Lennox XC21 Installation Instructions Manual
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Lennox XC21 Installation Instructions Manual

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See also: Instruction and Installation Manual , Engineering Data
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E2010 Lennox Industries Inc.
Dallas, Texas, USA
NOTICE
A thermostat is not included and must be ordered
separately.
D The Lennox icomfort Touch™ thermostat must be used
in communicating applications.
D In non−communicating applications,
®
ComfortSense
7000 thermostat may be used, as well
as other non−communicating thermostats.
In all cases, setup is critical to ensure proper system
operation.
Field
wiring
examples
applications begin on page 23.
See the icomfort Toucht thermostat Quick Start Guide
for communicating and partial communicating field
wiring connections.
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.

General

This outdoor unit is designed for use with HFC−410A
refrigerant only. This unit must be installed with an
approved indoor air handler or coil. See the Lennox XC21
Engineering Handbook for approved indoor component
matchups.
IMPORTANT
This model is designed for use in expansion valve
systems only. An indoor expansion valve approved for
use with
HFC−410A
separately, and installed prior to operating the system.
06/10
*2P0610*
the Lennox
for
non−communicating
refrigerant must be ordered
INSTALLATION
INSTRUCTIONS
Dave Lennox Signature
Collection XC21 System
AIR CONDITIONER
506518−01
06/10
Supersedes 05/10
RETAIN THESE INSTRUCTIONS
FOR FUTURE REFERENCE

TABLE OF CONTENTS

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Shipping and Packing List

Check unit for shipping damage. Consult last carrier
immediately if damage is found.
1
Assembled outdoor unit.
1
Bag assembly which includes the following:
1
Bushing (for low voltage wiring)
2
Isolation grommets for liquid and suction lines
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*P506518-01*
®
Litho U.S.A.
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Summary of Contents for Lennox XC21

  • Page 1: Table Of Contents

    ........refrigerant only. This unit must be installed with an approved indoor air handler or coil. See the Lennox XC21 Shipping and Packing List Engineering Handbook for approved indoor component matchups.

  • Page 2: Unit Dimensions

    Unit Dimensions − Inches (mm) and Parts Arrangement DISCHARGE 39−1/2 35−1/2 ELECTRICAL (1003) (902) INLETS (1194) SUCTION LINE INLET 4−1/2 (114) LIQUID LINE INLET 18−1/2 (470) 8 (203) SIDE VIEW 1 (25) ACCESS VIEW UNIT SUPPORT FEET 26−7/8 (683) 16−7/8 (429) 8−3/4 (222)

  • Page 3: Typical Unit Parts Arrangement

    VALVE PORT LIQUID LINE SERVICE VALVE PORT FIELD CONNECTION FOR LIQUID LINE LIQUID LINE FILTER DRIER (SINGLE FLOW) S4 HIGH PRESSURE SWITCH S87 LOW PRESSURE SWITCH S40 CRANKCASE THERMOSTAT Figure 1. Plumbing, Switches and Sensor Components Page 3 XC21 SERIES...

  • Page 4: Operating Gauge Set And Service Valves

    Lennox Industries Inc. recess. P.O. Box 799900 See the Lennox Service and Application Notes #C−08−1 Dallas, TX 75379−9900 for further details and information. IMPORTANT IMPORTANT This unit must be matched with an indoor coil as To prevent stripping of the various caps used, the specified in Lennox’...

  • Page 5: Service Valves

    Without Torque Wrench: Finger tighten and use an appropriately sized wrench to turn an additional 1/12 turn clockwise. NOTE A label with specific torque requirements may be affixed to the stem cap. If the label is present, use the specified torque. Figure 2. Angle and Ball Service Valves Page 5 XC21 SERIES...

  • Page 6: Recovering Refrigerant From Existing System

    Recovering Refrigerant from Existing System RECOVERING REFRIGERANT FROM SYSTEM DISCONNECT POWER CONNECT MANIFOLD GAUGE SET Disconnect all power to the existing outdoor unit at the disconnect Connect a gauge set, clean recovery cylinder and a recovery switch or main fuse box/breaker panel. machine to the service ports of the existing unit.

  • Page 7: New Outdoor Unit Placement

    If it is necessary to extend to a window see the provided illustration in figure 5, further, consider a different type of field−fabricated detail A. framework that is sturdy enough for greater heights. Page 7 XC21 SERIES...
  • Page 8 STABILIZING UNIT ON UNEVEN SURFACES ROOF MOUNTING IMPORTANT Install the unit a minimum of 6 inches (152 mm) above the roof surface to avoid ice build−up around the unit. Locate the unit above a load bearing wall or area of the roof that Unit Stabilizer Bracket Use (field−provided): can adequately support the unit.
  • Page 9 To help stabilize an outdoor unit, some installations may require strapping the unit to the pad using brackets and anchors commonly available in Elevated Slab Mounting using Feet the marketplace. Extenders Figure 5. Placement, Slab Mounting and Stabilizing Unit Page 9 XC21 SERIES...

  • Page 10: Removing And Installing Panels

    Removing and Installing Panels ACCESS PANEL REMOVAL PANELS Removal and reinstallation of the access panel is as illustrated. ACCESS AND LOUVERED REMOVE 4 SCREWS TO REMOVE PANEL FOR WARNING ACCESSING COMPRESSOR To prevent personal injury, or damage to panels, unit or structure, be sure to observe AND CONTROLS.

  • Page 11: New Or Replacement Line Set

    Model (XC21) and size of unit (e.g. −036). New or Replacement Line Set REFRIGERANT LINE SET Line set diameters for the unit being installed as listed in table 2 and total length of installation. This section provides information on installation or replacement of existing line set.
  • Page 12 LINE SET IMPORTANT Refrigerant lines must not contact structure. INSTALLATION REFRIGERANT LINE SET INSTALLING Line Set Isolation The following illustrations are VERTICAL RUNS (NEW CONSTRUCTION SHOWN) examples of proper refrigerant line set isolation: NOTE Insulate liquid line when it is routed through areas where the surrounding ambient temperature could become higher than the REFRIGERANT LINE SET TRANSITION...
  • Page 13 SERVICE PORT CAP CAN DAMAGE VALVE SEALS SERVICE PORT IMPORTANT Connect gauge set low pressure side to vapor line service valve and repeat procedure starting at paragraph 4 for brazing the liquid line to service port valve. Page 13 XC21 SERIES...

  • Page 14: Flushing The System

    Flushing the System TYPICAL CHECK EXPANSION VALVE FLUSHING REMOVAL PROCEDURE (Uncased Coil Shown) STUB END LINE SET AND INDOOR COIL (1 OF 2) TWO PIECE PATCH PLATE LIQUID LINE CHECK (UNCASED COIL ONLY) ORIFICE EXPANSION TYPICAL FIXED ORIFICE REMOVAL PROCEDURE HOUSING VALVE DISTRIBUTOR...
  • Page 15 FLUSHING LINE SET AND INDOOR COIL (2 OF 2) TYPICAL CHECK EXPANSION VALVE INSTALLATION PROCEDURE This outdoor unit is designed for use in systems that use check expansion valve metering device. See the Lennox XC21 Engineering Handbook for approved check expansion valve kit match−ups and application information.

  • Page 16: Leak Testing The System

    Polyol ester (POE) oils death. are used in Lennox units charged with HFC−410A refrigerant. Residual mineral oil can act as an Never use oxygen to pressurize or insulator, preventing proper heat transfer. It can also purge refrigeration lines.
  • Page 17 After a few minutes, open one of the service valve ports and verify that the refrigerant added to the system earlier is measurable with a leak detector. After leak testing disconnect gauges from service ports. Page 17 XC21 SERIES...

  • Page 18: Evacuating The System

    Evacuating the System EVACUATING MANIFOLD GAUGE SET LINE SET AND INDOOR COIL CONNECT GAUGE SET HIGH NOTE Remove cores from service valves (if not al- ready done). Connect low side of manifold gauge set with 1/4 SAE in−line tee to vapor line service valve A34000 1/4 SAE TEE WITH Connect high side of manifold gauge...

  • Page 19: Electrical

    (ESD) putting the unit, the control and the technician at the same electrostatic potential. Precautions and Procedures Neutralize electrostatic charge by touching hand and all tools on an unpainted unit surface before performing any service procedure. Page 19 XC21 SERIES...
  • Page 20 ROUTE CONTROL WIRES NON−COMMUNICATING Install low voltage control wiring from outdoor to indoor unit and from thermostat to indoor unit as illustrated. CONTROL BOX Run 24VAC control wires through hole with grommet. Make 24VAC control wire connections to A175 main control. NOTE Do not bundle any excess 24VAC control wires inside control box.
  • Page 21 Figure 8. Typical XC21 Wiring Page 21 XC21 SERIES...

  • Page 22: A175 Main Control Jumpers And Terminals

    A175 Main Control Jumpers and Terminals Table 3. A175 Main Control Jumpers and Terminals A175 MAIN CONTROL − TWO−STAGE Board ID Label Description PSC Fan 240 VAC output connection for outdoor fan. Table 3 provides additional information concerning PSC Fan 240 VAC input connection for outdoor fan.

  • Page 23: Field Control Wiring

    Toucht thermostat Quick Start Guide which is provided with the thermostat. Air Handler ComfortSense[ 7000 Thermostats Catalog # Y0349 or Y2081 XC21 Two−Stage Air Conditioner A175 Control On−board link Low voltage thermostat wiring Flat metal jumper Outdoor sensor for outdoor temperature display (Optional).
  • Page 24 Furnace ComfortSense[ 7000 Thermostats Catalog # Y0349 or Y2081 XC21 Two−Stage Air Conditioner A175 Control On−board link Low voltage thermostat wiring Outdoor sensor for outdoor temperature display (Optional). R connection required for outdoor unit with Air Conditioner A175 Control LSOM function. Resistor Kit (Cat# 47W97) is required when using the ComfortSense 7000 (Y0349) with Air Conditioner A175 Control LSOM feature.

  • Page 25: Servicing Units Delivered Void Of Charge

    Position temperature sensor on liquid line DIGITAL SCALE near liquid line service port. TEMPERATURE SENSOR (LIQUID LINE) TO LIQUID LINE SERVICE VALVE TEMPERATURE SENSOR Figure 11. Gauge Set Setup and Connections Page 25 XC21 SERIES...
  • Page 26 ADDING OR REMOVING REFRIGERANT This system uses HFC−410A refrigerant which operates at much higher pressures than HCFC−22. The pre−installed liquid line filter drier is approved for use with HFC−410A only. Do not replace it with components designed for use with HCFC−22. This unit is NOT approved for use with coils which use capillary tubes or fixed orifices as a refrigerant metering device.
  • Page 27 20 psig. NOTE The exampled nameplate is for illustration purposes only. Use data listed on actual unit nameplate for charging. Figure 14. Using HFC−410A Weigh In Method Page 27 XC21 SERIES...
  • Page 28 APPROACH 1. Confirm proper airflow across coil using figure 12. 2. Compare unit pressures with table 4, Normal Operating Pressures. TEST AND CHARGE METHOD 3. Use APPROACH to correctly charge unit or to verify the charge is 65ºF (18.3ºC) and Above correct.

  • Page 29: Operating And Temperature Pressures

    29.4 −10 −23.3 36.8 32.2 −5 −20.6 42.5 35.0 −17.8 48.6 37.8 −15.0 55.2 40.6 −12.2 62.3 43.3 −9.4 70.0 46.1 −6.7 78.3 48.9 −3.9 87.3 51.7 −1.1 96.8 54.4 57.2 60.0 62.8 10.0 65.6 12.8 Page 29 XC21 SERIES...

  • Page 30: System Operations

    COIL TEMPERATURE SENSOR System Operation This model does not use a coil temperature sensor. The cable assembly attached to the A175 main control’s E30 IMPORTANT connection has a 10K resister installed between pins 5 and 6 as illustrated in figure 17. Some scroll compressor have internal vacuum protector If the resistor is damage or missing, a Coil Sensor Problem that will unload scrolls when suction pressure goes...
  • Page 31 If the jumper remains on the E33 pins for longer than five seconds, the A175 Main Control will ignore the JUMPER ON E33 pins and revert to normal operation. Figure 18. Multi−Function E33 Jumper (Test) Pin Page 31 XC21 SERIES...
  • Page 32 Table 7. Ambient Sensor Temperature / Resistance Range Degrees Degrees Degrees Degrees Resistance Resistance Resistance Resistance Fahrenheit Fahrenheit Fahrenheit Fahrenheit 136.3 2680 56.8 16657 21.6 44154 −11.3 123152 133.1 2859 56.0 16973 21.0 44851 −11.9 125787 130.1 3040 55.3 17293 20.5 45560 −12.6...
  • Page 33 142.3 2380 100.1 5814 193.1 141.5 2418 99.3 5920 191.9 140.7 2456 98.5 6028 190.7 139.9 2495 97.7 6139 189.5 139.1 2534 96.9 6253 188.4 1011 138.3 2574 96.1 6370 187.2 1031 137.6 2615 95.3 6489 Page 33 XC21 SERIES...

  • Page 34: A175 Main Control Led System Status

    RESETTING LED ALERT CODES A175 Main Control LED System Status LED alert codes can be reset manually or automatically: and Alert and Codes 1. Manual Reset LED alert codes are display using various LEDs located on Manual reset can be achieve by one of the following the A175 Main Control.
  • Page 35 System stored configuration data is corrupted. System will not run. Refer to NONE NONE Code 131 Parameters communicating thermostat for memory corrupt handling. Critical Alert Failed Flash CRC No operations, A175 control enters boot loader mode. Alarm will clears after NONE NONE Code 132 check. reset. Page 35 XC21 SERIES...
  • Page 36 Outdoor A175 Main icomfort icomfort icomfort Control LEDs Toucht Toucht Toucht Possible Possible Possible Condition Condition Condition Solution Solution Solution Cause(s) Cause(s) Cause(s) Thermostat Thermostat Thermostat DS11 DS11 DS14 Red DS14 Red Display Display Display Green Green Restricted air SLOW Moderate Alert Low Pressure flow over indoor...
  • Page 37 Pause or after power reset. power to the Condenser fan is not running. compressor. Check fan capacitor Check fan wiring and connectors Check fan motor for failure or block- Return air duct has substantial leakage. Page 37 XC21 SERIES...
  • Page 38 Outdoor A175 Main icomfort icomfort Control LEDs Possible Possible Toucht Toucht Condition Condition Solution Solution Clearing Status Clearing Status Cause(s) Cause(s) Thermostat Thermostat DS15 DS13 Display Display Yellow Thermostat demand signal is intermittent. Clears after four 3 Flashes Moderate Compressor is Time delay relay or A175 Main Control is consecutive normal then...
  • Page 39 Figure 19. High Pressure Switch Operation Page 39 XC21 SERIES...
  • Page 40 Figure 20. Low Pressure Switch Operation Page 40 506518−01...
  • Page 41 Figure 21. High Discharge Temperature Sensor Operation Page 41 XC21 SERIES...

  • Page 42: Maintenance (Dealer And Homeowner)

    8. When the required LED capacity code (see table 1) Maintenance has displayed on the A175 main control, remove the jumper from FIELD TEST pins while the code is still displaying. WARNING 9. The A175 main control will continue to display the unit nominal capacity code until 24 volts is removed from Electric shock hazard.
  • Page 43 Code Code Code XC21−024 15.1 17.6 XC−036 16.8 19.2 XC21−048 and 19.2 21.6 XC21−060 * LED Code indicates A177 Fan Motor Control LED flash sequence. For example, LED Code 9 indicates 9 slow flashes and pause. Page 43 XC21 SERIES...
  • Page 44 FAN MOTOR PWM CONTROL (TWO STAGE AND VARIABLE SPEED FAN DEMAND BEGINS DEFAULT MISMATCHED REPLACE FAN MOTOR FAN MOTOR CONTROL BOARD LED CONTINUOUS FAST SPEED USED FLASH DEFAULT FAN REPLACE FAN MOTOR MOTOR FAILURE LED CONSTANT ON CONTROL BOARD SPEED USED FAN MOTOR LED STAGE INDICATOR: ONE STAGE...
  • Page 45 S4 HIGH PRESSURE SWITCH YELLOW BLUE BLACK YELLOW YELLOW A177 FAN YELLOW YELLOW MOTOR SEE TABLE 16 FOR CFM PROFILE CONTROL SELECTION OPTIONS. A175 MAIN CONTROL Figure 24. A177 Fan Control, Wiring, Jumper Settings, Testing and LED Location Page 45 XC21 SERIES...
  • Page 46 CONTROL PANEL A177 FAN MOTOR CONTROL PULSE−WIDTH MODULATION (PWM) INPUT VOLTAGES DURING DEMAND ECM/Y1 ONLY − 24VDC BOTH ECM/Y1 AND ECM/Y2 − 24VDC AT EACH INPUT ECM/Y2 ONLY − 24VDC YELLOW WIRE A175 MAIN BLUE WIRE CONTROL BLACK WIRE ONE YELLOW WIRE FROM PS (E24) TERMINAL ON A175 MAIN CONTROL.
  • Page 47 CONNECT B4 FAN MOTOR WIRE TO 9V BATTERY POSITIVE TERMINAL BLACK LEAD CONNECT B4 FAN MOTOR BLACK COMMON WIRE TO 9V BATTERY NEGATIVE TERMINAL BROWN LEAD NEGATIVE TERMINAL POSITIVE TERMINAL FULLY CHARGED 9V BATTERY Figure 26. B4 Fan Motor Test Page 47 XC21 SERIES...
  • Page 48 INDOOR UNIT MAINTENANCE Indoor Unit 1. Clean or change filters. 2. Lennox blower motors prelubricated permanently sealed. No more lubrication is needed. 3. Adjust blower speed for cooling. Measure the pressure drop over the coil to determine the correct blower CFM.
  • Page 49 NOTE If you are unsure about the filter required for your system, call your Lennox dealer for assistance. CAUTION 3. Reusable Filter Many indoor units are equipped with reusable foam filters. Clean foam filters with a...

  • Page 50: Checklists

    Checklists Two−Stage Modulation Compressors Field Operational Checklist Expected results during Y2 Unit Readings Y1 − First Stage demand (Toggle switch On) Y2 − Second Stage COMPRESSOR Voltage Same Amperage Higher CONDENSER FAN MOTOR Amperage Same or Higher TEMPERATURE Ambient Same Outdoor Coil Discharge Air Higher Compressor Discharge Line...
  • Page 51 XC21 Start−Up and Performance Checklist Customer Address Indoor Unit Model Serial Outdoor Unit Model Serial Notes: START UP CHECKS Refrigerant Type: First Stage: Rated Load Amps Actual Amps Rated Volts Actual Volts Second Stage: Rated Load Amps Actual Amps Rated Volts...

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