPLICABLE ERROR CODE(S): PU, PH 115V and 208-230V systems. VERIFY VOLTAGE 115VAC Systems: Use AC voltmeter to check voltage between L and Switch unit on and wait one N on outdoor control.
  • Page 77 OUTDOOR UNIT HIGH TEMPERATURE AND OVERLOAD PROTECTION High temperature and overload protection APPLICABLE UNIT SIZE(S): All APPLICABLE ERROR CODE(S): E1, E5, H4 Is the outdoor ambient This is a normal protection temperature higher than feature of the unit. once 127ºF (53ºC)? outdoor ambient air temperature drops below 53ºC (127ºF) system will operate.
  • Page 78 OUTDOOR UNIT OVERLOAD AND DISCHARGE LINE SENSOR MALFUNCTION APPLICABLE UNIT SIZE(S): All APPLICABLE ERROR CODE(S): E4, H4 Is the electronic expansion valve terminal Is wired FA connected correctly. correctly? Resistances between the blue wire terminal and all other wire terminals should be within +5 of each other.
  • Page 79 OUTDOOR POWER FACTOR CORRECTION FAULT APPLICABLE UNIT SIZE(S): All APPLICABLE ERROR CODE(S): HC Start Check the outdoor wiring connections for both the reactor (choke) line and power factor correction capacitor Any damage or Replace damage Is fault corrected? short circuit? component Remove power factor correction capacitor...
  • Page 80 INTER-UNIT COMMUNICATION ERROR Start APPLICABLE UNIT SIZE(S): All APPLICABLE ERROR CODE(S): E6 Did the system operate normally before the failure Verify inter-unit wiring using occurred? the unit wiring diagram See page 87 for procedure for testing communication line. Check inter-unit Is connection wiring correct?

  • Page 81: Major System Components

    Major System Components This section describes the following system components. 1. COMPONENT: INDOOR FAN MOTOR DESCRIPTION: The indoor fan is driven by a single-phase (115V) AC motor. The motor adopts step-less speed regulation to operate at different speeds. The motor speeds are determined by the output voltage and frequency signal from the indoor control.
  • Page 82 3. COMPONENT: OUTDOOR FAN MOTOR ELECTRICAL CHARACTERISTICS: Power supply: 100~120V Frequency: 60Hz Number of poles: 2 or 4 Output power: 90W. Description: Single-phase capacitor run asynchronous DC motor with iron shell. This type of motor is reliable, highly efficient, well structure, low noise output with minimum vibration attributes.
  • Page 83 5. COMPONENT: ROTARY COMPRESSOR WITH ACCUMULATOR (CONTINUED) RESISTANCE BETWEEN EACH SET OF WINDINGS SHOULD BE EQUAL. TROUBLESHOOTING (CONTINUED): Check winding resistance of each terminal. If resistance value is 0 ohms or infinite, replace compressor. 6. COMPONENT: COMPRESSOR TEMPERATURE OVERLOAD PROTECTION DESCRIPTION: If temperature detected by the overload sensor exceeds 239ºF (115ºC), the compressor will stop and the outdoor fan...
  • Page 84 8. COMPONENT: ELECTRONIC EXPANSION VALVE DESCRIPTION: Electronic expansion valve is used in Inverter air conditioning system adjust flow refrigerant automatically. Thus the air conditioner can always stay at the optimized working conditions with quick cooling, precise temperature control, low energy consumption, etc. This valve is reversible and can control the flow under either cooling or heating condition.
  • Page 85 10. COMPONENT: REVERSING VALVE (HEAT PUMP ONLY) DESCRIPTION: The 4-way reversing valve is a component that switches the system between cooling and heating modes. By switching the flow of refrigerant, the heat pump can incorporate the functions of cooling in summer and heating in winter together.
  • Page 86 12. COMPONENT: STRAINERS DESCRIPTION: Mesh strainers are required on the inlet and outlet of the electronic expansion valve to prevent debris from entering the valve. TROUBLESHOOTING: Normally strainers should not have any temperature differences between the inlet and outlet as shown in item 1 below.
  • Page 87 15. COMPONENT: INDOOR TRANSFORMER DESCRIPTION: Indoor unit contains a transformer that will convert the 115 power to 12VAC or on some units there are two output voltages. The transformer in the pictured shows a transformer that will output 12VAC (yellow wires) and 8.5VAC (white wires).

  • Page 88: Optional Condensate Pump Wiring Connection

    Optional Condensate Pump Wiring Connection In order to use one of the condensate pumps available from Lennox, the pump will need to be wired as illustrated in the following diagram. Mini Orange INCOMING 115V POWER WIRES BLACK LINE 1 PERMANENTLY...
  • Page 89 3. Loosen the clasps that secure the louvers to the case 5. Lift the screw cover to access the screws that secure cover. Bend the louver slightly to remove it. the lower portion of the front cover to the unit. 4.
  • Page 90 7. Remove the screws that secure the upper portion of the front cover to the unit. 6. Remove the two screws that secure the display to the front panel. 8. Remove the access cover. Page 90 MS8C / MS8H (208-230V)
  • Page 91 OUTDOOR UNIT DIS-ASSEMBLY Step Outdoor Unit Procedure 1. Remove the top cover and front-side plates. Remove the screws that secure the top panel to unit. TOP PANEL Remove top panel. Remove the screws that secure the valve cover to VALVE the unit.
  • Page 92 3. Remove panel Remove the screws securing the coil guard to the COIL GUARD chassis. Remove coil guard. 4. Remove handle Remove the screws securing the handle to chassis. Remove handle. handle HANDLE 5. Remove right-side panel. Remove screws securing the right-side panel to RIGHT-SIDE PLATE the chassis, valve support and condenser.
  • Page 93 6. Remove electric box Remove screws securing electric box cover. Remove cover. ELECTRIC BOX COVER Remove screws securing the electric box. Pull out the wiring terminal by cutting the tie straps. ELECTRIC BOX Pull electric box upwards to remove. Remove screws securing the electric box 2 to the ELECTRIC BOX 2 left-side plate.
  • Page 94 7. Remove left-side plate Remove screws securing the left-side plate with LEFT-SIDE PLATE the chassis. Remove left-side plate. CHASSIS 8. Remove axial flow blade Remove the nut that secure the fan blade to the fan motor shaft. Remove fan blade. FAN BLADE 9.
  • Page 95 Remove screws that secure the fan motor support to the chassis. To remove, pull assembly upwards. FAN MOTOR SUPPORT CHASSIS 10. Remove Reversing Valve De-braze the piping between the following components: REVERSING VALVE Compressor OUTDOOR COIL Outdoor coil Valves Remove reversing valve. VALVES Page 95 Corp.
  • Page 96 11. Remove 2-Way Shutoff and 3-Way Service Valves Remove bolts securing the valve assembly. De-braze joint between 3-way service valve and air-return pipe and remove valve. 3-WAY VALVE De-braze solder joint between 2-way shut-off valve and connection pipe of valve and remove valve.
  • Page 97 14. Remove Coil Support Plate. Remove screws securing the support plate to the coil. Remove support plate. COIL SUPPORT PLATE 15. Remove Chassis and Coil Pull coil upwards to separate from the chassis. COIL CHASSIS Page 97 Corp. 1244-L9...

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