Lennox XC20-036-230-01, XC20-060-230-01, XC20-024-230-01, XC20-048-230-01 Installation And Service Procedure

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Page 1

INSTALLATION AND SERVICE

PROCEDURE

Service Literature

Elite Series

Corp. 1407-L10

August 25, 2015

IMPORTANT

XC20 units have refrigerant piping requirements that are unique to this unit. Size and install the refrigerant piping per table 2 (page 14) to ensure proper unit operation.

IMPORTANT:

Before applying any power (main or low voltage) to the outdoor unit, confirm that the iComfort Wi-Fi® or iComfort® S30 thermostat has software Version 2.1 or higher installed. (Reference the iComfort Wi-Fi® or iComfort® S30 thermostat manual.)

This unit is an integral component of a system that requires an iComfort Wi-Fi iComfort

XC20

or iComfort® S30 thermostat and

-enabled air handler or furnace.

iComfort Wi-Fi

thermostat

iComfort

thermostat

S30

iComfort

air handler or

furnace

-enabled

XC20

XC20 Units

TABLE OF CONTENTS

I. OVERVIEW

Model Number Identification 2....................

Typical Serial Number Identification 2..............

Specifications 2.................................

Electrical Data 3................................

Unit Dimensions 4..............................

Typical Unit Parts Arrangement 5.................

Operating Service Valves 7.......................

General 7.....................................

II. INSTALLATION

Unit Placement 9...............................

Removing and Installing Panels 12.................

New or Replacement Line Set 13..................

Brazing Connections 16...........................

Flushing the System 19...........................

Leak Testing the System 21.......................

Evacuating the System 21.........................

Electrical 24.....................................

Servicing Unit Delivered Void of Charge 29..........

Unit Start-Up 29.................................

III. SYSTEM OPERATION AND SERVICE

7-Segment Alert and System Status Codes 30.......

Outdoor Control Push-Button Operation 38..........

Configuring Unit 42...............................

Reconfiguring Outdoor Control using iComfort Wi-Fi iComfort

System Overview 43.............................

Maintenance 44..................................

Unit Wiring Diagrams 45..........................

Factory Wiring Diagrams 48.......................

Unit Sequence of Operations 50...................

Component Testing 53............................

System Refrigerant 75............................

Appendix - Charging Sticker ....................

S30 Thermostat 43.....................

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.

2015 Lennox Industries Inc.

Page 2

Model Number Identification

I. OVERVIEW

Refrigerant Type

X = R-410A

Unit Type

C = AIR CONDITIONER

C 20 036

− −

230

Nominal Cooling Capacity

-02

Minor Revision Number

Ratings Revision Level

Voltage

230 = 208/230V-1ph-60hz

024 = 2 tons

Series

036 = 3 tons 048 = 4 tons 060 = 5 tons

Typical Serial Number Identification

Location Code

19 = Saltillo, Mexico

58 = Marshalltown, IA

Year Code

08 = 2008 09 = 2009 10 = 2010

8 09 C

05716

5 (or 6) Digit Unique Number

Month Code

A = January B = February C = March

Specifications

Unit Outdoor Fan

Model Number

XC20-024-230-01 72 65 7 lbs, 5 oz 4 22

Sound Rating Number (dB) Maximum Minimum

Factory Refrigerant

Charge

Number of Blades Diameter - inches.

Unit Outdoor Fan

Model Number

XC20-036-230-01 75 67 8 lbs, 6 oz 4 22

Model Number

XC20-048-230-01 77 68 10 lbs, 7 oz 4 22

Model Number

XC20-060-230-01 77 69 12 lbs, 1 oz 3 26

Tested according to AHRI Standard 270-2008 test conditions.

Factory refrigerant charge is sufficient for refrigerant line lengths up to 15 feet.

Sound Rating Number (dB) Maximum Minimum

Unit Outdoor Fan

Factory Refrigerant

Charge

Number of Blades Diameter - inches.

XC20

Page 3

Electrical Data

208/230V-60 Hz-1 Ph

Unit Compressor Outdoor Fan (RPM varies with compressor RPM)

Model Number

Maximum

Over-

current

Protection

(amps)

Minimum

Circuity

Ampacity

XC20-024-230-01 30 19.1 13.0 13.0 1/6 2600 1500 700 400 60 25 2.8

Unit Compressor Outdoor Fan (RPM varies with compressor RPM)

Model Number

Maximum

Over-

current

Protection

(amps)

Minimum

Circuity

Ampacity

XC20-036-230-01 30 20.6 14.2 13.0 1/4 3600 3100 700 600 115 80 2.8

Unit Compressor Outdoor Fan (RPM varies with compressor RPM)

Model Number

Maximum

Over-

current

Protection

(amps)

Minimum

Circuity

Ampacity

XC20-048-230-01 50 29.1 21.0 20.0 1/3 4000 3000 800 600 160 70 2.8

Unit Compressor Outdoor Fan (RPM varies with compressor RPM)

Model Number

Maximum

Over-

current

Protection

(amps)

Minimum

Circuity

Ampacity

XC20-060-230-01 50 29.3 21.2 20.0 1/3 4325 2900 865 600 195 80 2.8

HACR type circuit breaker or fuse.

Refer to National or Canadian Electrical Code manual to determine wire, fuse and disconnect size requirements.

Rated

Load

Amps

(RLA)

Locked

Rotor Amps (LRA)

Motor

CFM RPM WATTS

MAX MIN MAX MIN MAX MIN

Load Amps (FLA)

208/230V-60 Hz-1 Ph

Rated

Load

Amps

(RLA)

Locked

Rotor Amps (LRA)

Motor

CFM RPM WATTS

MAX MIN MAX MIN MAX MIN

Load Amps (FLA)

208/230V-60 Hz-1 Ph

Rated

Load

Amps

(RLA)

Locked

Rotor Amps (LRA)

Motor

CFM RPM WATTS

MAX MIN MAX MIN MAX MIN

Load Amps (FLA)

208/230V-60 Hz-1 Ph

Rated

Load

Amps

(RLA)

Locked

Rotor Amps (LRA)

Motor

CFM RPM WATTS

MAX MIN MAX MIN MAX MIN

Load Amps (FLA)

Full

XC20

Page 4

Unit Dimensions -- Inches (mm)

35−1/2 (902)

2 (51)

39−3/8 (1000)

DISCHARGE AIR

LIQUID LINE CONNECTION

ELECTRICAL INLETS

SUCTION LINE CONNECTION

4−1/4(108)

4−3/4 (121)

SIDE VIEW

1 (25)

Model No.

XC20−024 39 991

XC20−036 39 991

XC20−048 45 1143

XC20−060 45 1143

END VIEW

in. mm

UNIT SUPPORT FEET

16−7/8

(429)

8−3/4 (222)

3−1/8

(79)

26−7/8

(683)

)3−3/4 (95

30−3/4 (781)

4−5/8 (117)

IMPORTANT

This unit must be matched with an indoor coil as specified in Lennox Product Specification bulletin. Coils previously charged with HCFC-22 must be flushed.

CAUTION

As with any mechanical equipment, contact with sharp sheet metal edges can result in personal injury. Take care while handling this equipment and use protective clothing.

BASE WITH ELONGATED LEGS

WARNING

Electric Shock Hazard. Can cause injury or death. Unit must be grounded in accordance with national and local codes. Line voltage is present at all components when unit is not in operation on units with single‐pole contactors. Disconnect all remote electric power supplies before opening access panel. Unit may have multiple power supplies.

WARNING

Electrical Hazard

High Voltage

Wait 5 Minutes

Electrical components may hold charge. Do not remove this panel or service this area for 5 minutes after the power has been removed.

XC20

Page 5

Typical Unit Parts Arrangement

OUTDOOR

CONTROL

INVERTER REACTOR

CONTROL PANEL FOR

XC20-024 AND -036

DC INVERTER

CONTROL

GROUND LUG

CONTACTOR-SPST

OUTDOOR CONTROL

INVERTER REACTOR

CONTROL PANEL FOR

XC20-048 AND -060

DC INVERTER CONTROL

INVERTER NOISE FILTER

GROUND LUG

CONTACTOR-SPST

Figure 1. Control Panel Components

XC20

Page 6

COMPRESSOR TOP CAP

SWITCH (THERMAL)

Typical Plumbing Components

COMPRESSOR

CRANKCASE HEATER THERMOSTAT (S40) OPENS AT 70ºF, CLOSES AT 50ºF

(ONE WAY - HFC-410A)

DRIER

LIQUID LINE SENSOR

SERVICE VALVE

Figure 2. Plumbing Component Locations

IMPORTANT

This unit must be matched with an indoor coil as specified in Lennox Product Specification bulletin. Coils previously charged with HCFC-22 must be flushed.

LOW PRESSURE

SWITCH

HIGH PRESSURE

SERVICE VALVE

SWITCH

CAUTION

As with any mechanical equipment, contact with sharp sheet metal edges can result in personal injury. Take care while handling this equipment and use protective clothing.

XC20

Page 7

WARNING

Electric Shock Hazard. Can cause injury or death. Unit must be grounded in accordance with national and local codes.

Line voltage is present at all components when unit is not in operation on units with single‐pole contactors. Disconnect all remote electric power supplies before opening access panel. Unit may have multiple power supplies.

General

These instructions are intended as a general guide and do not supersede local codes in any way. Consult authorities who have jurisdiction before installation.

The XC20 is a high-efficiency residential split-system air conditioner, which features a variable-capacity scroll com pressor and uses HFC-410A refrigerant. Units are available in 2, 3, 4 and 5-ton sizes. The series is designed for use with an expansion valve (approved for use with HFC-410A) in the indoor unit only.

USING MANIFOLD GAUGE SET

When checking the system charge, only use a manifold gauge set that features low loss anti-blow back fittings.

Manifold gauge set used with HFC-410A refrigerant sys tems must be capable of handling higher system operating pressures. The gauges should be rated for use with pres sures of 0 - 800 psig on the high side and a low side of 30” vacuum to 250 psig, with dampened speed to 500 psi. Gauge hoses must be rated for use at or up to 800 psig of pressure with a 4000 psig burst rating.

Table 1. Torque Requirements

Parts Recommended Torque

Service valve cap 8 ft.- lb. 11 NM

Sheet metal screws 16 in.- lb. 2 NM

Machine screws #10 28 in.- lb. 3 NM

Compressor bolts 90 in.- lb. 10 NM

Gauge port seal cap 8 ft.- lb. 11 NM

TORQUE REQUIREMENTS

When servicing or repairing HVAC components, ensure the fasteners are appropriately tightened. Table 1 lists torque values for fasteners.

Operating Service Valves

The liquid and vapor line service valves are used for re moving refrigerant, flushing, leak testing, evacuating, checking charge and charging.

Each valve is equipped with a service port which has a fac tory-installed valve stem. Figure 3 provides information on how to access and operating both angle and ball service valves.

IMPORTANT

Only use hex wrenches of sufficient hardness (50Rc Rockwell Harness Scale minimum). Fully insert the wrench into the valve stem recess.

Service valve stems are factory-torqued (from 9 ft-lbs for small valves, to 25 ft-lbs for large valves) to prevent refrigerant loss during shipping and handling. Using a hex 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 Note #C-08-1 for further details and information.

WARNING

The State of California has determined that this product may contain or produce a chemical or chemicals, in very low doses, which may cause serious illness or death. It may also cause cancer, birth defects, or reproductive harm.

IMPORTANT

To prevent stripping of the various caps used, the appropriately sized wrench should be used and fitted snugly over the cap before tightening.

XC20

Page 8

SERVICE VALVES

ANGLE AND BALL

Operating Angle–Type Service Valve:

1. Remove stem cap with an appropriately sized wrench.

2. Use a service wrench with a hex-head extension (3/16” for liquid line valve sizes and 5/16” for vapor line valve sizes) to back the stem out counterclockwise as far as it will go.

SERVICE PORT CAP

SERVICE PORT CORE

(VALVE STEM SHOWN CLOSED) INSERT HEX WRENCH HERE

TO INDOOR

UNIT

(VALVE STEM SHOWN OPEN) INSERT HEX WRENCH HERE

STEM CAP

TO OUTDOOR UNIT

ANGLE-TYPE SERVICE VALVE

(BACK-SEATED OPENED)

When service valve is OPEN, the service port is open to line set, indoor and outdoor unit.

Operating Ball Type Service Valve:

1. Remove stem cap with an appropriately sized wrench.

2. Use an appropriately sized wrenched to open. To open valve, rotate stem counterclockwise 90°. To close, rotate stem clockwise 90°.

TO INDOOR UNIT

TO OPEN ROTATE STEM COUNTERCLOCKWISE 90°.

TO CLOSE ROTATE STEM CLOCKWISE 90°.

SERVICE PORT

CORE

CAP

TO OUTDOOR

UNIT

BALL (SHOWN CLOSED)

VALV E STEM

STEM CAP

ANGLE-TYPE SERVICE VALVE

(FRONT-SEATED CLOSED)

When service valve is CLOSED, the service port is open to the line set and indoor unit.

To Access Service Port:

A service port cap protects the service port core from contamination and serves as the primary leak seal.

1. Remove service port cap with an appropriately sized wrench.

2. Connect gauge set to service port.

3. When testing is completed, replace service port cap and tighten as follows:

D With torque wrench: Finger tighten and

torque cap per table 1.

D Without torque wrench: Finger tighten and

use an appropriately sized wrench to turn an additional 1/6 turn clockwise.

Reinstall Stem Cap:

Stem cap protects the valve stem from damage and serves as the primary seal. Replace the stem cap and tighten as follows:

D With Torque Wrench: Finger tighten and then

torque cap per table 1.

D Without Torque Wrench: Finger tighten and

use an appropriately sized wrench to turn an additional 1/12 turn clockwise.

1/6 TURN

1/12 TURN

NOTE - A label with specific torque requirements may be affixed to the stem cap. If the label is present, use the specified torque.

Figure 3. Angle and Ball-Type Service Valves

XC20

Page 9

II. INSTALLATION

Unit Placement

CAUTION

This unit may weigh up to 320 lbs. It could take more than two people to lift this product. Take proper precautions when lifting heavy objects.

See Unit Dimensions on page 4 for sizing mounting slab, platforms or supports. Refer to figure 4 for mandatory installation clearance requirements.

POSITIONING CONSIDERATIONS

Consider the following when positioning the unit:

D Some localities are adopting sound ordinances based

on the unit sound level registered from the adjacent property, not from the installation property. Install the unit as far as possible from the property line.

D When possible, do not install the unit directly outside

a window. Glass has a very high level of sound trans mission. For proper placement of unit in relation to a window see figure 5, detail A.

PLACING UNIT ON SLAB

When installing unit at grade level, the top of the slab should be high enough above grade so that water from higher ground will not collect around the unit. The slab should have a slope tolerance as described in figure 5, de tail B.

NOTE - If necessary for stability, anchor unit to slab as de scribed in figure 5, detail D.

ELEVATING THE UNIT

Units are outfitted with elongated support feet as illustrated in figure 5, detail C.

If additional elevation is necessary, raise the unit by ex tending the height of the unit support feet. Use a 2-inch (50.8mm) Schedule 40 female threaded adapter to raise the height of the unit.

The specified coupling will fit snugly into the recessed por tion of the feet. Use additional 2-inch (50.8mm) Schedule 40 male threaded adaptors which can be threaded into the female threaded adaptors to make additional adjustments to the level of the unit.

NOTE - Keep the height of extenders short enough to en sure a sturdy installation. If it is necessary to extend the height further than what is stable, consider a different type of field-fabricated framework that is sturdy enough for greater heights.

NOTES:

Service clearance of 30 in. must be maintained on one of the sides adjacent to the control box.

Clearance to one of the other three sides must be 36 in.

Clearance to one of the remaining two sides may be 12 in. and the final side may be 6 in.

A clearance of 24 in. must be maintained between two units.

48 in. clearance required on top of unit.

See

NOTES

See NOTES

See

NOTES

Control

Box

NOTICE: Specific applications may require adjustment of the listed installation clearances to provide protection for

the unit from physical damage or to avoid conditions which limit operating efficiency. (Example: Clearances may have to be increased to prevent snow or ice from falling on the top of the unit. Additional clearances may also be required to prevent air recirculation when the unit is installed under a deck or in another tight space.)

Figure 4. Installation Clearances

XC20

Page 10

STABILIZING UNIT ON UNEVEN SURFACES

IMPORTANT

Unit Stabilizer Bracket Use (field-provided):

Always use stabilizers when unit is raised above the factory height. (Elevated units could become unstable in gusty wind conditions.)

Stabilizers may be used on factory height units when mounted on unstable an uneven surface.

1. Remove the louvered panel from each side to expose the unit base.

2. Install the brackets as illustrated in figure 5, detail D us ing conventional practices.

3. Replace the panels after installation is complete.

ROOF MOUNTING

Locate the unit above a load-bearing wall or area of the roof that can adequately support the unit. Consult local codes for rooftop applications.

NOTICE

Roof Damage! This system contains both refrigerant and oil. Some

rubber roofing material may absorb oil and cause the rubber to swell when it comes into contact with oil. The rubber will then bubble and could cause leaks. Protect the roof surface to avoid exposure to refrigerant and oil during service and installation. Failure to follow this notice could result in damage to roof surface.

XC20

Page 11

DETAIL A DETAIL B

INSTALL UNIT LEVEL OR, IF ON A SLOPE, MAINTAIN SLOPE TOLERANCE OF 2 DEGREES (OR 2 INCHES PER 5 FEET [50 MM PER 1.5 M]) AWAY FROM BUILDING STRUCTURE.

Install unit away from windows.

TWO 90° ELBOWS INSTALLED IN LINE SET

WILL REDUCE LINE SET VIBRATION.

GROUND LEVEL

Slab Mounting at Ground Level

Outside Unit Placement

BUILDING

STRUCTURE

MOUNTING SLAB

DETAIL C

BASE

LEG DETAIL

2” (50.8MM) SCH 40

FEMALE THREADED

USE ADDITIONAL 2” SCH 40 MALE THREADED ADAPT ERS WHICH CAN BE THREADED INTO THE FEMALE THREADED ADAPTERS TO MAKE ADDITIONAL AD JUSTMENTS TO THE LEVEL OF THE UNIT.

Elevated Slab Mounting using Feet

ADAPTER

2” (50.8MM) SCH 40

MALE THREADED

ADAPTER

Extenders

DETAIL D

Slab Side Mounting

#10 1/2” LONG SELF-DRILLING

SHEET METAL SCREWS

STABILIZING BRACKET (18 GAUGE

METAL — 2” WIDTH; HEIGHT AS

#10 1-1/4” LONG HEX HEAD

SCREW AND FLAT WASHER

CONCRETE SLAB — USE TWO PLASTIC ANCHORS (HOLE DRILL 1/4”)

WOOD OR PLASTIC SLAB — NO PLASTIC ANCHOR (HOLE DRILL 1/8”)

REQUIRED)

CORNER POST

MINIMUM ONE

Deck Top Mounting

STABILIZING BRACKET (18 GAUGE METAL — 2” (50.8MM) WIDTH; HEIGHT AS REQUIRED); BEND TO FORM RIGHT ANGLE

SAME FASTENERS AS SLAB SIDE MOUNTING.

ONE BRACKET PER SIDE (MIN.); FOR EXTRA STABILITY, TWO BRACKETS PER SIDE, 2” (50.8MM) FROM EACH CORNER.

PER SIDE

FOR EXTRA

STABILITY

Stabilizing Unit on Uneven Surfaces

IMPORTANT - To help stabilize an outdoor unit, some installations may require strap

ping the unit to the pad using brackets and anchors commonly available in the marketplace.

COIL

BASE PAN

Figure 5. Placement and Slab Mounting

XC20

Page 12

Removing and Installing Panels

LOUVERED PANEL REMOVAL

Remove the louvered panels as follows:

1. Remove two screws, allowing the panel to swing open slight ly.

2. Hold the panel firmly throughout this procedure. Rotate bot tom corner of panel away from hinged corner post until lower three tabs clear the slots as illustrated in Detail B.

3. Move panel down until lip of upper tab clears the top slot in corner post as illustrated in Detail A.

LOUVERED PANEL INSTALLATION

Position the panel almost parallel with the unit as illustrated in Detail D with the screw side as close to the unit as possible. Then, in a continuous motion:

1. Slightly rotate and guide the lip of the top tab inward as

illustrated in Detail A and C; then upward into the top slot of the hinge corner post.

2. Rotate the panel until it is completely vertical to fully en gage all of the tabs.

3. Holding the panel's hinged side firmly in place, close the right-hand side of the panel, aligning the screw holes.

4. When panel is correctly positioned and aligned, insert the screws and tighten.

IMPORTANT ALIGNMENT AND NOT DESIGNED TO SUPPORT WEIGHT OF PANEL.

PANEL SHOWN SLIGHTLY ROTATED TO ALLOW TOP TAB TO EXIT (OR ENTER) TOP SLOT FOR REMOVING (OR INSTALLING) PANEL.

! DO NOT ALLOW PANELS TO HANG ON UNIT BY TOP TAB. TAB IS FOR

SCREW

LIP

HOLES

Detail A

Detail B

ROTATE IN THIS DIRECTION;

ANGLE MAY BE TOO EXTREME

THEN DOWN TO REMOVE

SIDE TO MAINTAIN FULLY-ENGAGED TABS

PANEL

HOLD DOOR FIRMLY TO THE HINGED

Detail C

MAINTAIN MINIMUM PANEL ANGLE (AS CLOSE TO PARALLEL WITH THE UNIT AS POSSIBLE) WHILE INSTALLING PANEL.

Figure 6. Removing and Installing Panels

PREFERRED ANGLE FOR INSTALLATION

XC20

Page 13

New or Replacement Line Set

REFRIGERANT LINE SET

This section provides information on installation or replace

ment of existing line set. If new or replacement line set is

not being installed then proceed to Brazing Connections on

page 16.

IMPORTANT

Lennox highly recommends changing line set when converting the existing system from HCFC-22 to HFC-410A If that is not possible and the line set is the proper size as referenced in table 2, use the procedure outlined under Flushing the System on page 19.

If refrigerant lines are routed through a wall, seal and isolate

the opening so vibration is not transmitted to the building.

Pay close attention to line set isolation during installation of

any HVAC system. When properly isolated from building

structures (walls, ceilings, floors), the refrigerant lines will

not create unnecessary vibration and subsequent sounds.

See figure 7 for recommended installation practices. Also,

consider the following when placing and installing a high-

efficiency outdoor unit.

Liquid lines that meter the refrigerant, such as RFC1 liquid

lines, must not be used in this application. Existing line set

of proper size may be reused. If system was previously

charged with HCFC-22 refrigerant, then existing line set

must be flushed (see Flushing the System on page 19).

IMPORTANT

Mineral oils are not compatible with HFC-410A. If oil

must be added, it must be a Polyol ester oil.

IMPORTANT !

If this unit is being matched with an approved line set or indoor unit coil that was previously charged with mineral oil, or if it is being matched with a coil which was manufactured before January of 1999, the coil and line set must be flushed prior to installation. Take care to empty all existing traps. Polyol ester (POE) oils are used in Lennox units charged with HFC-410A refrigerant. Residual mineral oil can act as an insulator, preventing proper heat transfer. It can also clog the expansion device and reduce system performance and capacity.

Failure to properly flush the system per the XC20 Installation and Service Procedures will void the warranty.

WARNING

Refrigerant can be harmful if it is inhaled. Refrigerant must be used and recovered responsibly.

Failure to follow this warning may result in personal injury or death.

WARNING

Fire, Explosion and Personal Safety Hazard. Failure to follow this warning could result in damage, personal inju ry or death.

Never use oxygen to pressurize or purge refrigeration lines. Oxygen, when exposed to a spark or open flame, can cause fire and/or an ex plosion, that could result in property damage, personal injury or death.

WARNING

When using a high pressure gas such as nitrogen to pressurize a refrigeration or air conditioning system, use a regulator that can control the pressure down to 1 or 2 psig (6.9 to 13.8 kPa).

Recommended POE oils are Mobil EAL ARCTIC 22 CC or

ICI EMKARATEt RL32CF.

WARNING

Danger of fire. Bleeding the refrigerant charge from only the high side may result in the low side shell and suction tubing being pressurized. Application of a brazing torch while pressurized may result in ignition of the refrigerant and oil mixture - check the high and low pressures before unbrazing.

IMPORTANT !

Some scroll compressors have an internal vacuum protector that will unload scrolls when suction pres sure goes below 20 psig. A hissing sound will be heard when the compressor is running unloaded. Protector will reset when low pressure in system is raised above 40 psig. DO NOT REPLACE COMPRES SOR.

The XC20 is a variable-capacity cooling system utilizing variable-speed compressor technology. With the variablespeed compressor and variable pumping capacity, additional consideration must be given to refrigerant piping sizing and application. The following guidelines are to be used exclusively for the XC20 systems.

XC20

Page 14

COOLING SYSTEM (HFC410A)

D Total equivalent length equals 180 feet (all piping and

fittings included).

NOTE - This is a general guide. Lengths may be more or less, depending on remaining system design factors.

D Maximum linear (actual) length = 150 feet. D Maximum linear liquid lift = 60 feet.

NOTE - Maximum lifts are dependent on total length, num ber of elbows, and other factors that contribute to total pressure drop.

D Maximum linear length of vapor riser = 60 feet. D Size vertical vapor riser per table 2. D Line set lengths up to 50 linear feet: Use rated line

sizes listed in table 2.

D Line set lengths between 51 and 150 linear feet:

Crankcase heater and nonbleed port TXV factory-in

stalled. No additional components required. Vertical vapor riser must be sized to the vapor riser listed in table 3 on systems with line sets longer than 51 feet. Use tables 3 and 4 to determine the correct liquid and vapor line sizes.

D Line set lengths over 150 linear feet: Not recom

mended.

D Additional oil is not required for systems with line

lengths up to 150 feet.

NOTE - Recommended POE oils are Mobil EAL ARCTIC 22 CC or ICI EMKARATEt RL32CF.

SUCTION TRAPS

In systems with the outdoor unit 5 to 60 feet above the in door unit, one trap must be installed at the bottom of the suction riser.

Table 2. Standard Refrigerant Line Set — Up to 50 Linear Feet

Valve Size Connections Recommended Line Sets

Model Number (-xx*)

XC20-024-230-XX 3/8” (10 mm) 3/4” (19 mm) L15-41-30 30 feet (9.1 m) 89J60

XC20-036-230-XX XC20-048-230-XX

XC20-060-230-XX 3/8” (10 mm) 1-1/8” (29 mm) ** Field-fabricated

* Applicable to all minor revision numbers unless otherwise specified. ** Some applications may require a field-provided 1-1/8” to 7/8” adapter.

Liquid Line Suction Line

3/8” (10 mm) 7/8” (22 mm)

L15 Line Set Model

L15-65-40 40 feet (12.2 m) 89J61

L15-65-50 50 feet (15.2 m) 89J62

Line Set Length

Catalog Number

Table 3. XC20 Line Set Guidelines — 51 to 150 Linear Feet in Length

Model

024 180 150 60 60 3/4” 5/8”

036 180 150 60 60 7/8” 3/4”

048 180 150 60 60 7/8” 7/8”

060 180 150 60 60 7/8” 7/8”

Maximum Total

Equivalent Length (ft)

Maximum Linear

(actual) Length (ft)

Maximum Vapor

Riser (ft)

Maximum

Linear Liquid

Lift (ft)

Preferred Vapor Line

Sizes for Horizontal

Runs

Required Vapor

Riser Size

Table 4. Liquid Line Diameter Selection Table

Total Linear Length (feet)

Unit

024

036

048

060

Line Size

5/16” 25 50 55 48 40 33

3/8” 25 50 60 60 60 60

3/8” 25 50 60 56 51 45

1/2” 25 50 60 60 60 60

3/8” 25 50 50 41 31 22

1/2” 25 50 60 60 60 60

3/8” 25 50 36 22 8 NR

1/2”

25 50 75 100 125 150

50 60 60 60 59

Note  Shaded rows indicate rated liquid line size.

1. Find your unit on the left side of the table.

2. Start with the rated liquid line size (shaded row) for the outdoor unit.

3. Select the actual total linear length of your system shown at the top of the table.

4. The elevation listed in the table is the maximum allowed for the liquid line listed.

5. Consider the larger liquid line size shown in the table if the elevation does not meet your requirements.

Max. Elevation

(ft)

XC20

Page 15

LINE SET

INSTALLATION

LINE SET ISOLATION — THE FOLLOWING ILLUSTRATIONS ARE EXAM

PLES OF PROPER REFRIGERANT LINE SET ISOLATION:

REFRIGERANT LINE SET — TRANSITION

FROM VERTICAL TO HORIZONTAL

ANCHORED HEAVY NYLON WIRE TIE OR AUTOMOTIVE

MUFFLER‐TYPE HANGER

AUTOMOTIVE

MUFFLER‐TYPE HANGER

IMPORTANT - Refrigerant lines must not contact structure.

REFRIGERANT LINE SET — INSTALLING

VERTICAL RUNS (NEW CONSTRUCTION SHOWN)

NOTE - INSULATE LIQUID LINE WHEN IT IS ROUTED THROUGH AREAS WHERE THE SURROUNDING AMBIENT TEMPERATURE COULD BECOME HIGHER THAN THE TEMPERATURE OF THE LIQUID LINE OR WHEN PRESSURE DROP IS EQUAL TO OR GREATER THAN 20 PSIG.

IMPORTANT - Refrigerant lines must not contact wall

OUTSIDE WALL

VAPOR LINE

LIQUID LINE

WALL STUD

STRAP LIQUID LINE TO VAPOR LINE

LIQUID LINE

NON-CORROSIVE

METAL SLEEVE

VAPOR LINE - WRAPPED IN ARMAFLEX

REFRIGERANT LINE SET — INSTALLING

HORIZONTAL RUNS

TO HANG LINE SET FROM JOIST OR RAFTER, USE EITHER METAL STRAPPING MATERIAL OR ANCHORED HEAVY NYLON WIRE TIES.

WIRE TIE (AROUND VAPOR LINE ONLY)

8 FEET (2.43 METERS)

STRAPPING

MATERIAL (AROUND

VAPOR LINE ONLY)

TAPE OR WIRE TIE

FLOOR JOIST OR

ROOF RAFTER

8 FEET (2.43 METERS)

NON-CORROSIVE METAL SLEEVE

STRAP THE VAPOR LINE TO THE JOIST OR RAFTER AT 8 FEET (2.43 METERS) INTERVALS THEN STRAP THE LIQUID LINE TO THE VAPOR LINE.

TAPE OR WIRE TIE

WIRE TIE

INSIDE WALL

WOOD BLOCK

BETWEEN

STUDS

SLEEVE

VAPOR LINE WRAPPED

WITH ARMAFLEX

OUTSIDE

WALL

PVC

PIPE

FIBERGLASS

INSULATION

NOTE - SIMILAR INSTALLATION PRACTICES SHOULD BE USED IF LINE SET IS TO BE INSTALLED ON EXTERIOR OF OUTSIDE WALL.

CAULK

STRAP

NON-CORROSIVE METAL SLEEVE

WIRE TIE

WOOD BLOCK

WIRE TIE

STRAP

LIQUID LINE

FLOOR JOIST OR

ROOF RAFTER

WARNING - Polyol ester (POE) oils used with HFC-410A refrigerant absorb moisture very quickly. It is very important that the refrigerant system be kept closed as much as possible. DO NOT remove line set caps or service valve stub caps until you are ready to make connections.

Figure 7. Line Set Installation

XC20

Page 16

Brazing Connections

Use the procedures outlined in figures 8 and 9 for brazing line set connections to service valves.

WARNING

IMPORTANT

Allow braze joint to cool before removing the wet rag from the service valve. Temperatures above 250ºF can damage valve seals.

Danger of fire. Bleeding the refrigerant charge from only the high side may result in pressurization of the low side shell and suction tubing. Application of a brazing torch to a pressurized system may result in ignition of the refrigerant and oil mixture

- Check the high and low pressures before applying heat.

CAUTION

Brazing alloys and flux contain materials which are hazardous to your health.

Avoid breathing vapors or fumes from brazing operations. Perform operations only in well-ventilated areas.

Wear gloves and protective goggles or face shield to protect against burns.

Wash hands with soap and water after handling brazing alloys and flux.

WARNING

Fire, Explosion and Personal Safety Hazard.

Failure to follow this warning could re sult in damage, personal injury or death.

Never use oxygen to pressurize or purge refrigeration lines. Oxygen, when exposed to a spark or open flame, can cause a fire and/or an explosion, that could result in property damage, per sonal injury or death.

XC20

Page 17

PIPING PANEL REMOVAL AND LINE SET PREPARATION

Remove piping panel for easier access to service valves. Cut ends of the refrigerant lines square (free from nicks or dents) and debur the ends. The pipe must remain round. Do not crimp end of the line.

CUT AND DEBUR

LINE SET SIZE MATCHES

SERVICE VALVE CONNECTION

SERVICE VALVE

COPPER TUBE

REDUCER

STUB

CONNECTION

LINE SET SIZE IS SMALLER

THAN CONNECTION

CAP AND CORE REMOVAL

Remove service cap and core from both the suction and liquid line

service ports.

SERVICE PORT CAP

SERVICE PORT CORE

LIQUID LINE SERVICE VALVE

REFRIGERANT LINE

DO NOT CRIMP SERVICE

VALVE CONNECTOR WHEN

PIPE IS SMALLER THAN

CONNECTION

ATTACH THE MANIFOLD GAUGE SET FOR BRAZING LIQUID AND SUCTION LINE SERVICE VALVES

A. Connect gauge set low pressure side to liquid line

service valve (service port).

B. Connect gauge set center port to bottle of nitrogen

with regulator.

C. With valve core removed from the suction line service

port, nitrogen flow will have an exit point.

SUCTION SERVICE PORT MUST BE OPEN AND

SERVICE PORT CORE REMOVED TO ALLOW

EXIT POINT FOR NITROGEN FLOW

SUCTION LINE

INDOOR

UNIT

SUCTION LINE

SERVICE VALVE

SUCTION LINE SERVICE

VALV E

LOW

ATTACH

GAUGES

OUTDOOR

UNIT

HIGH

SERVICE PORT CORE

SERVICE PORT CAP

LIQUID LINE

LIQUID LINE SERVICE

VALV E

Figure 8. Brazing Procedures

NITROGEN

XC20

Page 18

WRAP SERVICE VALVES

To help protect service valve seals during brazing, wrap water-saturated cloths around service valve bodies and copper tube stubs. Use

additional water-saturated cloths underneath the valve body to protect the base paint.

FLOW NITROGEN

Flow regulated nitrogen (at 1 to 2 psig) through the refrigeration gauge set into the valve stem port connection on the liquid service valve

and out of the suction / vapor valve stem port. See steps 3A, 3B and 3C on manifold gauge set connections.

BRAZE LINE SET

Wrap both service valves with water-saturated cloths as illustrated here and as mentioned in step 4, before brazing to line set. Cloths

must remain water-saturated throughout the brazing and cool-down process.

LIQUID LINE SERVICE VALVE

WHEN BRAZING LINE SET TO

SERVICE VALVES, POINT FLAME

AWAY FROM SERVICE VALVE.

IMPORTANT - Allow braze joint to cool. Apply additional

water-saturated cloths to help cool brazed joint. Do not remove water-saturated cloths until piping has cooled. Temperatures above 250ºF will damage valve seals.

LIQUID LINE

WATER-SATURATED CLOTH

WARNING

FIRE, PERSONAL INJURY, OR PROPERTY DAMAGE

may result if you do not wrap a water-saturated cloth around both liquid and suction line service valve bodies and copper tube stub while brazing the line set! The braze, when complete, must be quenched with water to absorb any residual heat.

Do not open service valves until refrigerant lines and indoor coil have been leak-tested and evacuated. Refer to Installation and Service Procedures manual found on DAVENET.

SUCTION LINE

PREPARATION FOR NEXT STEP

Disconnect manifold gauge set from service ports after all connections have been brazed. Apply additional water-saturated cloths to both

service valves to cool piping. Once piping is cool, remove all water-saturated cloths.

SUCTION LINE SERVICE

VALV E

SERVICE VALVES, POINT FLAME

WATER-SATURATED CLOTH

WHEN BRAZING LINE SET TO

AWAY FROM SERVICE VALVE.

Figure 9. Brazing Procedures (Continued)

XC20

Page 19

Flushing the System

LINE SET AND INDOOR COIL (1 OF 2)

TYPICAL EXISTING EXPANSION VALVE REMOVAL PROCEDURE (UNCASED COIL

TWO PIECE PATCH PLATE

TYPICAL EXISTING FIXED ORIFICE REMOVAL PROCEDURE (UNCASED COIL

DISTRIBUTOR

ASSEMBLY

A. ON FULLY CASED COILS, REMOVE THE COIL ACCESS AND PLUMBING

PANELS.

B. REMOVE ANY SHIPPING CLAMPS HOLDING THE LIQUID LINE AND DIS

TRIBUTOR ASSEMBLY.

C. USING TWO WRENCHES, DISCONNECT LIQUID LINE FROM LIQUID LINE

ORIFICE HOUSING. TAKE CARE NOT TO TWIST OR DAMAGE DISTRIBU TOR TUBES DURING THIS PROCESS.

D. REMOVE AND DISCARD FIXED ORIFICE, VALVE STEM ASSEMBLY (IF

PRESENT) AND TEFLON

E. USE A FIELD-PROVIDED FITTING TO TEMPORARILY RECONNECT THE

LIQUID LINE TO THE INDOOR UNIT'S LIQUID LINE ORIFICE HOUSING.

SHOWN)

DISTRIBUTOR TUBES

REMOVE AND DISCARD

WHITE TEFLON

LIQUID LINE ORIFICE HOUSING

TEFLON® RING

FIXED ORIFICE

BRASS NUT

(IF PRESENT)

WASHER AS ILLUSTRATED ABOVE.

SEAL

LIQUID LINE ASSEMBLY

(INCLUDES STRAINER)

CONNECT GAUGES AND EQUIPMENT FOR FLUSHING PROCEDURE

INV ERT ED HCFC-22 CYLINDER CONTAINS CLE AN HCFC-22* TO BE USED FOR FLUSHING.

VAPOR LINE

SERVICE VALVE

EXISTING

INDOOR

UNIT

LIQUID LINE SERVICE

RECOVERY

CYLINDER

VALV E

VAPOR

LIQUID

NEW

OUTDOOR

UNIT

OPENED

A. INVERTED HCFC-22 CYLINDER WITH CLEAN REFRIGERANT* TO THE

VAPOR SERVICE VALVE.

B. HCFC-22 GAUGE SET (LOW SIDE) TO THE LIQUID LINE VALVE.

C. HCFC-22 GAUGE SET CENTER PORT TO INLET ON THE RECOVERY

MACHINE WITH AN EMPTY RECOVERY TANK TO THE GAUGE SET.

D. CONNECT RECOVERY TANK TO RECOVERY MACHINE PER MACHINE

INSTRUCTIONS.

*IMPORTANT - Clean refrigerant is any refrigerant in a system that has not had compressor burn out. If the system has experienced burn out, it is recommended that the existing line set and indoor coil be replaced.

RECOVERY MACHINE

MANIFOLD

LOW

TANK RETURN

INLET

DISCHARGE

GAUGE

CLOSED

(UNCASED COIL ONLY)

HIGH

SHOWN)

LIQUID LINE

DISTRIBUTOR

TUBES

DISTRIBUTOR

ASSEMBLY

MALE EQUALIZER

LINE FITTING

SENSING BULB

A. ON FULLY CASED COILS, REMOVE THE COIL ACCESS AND PLUMBING

PANELS.

B. REMOVE ANY SHIPPING CLAMPS HOLDING THE LIQUID LINE AND DIS

TRIBUTOR ASSEMBLY.

C. DISCONNECT THE EQUALIZER LINE FROM THE CHECK EXPANSION

VALVE EQUALIZER LINE FITTING ON THE VAPOR LINE.

D. REMOVE THE VAPOR LINE SENSING BULB.

E. DISCONNECT THE LIQUID LINE FROM THE CHECK EXPANSION VALVE

AT THE LIQUID LINE ASSEMBLY.

F. DISCONNECT THE CHECK EXPANSION VALVE FROM THE LIQUID LINE

ORIFICE HOUSING. DO NOT TO TWIST OR DAMAGE DISTRIBUTOR TUBES DURING THIS PROCESS.

G. REMOVE AND DISCARD CHECK EXPANSION VALVE AND THE TWO TEF

H. USE A FIELD-PROVIDED FITTING TO TEMPORARILY RECONNECT THE

RINGS.

LON

LIQUID LINE TO THE INDOOR UNIT'S LIQUID LINE ORIFICE HOUSING.

ORIFICE

HOUSING

EQUALIZER LINE

STUB END

TEFLON RING

VAPOR

CHECK

EXPANSION

VALV E

LIQUID LINE

ASSEMBLY WITH

BRASS NUT

LINE

TEFLON

RING

FLUSHING LINE SET

CAUTION -This procedure should not be performed on systems

which contain contaminants (Example, compressor burn out).

THE LINE SET AND INDOOR UNIT COIL MUST BE FLUSHED WITH AT LEAST THE SAME AMOUNT OF CLEAN REFRIGERANT* THAT PRE VIOUSLY CHARGED THE SYSTEM. CHECK THE CHARGE IN THE FLUSHING CYLINDER BEFORE PROCEEDING.

A. SET THE RECOVERY MACHINE FOR LIQUID RECOVERY AND

START THE RECOVERY MACHINE. OPEN THE GAUGE SET VALVES TO ALLOW THE RECOVERY MACHINE TO PULL A VACU UM ON THE EXISTING SYSTEM LINE SET AND INDOOR UNIT COIL.

B. INVERT THE CYLINDER OF CLEAN HCFC-22* AND OPEN ITS

VALVE TO ALLOW LIQUID REFRIGERANT TO FLOW INTO THE SYS TEM THROUGH THE VAPOR LINE VALVE. ALLOW THE REFRIGER ANT TO PASS FROM THE CYLINDER AND THROUGH THE LINE SET AND THE INDOOR UNIT COIL BEFORE IT ENTERS THE RECOVERY MACHINE.

C. AFTER ALL OF THE LIQUID REFRIGERANT HAS BEEN RECOV

ERED, SWITCH THE RECOVERY MACHINE TO VAPOR RECOVERY SO THAT ALL OF THE HCFC-22 VAPOR IS RECOVERED. ALLOW THE RECOVERY MACHINE TO PULL SYSTEM DOWN TO 0.

D. CLOSE THE VALVE ON THE INVERTED HCFC-22 DRUM AND THE

GAUGE SET VALVES. PUMP THE REMAINING REFRIGERANT OUT OF THE RECOVERY MACHINE AND TURN OFF THE MACHINE.

SENSING

LINE

LIQUID

LINE

XC20

Page 20

FLUSHING LINE SET AND INDOOR COIL (2 OF 2)

TYPICAL NEW CHECK EXPANSION VALVE INSTALLATION PROCEDURE

THIS OUTDOOR UNIT IS DESIGNED FOR USE IN SYSTEMS THAT USE A CHECK EXPANSION VALVE METERING DEVICE. SEE LENNOX XC20 PRODUCT SPECIFICATIONS FOR APPROVED EXPANSION VALVE KIT MATCH-UPS AND APPLICATION INFORMATION.

THE EXPANSION VALVE UNIT CAN BE INSTALLED INTERNAL OR EXTERNAL TO THE INDOOR COIL. IN APPLICATIONS WHERE AN

TWO PIECE

PATCH PLATE

(UNCASED

COIL ONLY)

DISTRIBUTOR

TUBES

DISTRIBUTOR

ASSEMBLY

MALE EQUALIZER LINE

FITTING (SEE

EQUALIZER LINE INSTALLATION FOR FURTHER DETAILS)

SENSING BULB INSULATION IS REQUIRED IF MOUNTED EXTERNAL TO THE COIL CASING. SEE SENSING BULB INSTALLATION FOR BULB POSITIONING.

(Uncased Coil Shown)

LIQUID LINE

ORIFICE

HOUSING

STUB

END

TEFLON RING

EQUALIZER LINE

EXPANSION

VALV E

LIQUID LINE

ASSEMBLY WITH

BRASS NUT

VAPOR

LINE

UNCASED COIL IS BEING INSTALLED IN A FIELD-PROVIDED PLENUM, INSTALL THE CHECK EXPANSION VALVE IN A MANNER THAT WILL PROVIDE ACCESS FOR FIELD SERVICING OF THE EXPANSION VALVE. REFER TO BELOW ILLUSTRATION FOR REFERENCE DURING INSTALLATION OF EXPANSION VALVE UNIT.

TEFLON

RING

A. REMOVE THE FIELD-PROVIDED FITTING THAT TEMPORARILY RECON

NECTED THE LIQUID LINE TO THE INDOOR UNIT'S DISTRIBUTOR AS

SENSING

LINE

LIQUID LINE

SEMBLY.

B. INSTALL ONE OF THE PROVIDED TEFLON

STUBBED END OF THE EXPANSION VALVE AND LIGHTLY LUBRICATE THE CONNECTOR THREADS AND EXPOSE SURFACE OF THE TEFLON RING WITH REFRIGERANT OIL.

C. ATTACH THE STUBBED END OF THE EXPANSION VALVE TO THE LIQUID

LINE ORIFICE HOUSING. FINGER TIGHTEN AND USE AN APPROPRIATELY SIZED WRENCH TO TURN AN ADDITIONAL 1/2 TURN CLOCKWISE AS IL LUSTRATED IN THE FIGURE ABOVE, OR 20 FT-LB.

D. PLACE THE REMAINING TEFLON

OF THE EXPANSION VALVE. LIGHTLY LUBRICATE CONNECTOR THREADS AND EXPOSE SURFACE OF THE TEFLON FRIGERANT OIL.

E. ATTACH THE LIQUID LINE ASSEMBLY TO THE EXPANSION VALVE. FIN

GER TIGHTEN AND USE AN APPROPRIATELY SIZED WRENCH TO TURN AN ADDITIONAL 1/2 TURN CLOCKWISE AS ILLUSTRATED IN THE FIGURE ABOVE OR 20 FT-LB.

9 O'CLOCK TO

3 O'CLOCK

BULB

WASHER AROUND THE OTHER END

RINGS AROUND THE

ON LINES SMALLER THAN 7/8”, MOUNT SENSING BULB BETWEEN THE 9 AND 3 O'CLOCK POSITIONS.

SENSING BULB INSTALLATION

VAPOR LINE

A. ATTACH THE VAPOR LINE SENSING BULB IN THE PROPER

ORIENTATION AS ILLUSTRATED TO THE RIGHT USING THE CLAMP AND SCREWS PROVIDED.

NOTE - CONFIRM PROPER THERMAL CONTACT BETWEEN VAPOR LINE AND CHECK EXPANSION BULB BEFORE INSU LATING THE SENSING BULB ONCE INSTALLED.

B. CONNECT THE EQUALIZER LINE

FROM THE EXPANSION VALVE TO THE EQUALIZER VAPOR PORT ON THE VAPOR LINE. FINGER TIGHTEN THE FLARE NUT PLUS 1/8 TURN (7 FT-LBS) AS ILLUS TRATED BELOW.

1/8 TURN

VAPOR LINE

BULB

FLARE SEAL CAP

ON 7/8” AND LARGER LINES, MOUNT SENSING BULB AT EITHER THE 4 OR 8 O'CLOCK POSITION. NEVER MOUNT

BULB

NOTE - NEVER MOUNT THE SENSING BULB ON

BOTTOM OF LINE.

THE SENSING BULB ON BOTTOM OF LINE.

FLARE NUT

1/2 TURN

RING WITH RE

EQUALIZER LINE INSTALLATION

REMOVE AND DISCARD EITHER THE FLARE SEAL CAP OR FLARE NUT WITH COPPER FLARE SEAL BONNET FROM THE EQUALIZER LINE PORT ON THE VAPOR LINE AS ILLUSTRATED IN THE FIGURE TO THE RIGHT.

XC20

COPPER FLARE SEAL BONNET

MALE BRASS EQUALIZER LINE FITTING

VAPOR LINE

Page 21

IMPORTANT

Leak Testing the System

The Environmental Protection Agency (EPA) prohibits the intentional venting of HFC refrigerants during maintenance, service, repair and disposal of appliance. Approved methods of recovery, recycling or reclaiming must be followed.

IMPORTANT

If this unit is being matched with an approved line set or indoor unit coil which was previously charged with mineral oil, or if it is being matched with a coil which was manufactured before January of 1999, the coil and line set must be flushed prior to installation. Take care to empty all existing traps. Polyol ester (POE) oils are used in Lennox units charged with HFC-410A refrigerant. Residual mineral oil can act as an insulator, preventing proper heat transfer. It can also clog the expansion device, and reduce the system performance and capacity. Failure to properly flush the system per the instructions below will void the warranty.

IMPORTANT

Leak detector must be capable of sensing HFC refrigerant.

WARNING

Refrigerant can be harmful if it is inhaled. Refrigerant must be used and recovered responsibly.

Failure to follow this warning may result in personal injury or death.

XC20

Page 22

LEAK TEST

LINE SET AND INDOOR COIL

NOTE - NORMALLY, THE HIGH PRESSURE HOSE IS CONNECTED TO THE LIQUID LINE PORT. HOWEVER, CONNECTING IT TO THE VAPOR PORT BETTER PROTECTS THE MANIFOLD GAUGE SET FROM HIGH PRESSURE DAMAGE.

LOW

HIGH

CONNECT GAUGE SET

A. CONNECT AN HFC-410A MANIFOLD GAUGE SET HIGH PRESSURE

HOSE TO THE VAPOR VALVE SERVICE PORT.

B. WITH BOTH MANIFOLD VALVES CLOSED, CONNECT THE CYLINDER

OF HFC-410A REFRIGERANT TO THE CENTER PORT OF THE MANIFOLD GAUGE SET.

NOTE - LATER IN THE PROCEDURE, THE HFC-410A CONTAINER WILL BE REPLACED BY THE NITROGEN CONTAINER.

NITROGEN

TEST FOR LEAKS

AFTER THE LINE SET HAS BEEN CONNECTED TO THE INDOOR AND OUTDOOR UNITS, CHECK THE LINE SET CON NECTIONS AND INDOOR UNIT FOR LEAKS. USE THE FOLLOWING PROCEDURE TO TEST FOR LEAKS:

A. WITH BOTH MANIFOLD VALVES CLOSED, CONNECT THE CYLINDER OF HFC-410A REFRIGERANT TO THE CENTER PORT OF THE

MANIFOLD GAUGE SET. OPEN THE VALVE ON THE HFC-410A CYLINDER (VAPOR ONLY).

B. OPEN THE HIGH PRESSURE SIDE OF THE MANIFOLD TO ALLOW HFC-410A INTO THE LINE SET AND INDOOR UNIT. WEIGH IN A TRACE

AMOUNT OF HFC-410A [A TRACE AMOUNT IS A MAXIMUM OF TWO OUNCES (57 G) REFRIGERANT OR THREE POUNDS (31 KPA) PRES SURE]. CLOSE THE VALVE ON THE HFC-410A CYLINDER AND THE VALVE ON THE HIGH PRESSURE SIDE OF THE MANIFOLD GAUGE SET. DISCONNECT THE HFC-410A CYLINDER.

C. CONNECT A CYLINDER OF DRY NITROGEN WITH A PRESSURE REGULATING VALVE TO THE CENTER PORT OF THE MANIFOLD

GAUGE SET.

D. ADJUST DRY NITROGEN PRESSURE TO 150 PSIG (1034 KPA). OPEN THE VALVE ON THE HIGH SIDE OF THE MANIFOLD GAUGE SET IN

ORDER TO PRESSURIZE THE LINE SET AND THE INDOOR UNIT.

E. 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.

F. AFTER LEAK TESTING, DISCONNECT GAUGES FROM SERVICE PORTS.

HFC-410A

MANIFOLD GAUGE SET

TO VAPOR

SERVICE VALVE

OUTDOOR UNIT

XC20

Figure 10. System Leak Test

Page 23

Evacuating the System

LINE SET AND INDOOR COIL

CONNECT GAUGE SET

NOTE - REMOVE CORES FROM SERVICE VALVES (IF NOT ALREADY DONE).

A. CONNECT LOW SIDE OF MANIFOLD

GAUGE SET WITH 1/4 SAE IN-LINE TEE TO VAPOR LINE SERVICE VALVE.

B. CONNECT HIGH SIDE OF MANIFOLD

GAUGE SET TO LIQUID LINE SERVICE VALVE.

C. CONNECT MICRON GAUGE TO AN

AVAILABLE CONNECTOR ON THE 1/4 SAE IN-LINE TEE.

D. CONNECT THE VACUUM PUMP (WITH

VACUUM GAUGE) TO THE CENTER PORT OF THE MANIFOLD GAUGE SET. THE CENTER PORT LINE IS USED LATER FOR BOTH THE AND NITROGEN CONTAINERS.

OUTDOOR

UNIT

A34000 1/4 SAE TEE WITH SWIVEL COUPLER

500

MICRON

GAUGE

LOW

TO VAPOR

SERVICE VALVE

MANIFOLD

GAUGE SET

HIGH

HFC-410A

VACUUM PUMP

TO LIQUID LINE SERVICE VALVE

NITROGEN

EVACUATE THE SYSTEM

A. OPEN BOTH MANIFOLD VALVES AND START THE VACUUM PUMP.

B. EVACUATE THE LINE SET AND INDOOR UNIT TO AN ABSOLUTE PRESSURE OF 23,000 MICRONS (29.01 INCHES OF MERCURY).

NOTE - DURING THE EARLY STAGES OF EVACUATION, IT IS DESIRABLE TO CLOSE THE MANIFOLD GAUGE VALVE AT LEAST ONCE. A RAPID RISE IN PRESSURE INDICATES A RELATIVELY LARGE LEAK. IF THIS OCCURS, REPEAT THE LEAK TESTING PROCEDURE.

NOTE - THE TERM ABSOLUTE PRESSURE REFERS TO THE TOTAL ACTUAL PRESSURE (ABOVE ABSOLUTE ZERO) WITHIN A GIVEN VOLUME OR SYSTEM. ABSOLUTE PRESSURE IN A VACUUM IS EQUAL TO ATMOSPHERIC PRESSURE MINUS VACUUM PRESSURE.

C. WHEN THE ABSOLUTE PRESSURE REACHES 23,000 MICRONS (29.01 INCHES OF MERCURY), CLOSE THE MANIFOLD GAUGE VALVES, TURN

OFF THE VACUUM PUMP AND DISCONNECT THE MANIFOLD GAUGE CENTER PORT HOSE FROM VACUUM PUMP. ATTACH THE MANIFOLD CENTER PORT HOSE TO A DRY NITROGEN CYLINDER WITH PRESSURE REGULATOR SET TO 150 PSIG (1034 KPA) AND PURGE THE HOSE. OPEN THE MANIFOLD GAUGE VALVES TO BREAK THE VACUUM IN THE LINE SET AND INDOOR UNIT. CLOSE THE MANIFOLD GAUGE VALVES.

D. SHUT OFF THE DRY NITROGEN CYLINDER AND REMOVE THE MANIFOLD GAUGE HOSE FROM THE CYLINDER. OPEN THE MANIFOLD

GAUGE VALVES TO RELEASE THE DRY NITROGEN FROM THE LINE SET AND INDOOR UNIT.

E. RECONNECT THE MANIFOLD GAUGE TO THE VACUUM PUMP, TURN THE PUMP ON, AND CONTINUE TO EVACUATE THE LINE SET AND IN

DOOR UNIT UNTIL THE ABSOLUTE PRESSURE DOES NOT RISE ABOVE 500 MICRONS (29.9 INCHES OF MERCURY) WITHIN A 20-MINUTE PERIOD AFTER SHUTTING OFF THE VACUUM PUMP AND CLOSING THE MANIFOLD GAUGE VALVES.

F. WHEN THE ABSOLUTE PRESSURE REQUIREMENT ABOVE HAS BEEN MET, DISCONNECT THE MANIFOLD HOSE FROM THE VACUUM PUMP

AND CONNECT IT TO AN UPRIGHT CYLINDER OF HFC-410A REFRIGERANT. OPEN THE MANIFOLD GAUGE VALVE 1 TO 2 PSIG IN ORDER TO RELEASE THE VACUUM IN THE LINE SET AND INDOOR UNIT.

G. PERFORM THE FOLLOWING:

1. Close manifold gauge valves.

. Shut off HFC-410A cylinder. . Reinstall service valve cores by removing manifold hose from service valve. Quickly install cores with core

tool while maintaining a positive system pressure.

. Replace the stem caps and secure finger tight, then tighten an additional one-sixth (1/6) of a turn as illus

trated.

RECOMMEND

MINIMUM 3/8” HOSE

1/6 TURN

Figure 11. Evacuating System

XC20

Page 24

IMPORTANT

Load Shedding

Use a thermocouple or thermistor electronic vacuum gauge that is calibrated in microns. Use an instrument capable of accurately measuring down to 50 microns.

WARNING

Danger of Equipment Damage. Avoid deep vacuum operation. Do not use compressors to evacuate a system. Extremely low vacuums can cause internal arcing and compressor failure. Damage caused by deep vacuum operation will void warranty.

Evacuating the system of non-condensables is critical for proper operation of the unit. Non-condensables are defined as any gas that will not condense under temperat ures and pressures present during operation of an air conditioning system. Non-condensables combine with re frigerant to produce substances that corrode copper piping and compressor parts.

Electrical

In the U.S.A., wiring must conform with current local codes and the current National Electric Code (NEC). In Canada, wiring must conform with current local codes and the current Canadian Electrical Code (CEC).

Refer to the furnace or air handler installation instructions for additional wiring application diagrams. Refer to unit nameplate for minimum circuit ampacity and maximum over-current protection size.

24VAC TRANSFORMER

Use the transformer provided with the furnace or air hand ler for low‐voltage control power (24VAC - 40 VA minimum).

Utility Load Shedding Mode ACTIVATED (Utility Cycled Unit OFF) – The normally closed set of

contacts in the utility load shedding control receiver OPEN. This removes 24VAC from the coil of the field-provided re lay (catalog # 69J79). The relay contacts close (terminal 7 to terminal 2), completing the circuit between terminals R and L on the outdoor control. The 24VAC input to terminal L activates the load-shedding mode in the outdoor control, cycling the outdoor unit OFF. The 7-Segment display on the outdoor control displays a load shedding alert code (E600) and an alert appears on the display of the iComfort

thermostat. The customer receives email notifica

Wi-Fi tions when the alert occurs, if the option to receive notifications is selected.

Utility Load-Shedding Mode DEACTIVATED (Normal Equipment Operation) – When load shedding

mode is not required, the contacts in the utility load control receiver are closed. This provides 24VAC to the coil of the field-provided relay (catalog # 69J79).The relay contacts

OPEN (terminal 7 to terminal 2) removing 24VAC from the L terminal on the outdoor control. This deactivates the

load-shedding mode in the outdoor control. The outdoor unit returns to normal operation and alert code clears once load-shedding mode is deactivated.

For more information, see the Load-Shedding Feature Wir ing Diagram on page 47.

SIZE CIRCUIT AND INSTALL DISCONNECT SWITCH

REFER TO THE UNIT NAMEPLATE FOR MINIMUM CIRCUIT AMPACITY, AND MAXIMUM FUSE OR CIRCUIT BREAKER (HACR PER NEC). INSTALL POWER WIRING AND PROPERLY SIZED DISCONNECT SWITCH.

MAIN FUSE BOX/ BREAKER PANEL

DISCONNECT

SWITCH

NOTE - UNITS ARE APPROVED FOR USE ONLY WITH COPPER CONDUCTORS. GROUND UNIT AT DISCONNECT SWITCH OR TO AN EARTH GROUND.

Figure 12. Electrical Installation

INSTALL THERMOSTAT

INSTALL ROOM THERMOSTAT (ORDERED SEPARATELY) ON AN INSIDE WALL, APPROXIMATELY IN THE CENTER OF THE

CONDITIONED AREA AND 5 FEET (1.5M) FROM THE FLOOR. IT SHOULD NOT BE INSTALLED ON AN OUTSIDE WALL OR WHERE IT CAN BE AFFECTED BY SUNLIGHT OR DRAFTS.

THERMOSTAT

5 FEET

(1.5M)

NOTE - 24VAC, CLASS II CIRCUIT CONNECTIONS ARE MADE IN THE CON TROL BOX.

XC20

Page 25

ROUTE CONTROL WIRES

Maximum length of wiring (18 gauge) for all connections on the RSBus is 1500 feet (457 meters). Wires should be color-coded, with

a temperature rating of 95 field-provided field-installed grommet installed in electrical inlet.

The iComfort Wi-Fi iComfort® control and four wires between the outdoor unit and the furnace/air handler iComfort® control. When a thermostat cable with more than four wires is used, the extra wires must be properly connected to avoid electrical noise (see below).

Use a wire nut to bundle the four unused wires at each end of the cable. Each bundle should also include an additional wire that should be connected on each end to the C terminal as shown in the figure below.

F (35ºC) minimum, and solid-core (Class II Rated Wiring). All low voltage wiring must enter unit through

or iComf ort® S30 thermostats require four thermostat wires between the thermostat and the furnace / air handler

OUTDOOR UNIT

PROVIDED RAST

6-PIN CONNECTOR

CONNECTS TO

RAST 6-PIN

CONNECTOR

ROUTE CONTROL

WIRING THROUGH

GROMMET AND

SECURE WITH

CABLE TIE

Single Wire To

C Terminal

Unused Wires

GROMMET AND CABLE TIE.

INDOOR CONTROL

Indoor Control

CONNECT CONDUIT TO CUTOUT AND ROUTE HIGH VOLTAGE WIRING

USE WATERTIGHT CONDUIT FOR HIGH VOLTAGE

Single Wire To C Terminal

Unused Wires

ROUTE HIGH VOLTAGE AND GROUND WIRES

Any excess high voltage field wiring should be trimmed and secured away from any low voltage field wiring. To facilitate a conduit, a

cutout is located on the bottom of the control box. Connect conduit to the control box using a proper conduit fitting.

Figure 13. Electrical Installation (Continued)

XC20

Page 26

CAUTION

Electrostatic discharge can affect electronic components. Take precautions

ELECTROSTATIC DISCHARGE

(ESD)

Precautions and Procedures

STEP 3 -- ELECTRICAL (Continued) -- Outdoor Control Unit

during unit installation and service to protect the unit's electronic controls. Precautions will help to avoid control exposure to electrostatic discharge by putting the unit, the control and the technician at the same electrostatic potential. Neutralize electrostatic charge by touching hand and all tools on an unpainted unit surface before performing any service procedure.

NOTE - The green LED located on the outdoor control flashes when communication occurs between the outdoor control and either the thermostat or the inverter.

XC20

WHEN THE UNIT IS IN PUMP-DOWN MODE,  IS SHOWN ON

TO ACTIVATE PUMP-DOWN MODE, REFER TO PUMP-DOWN

Figure 14. Outdoor Unit Control

7-SEGMENT

PUSH

BUTTON

THE 7-SEGMENT DISPLAY.

CYCLE SEQUENCE ON PAGE 39.

DISPLAY

Page 27

TABLE 5

Outdoor Control Terminal Designations and Input /Outputs (see figure 14 for terminal locations)

Designator Description Input Output Common

O OUT

LO PS Low pressure switch N/A 5ma @18VAC N/A LO PS Low pressure switch sensing connection 5ma @18VAC N/A N/A Hi PS High pressure switch N/A 24VAC nominal N/A Hi PS High pressure switch sensing connection 24VAC nominal N/A N/A

TP Top cap thermostat switch sensing connection 24VAC nominal N/A N/A

Cntctr

Cntctr Contactor common N/A 24VAC common

Fan PWM PWM fan output N/A

COM PWM fan common connection N/A N/A

Fan Park

Unused on XC20, for heat pump applications only.

Top cap thermostat switch (in series with the HI PS)

Control (inverter power) contactor switched out put (in series with the HI PS and TC)

PWM fan parking spot for unused terminal, not connected.

N/A

N/A N/A 24VAC common

N/A 24VAC nominal N/A

N/A

N/A N/A N/A

Switched 24VAC nominal

Switched 24VAC Nominal

1097% duty cycle, 1923 VDC peak

N/A

Fan PWM com mon

P2 Terminal Designations

Y1 Y1 emergency input

C 24VAC nominal power return. N/A N/A 24VAC common i Low data line. Data Data N/A i+ High data line. Data Data N/A

R 24VAC nominal power input.

DF OEM test N/A N/A N/A

TOUT

TST

Unused on XC20, for heat pump applications only.

26Vdc transistor output to Lennox factory OEM tester

OEM test pin. In each terminal box:

P2  Terminal 1  TEST P2  Terminal 2  TOUT P2  Terminal 3  DF P2  Terminal 4  R

24VAC nominal from ther mostat and loaded to draw 17ma at 30VAC

24VAC nominal board main power input.

N/A N/A N/A

24VAC nominal 17ma @ 30VAC

N/A N/A

XC20

Page 28

Table 5 continued.

Outdoor Control Terminal Designations and Input /Outputs

WARNING - Electric Shock Hazard. Can cause injury or death. Unit must be grounded in accordance with national and

local codes. The 4 pins in P6 have the potential of transferring up to 250 volts to the unit cabinet ground.

Designator Description Input Output Common

Outdoor control

communication

transmit pin.

Inverter common.

P6 - Pin 1 Tx

P6 - Pin 2

Inverter

Common

Transmit data to inverter, connects to Rx of inverter.

Inverter common

NOTE - This is a signal reference point and not an earth ground.

Outdoor control

communication

receive pin.

P6 - Pin 3 Rx

Receive data from the inverter. Connects to Tx of inverter.

P6 - Pin 4 Inv 5V Inverter 5VDC volts. Inverter 5VDC volts

LIQ

Liquid line temperature sensor sup ply.

N/A N/A N/A

• Pin 1 to pin 2 should read 4.5 to 5.5 VDC when not communicating.

• Pin 3 to pin 2 should read 4.5 to 5.5 VDC when not communicating.

• Pin 4 to pin 2 should read 4.5 to 5.5 VDC.

NOTE - Communication signals switch off and on rapidly. This may cause volt meter readings to fluctuate. This is normal. Communication signals will switch between this 5V and common (Pin 2).

LIQ Liquid line temperature sensor return. N/A N/A N/A

AMB

COIL

Pump Down

Outdoor ambient temperature sensor supply.

Outdoor ambient temperature sensor return.

Outdoor coil temperature sensor sup ply.

Outdoor coil temperature sensor re turn.

To initiate pump-down function, place jumper in the ON position. (See PUMP-DOWN MODE OPERATION on page 37.)

1. Place the jumper in the ON position to

activate pump-down mode.

2. Place the jumper in the OFF position to

deactivate pump-down mode.

NOTE -If the pump-down jumper is in the ON position during power-up, it is ignored.

NOTE - The outdoor control stays in pump-down mode for five minutes, after which the outdoor control initiates a compressor shutdown sequence.

N/A N/A N/A

PUMP

DOWN

OFF

PUMP

DOWN

OFF

24VAC input to L en

L Load-shedding input

ergizes load shed

N/A N/A

ding feature.

Load-shedding input reference. Refer

to wiring of load-shedding terminals

N/A N/A

located on page 47.

24VAC

common

XC20

Page 29

Servicing Units Delivered Void of Charge

If the outdoor unit is void of refrigerant, clean the system us ing the procedure described below.

1. Leak test the system using the procedure outlined on page 22.

2. Evacuate the system using procedure outlined on page 23.

3. Use nitrogen to break the vacuum and install a new fil ter drier in the system.

4. Evacuate the system again using procedure outlined on page 23.

5. Weigh in refrigerant using procedure outlined in figure

56.

6. Monitor the system to determine the amount of mois ture remaining in the oil. It may be necessary to replace the filter drier several times to achieve the required dry ness level. If system dryness is not verified, the

compressor will fail in the future.

Unit Start-Up

IMPORTANT

1. Rotate fan to check for binding.

2. Inspect all factory- and field-installed wiring for loose connections.

3. After evacuation is complete, open both the liquid and vapor line service valves to release the refrigerant charge contained in outdoor unit into the system.

4. Replace the stem caps and tighten to the value listed in table 1.

5. Check voltage supply at the disconnect switch. The voltage must be within the range listed on the unit's nameplate. If not, do not start the equipment until you have consulted with the power company and the voltage condition has been corrected.

6. Set the thermostat for a cooling demand. Turn on power to the indoor unit and close the outdoor unit dis connect switch to start the unit.

7. Recheck voltage while the unit is running. Power must be within range shown on the nameplate.

If unit is equipped with a crankcase heater, it should be energized 24 hours before unit start-up to prevent compressor damage as a result of slugging.

8. Check system for sufficient refrigerant by using the procedures listed in the System Refrigerant section on

page 75.

XC20

Page 30

III. SYSTEM OPERATION AND SERVICE

7-Segment Alert and System Status Codes

Alert codes are displayed using the 7-segment display loc ated on the outdoor control.

NOTE - System fault and lockout codes take precedence over system status codes (cooling, heating operating per centages or defrost/dehumidification).

The 7-segment will display an abnormal condition (error code) when detected in the system. A list of the codes are shown in table 6.

RESETTING ALERT CODES

Alert codes can be reset manually or automatically:

1. Manual Reset

Manual reset can be achieved by one of the following methods:

Table 6. Outdoor Control 7-Segment Display Alert Codes and Inverter LED Flash Codes

NOTE - System fault and lockout codes take precedence over system status codes (cooling, heating operating percentages or defrost/dehumidification). Only the latest active fault or lockout codes are displayed (if present). If no fault or lockout codes are active, then system status codes are displayed. Alert codes are also displayed on the iComfort Wi-Fi

Inverter LED Flash

Alert

Codes

N/A N/A ON OFF N/A XC/XP 20-024 and -036 only: Indicates inverter is operating normally.

N/A N/A ON ON N/A XC/XP 20-048 and -060 only: Indicates inverter is operating normally.

N/A N/A OFF OFF N/A Indicates inverter is NOT energized.

E 105 N/A N/A N/A Moderate

E 120 N/A N/A N/A Moderate

E 124 N/A N/A N/A Critical

E 125 N/A N/A N/A Critical

E 131 N/A N/A N/A Critical

E 132 N/A N/A N/A Critical Internal software error. Replace outdoor control.

E 180 N/A N/A N/A Critical

Inverter

Code

Code (number of

flashes)

Red LED Green LED

XC20

or iComfort

Priority Alarm Description Possible Causes and Clearing Alarm

S30 thermostat.

The outdoor control has lost communication with either the thermostat or in door unit.

There is a delay in the out door unit responding to the system.

The iComfort WiFi® or iComfort has lost communication with the outdoor unit for more than 3 minutes.

There is a hardware prob lem with the outdoor con trol.

The outdoor unit control parameters are corrupted.

The outdoor unit ambient temperature sensor has malfunctioned. As a result the outdoor unit control will not perform low ambient cooling.

S30 thermostat

• Disconnecting R wire from the outdoor control R

terminal.

• Turning the indoor unit off and back on again

After power up, all currently displayed codes are cleared.

2. Automatic Reset

After an alert is detected, the outdoor control continues to monitor the unit's system and compressor opera tions. When/if conditions return to normal, the alert code is turned off automatically.

NOTE - Error codes can be recalled by following in formation shown in the table on page 37.

Equipment is unable to communicate. Indicates nu merous message errors. In most cases errors are re lated to electrical noise. Make sure high voltage power is separated from RSBus. Check for miswired and/or loose connections between the stat, indoor unit and outdoor unit. Check for a high voltage source of noise close to the system. Fault clears after communication is restored.

Typically, this alarm/code does not cause any issues and clears on its own. The alarm/code is usually caused by a delay in the outdoor unit responding to the thermostat. Check all wiring connections. Cleared after unresponsive device responds to any inquiry.

Equipment lost communication with the thermostat. Check the wiring connections and resistance, then cycle the system power. This alarm stops all associ ated HVAC operations and waits for a signal from the non-communicating unit. The alarm / fault clears after communication is reestablished.

There is a control hardware problem. Replace the out door control if the problem prevents operation and is persistent. The alarm / fault is cleared 300 seconds after the fault recovers.

Reconfigure the system. Replace the control if heating or cooling is not available.

Valid temperature reading is lost during normal opera tion and after outdoor control recognized sensors. Compare outdoor sensor resistance to temperature/ resistance charts in unit installation instructions. Re place sensor pack if necessary. At the beginning of (any) configuration, furnace or airhandler control de tects the presence of the sensor(s). If detected (reading in range), appropriate feature is shown in the iComfort

WiFi

or iComfort® S30 thermostat About screen. The alarm / fault clears upon configuration, or when normal values are sensed.

Page 31

Table 6. Outdoor Control 7-Segment Display Alert Codes and Inverter LED Flash Codes

Inverter LED Flash

Alert

Codes

Inverter

Code

Code (number of

flashes)

Red LED Green LED

E 345 N/A N/A N/A Critical

E 409 N/A N/A N/A Moderate

E 410 N/A N/A N/A Moderate

E 411 N/A N/A N/A Critical

E 412 N/A N/A N/A Moderate

E 413 N/A N/A N/A Critical

E 416 N/A N/A N/A

thermostat.

Priority Alarm Description Possible Causes and Clearing Alarm

Issue: Broken R50 will make the control board think re

versing valve output is always off regardless of state of re lay. (Supplier issue - We have found our functional test fix

Heat Pump or Air Conditioner Alert Code - The "O" relay on the outdoor board has failed. Either the pilot relay contacts did not close, the relay coil did not energize or the circuit that confirms this operational sequence is not sensing properly.

ture can bend over MOV2 and crush it into R50.There are cut-outs in the plate of the fixture to let the two relays pass through as the plate with pogo pins is moved to the board to make contact with the terminals. There is a pocket milled out in the plate to let MOV2 pass, but if MOV2 is not straight up, it could catch the plate outside the pocket and be bent down to the board. Lennox is enlarging the cutouts in the plate so MOV2 will clear the fixture. Corrective action completed on August 29,2013.

Corrective Actions: Short term fix: Converted the sys tem back to a 24 volt system to get unit operating. Long term: Replace outdoor control.

Secondary voltage is below 18VAC. After 10 minutes, op

Outdoor control secondary voltage is 18VAC or less.

eration is discontinued. Check the indoor line voltage and transformer output voltage. The alarm clears after the voltage is higher than 20VAC for 2 seconds or after a power reset.

Unit pressure is below the lower limit. The system is shut

down. The low pressure switch closes above 90PSIG and The outdoor unit cycled off due to low pressure switch opening.

opens below 40PSIG. Confirm that the system is properly

charged with refrigerant. Check TXV, indoor unit blower

motor, dirty filters or clogged refrigerant filter. Confirm that

the evaporator coil is clean. The alarm clears after the

pressure switch opens or after a power reset.

Low pressure switch error count reached 5 strikes. The

The low pressure switch has opened 5 times within one hour. As a result, the outdoor unit is locked out

low pressure switch opens at 40PSIG and resets at

90PSIG. Confirm that the system is properly charged with

refrigerant. Check for clogged TXV, blockage to indoor

unit blower motor, dirty filters or clogged refrigerant filter.

Confirm that the evaporator coil is clean. The alarm clears

after a power reset.

Unit pressure is above the upper limit. System is shut

down. The high pressure switch opens at 590PSIG and

closes at 418PSIG. Confirm that the system is properly

The outdoor unit high pres sure switch has opened.

charged with refrigerant. Check for clogged TXV, block

age to indoor unit blower motor, clogged refrigerant filter.

Confirm that the outdoor unit is clean. The alarm clears

after the pressure switch closes or a power reset.

For heating, indoor CFM may be set too low. For zoning

system, zone CFM may be set too low.

Open high pressure switch error count reached 5 strikes.

System is shut down. The high pressure switch for

HFC410A opens at 590PSIG and closes at 418PSIG.

The high pressure switch has opened 5 times within one hour. As a result, the outdoor unit is locked out

Confirm that the system is properly charged with refriger

ant. Check condenser fan motor, for clogged TXV, for

blockage to indoor unit blower motor, for stuck reversing

valve or clogged refrigerant filter. Confirm that the out

door unit is clean. The alarm clears after a power reset.

For heating, indoor CFM may be set too low. For zoning

system, zone CFM may be set too low.

Coil sensor being detected open or shorted, or temperat

ure is out of coil sensor range. Outdoor unit control will not

Moderate / Critical

The outdoor coil sensor has malfunctioned. As a result the outdoor unit control will not perform defrost.

perform demand or time/temperature defrost operation.

System is still able heat and cool. Check the resistance of

the coil sensor and compare to temperature resistance

chart. Replace coil sensor if needed. The alarm clears

when outdoor unit control detects proper coil sensor

readings or after a power reset.

XC20

Page 32

Table 6. Outdoor Control 7-Segment Display Alert Codes and Inverter LED Flash Codes

Inverter LED Flash

Alert

Codes

Inverter

Code

Code (number of

flashes)

Red LED Green LED

E 422 N/A N/A N/A Moderate

E 423 40 4 flashes OFF

E 424 N/A N/A N/A Moderate

E 425 N/A N/A N/A Minor

E 426 N/A N/A N/A Critical Excessive inverter alarms

E 427 21 2 flashes 1 flash

E 428 22 2 flashes 2 flashes

E 429 23 2 flashes 3 flashes

thermostat.

Priority Alarm Description Possible Causes and Clearing Alarm

Issue: One of the wires from the top cap switch had pulled

Compressor top cap switch exceeding thermal limit.

off one of the TP terminals on the outdoor control board. Corrective Action: Reconnected wire onto top cap ter

minal.

Moderate / Critical

The inverter has detected a circuit problem.

Control locks out after 10 strikes within an hour. To clear, disconnect power to outdoor unit and restart.

In normal operation, after outdoor control recognizes sensors, the alarm is sent if valid temperature reading is lost. Compare liquid line sensor resistance to temperat

ure/resistance charts in unit installation instructions. Re The liquid line temperature sensor has malfunctioned.

place sensor pack if necessary. At the beginning of (any)

configuration, furnace or airhandler control detects the

presence of the sensor(s). If detected (reading in range),

appropriate feature is shown in the iComfort WiFi

mostat About screen. The alarm / fault clears upon con

figuration, or when normal values are sensed.

Outdoor control has in creased minimum com pressor speed to allow for proper oil return due to low ambient temperature. NOTE - Minimum speed adjustments begin at 45°F and increase to

Outdoor ambient temperature is below system limit. Con

trol attempts to run at lowest allowed compressor speed

to allow for proper oil return. Automatically clears when

outdoor ambient temperature rises above limit for more

than 5 minutes.

100% minimum at 17°F.

After ten faults within one hour, control is locked out, indic

ating poor system operation. Review history of alarms to

resolve system setup. Check condenser fan motor, TXV,

indoor unit blower motor, over-charge, undercharge, or

clogged refrigerant filter.

To clear error, disconnect power to outdoor unit and re

start. Inverter alarms 12 to 14 and 53 do not count toward

this lock out condition.

The inverter has detected a DC peak fault condition. If condition (55A or higher) is detec

Moderate / Critical

ted, outdoor unit compressor and fan stop. Anti-short cycle is initiated. If peak current (55A or higher) occurs 10 times within an hour, system is locked out. Indicates high pres sure, condenser fan failure, locked compressor rotor or overcharge. To clear, disconnect power to outdoor unit and restart.

If condition is detected, is detected, outdoor unit com

pressor and fan stop. Antishort cycle is initiated. If condi

tion occurs 5 times within an hour, system is locked out.

Indicates high pressure, condenser fan failure or over

charge.

Moderate / Critical

The inverter has detected a high main input current con

dition

To clear, disconnect power to outdoor unit and restart.

Issues:

(1) If DC link power in inverter does not rise above 180

VDC for 2- and 3-ton models, 250 VDC for 4- and 5-ton

models, within 30 seconds, the outdoor control will dis

play a moderate code.

(2) Capacitors on inverter do not properly charge.

Corrective Actions:

(1) check for proper main power to outdoor unit and for

any loose electrical connections.

(2) Outdoor control boards with part # 103686-03 have

software update to delay the de-energizing of the revers

ing valve by four seconds when coming out of defrost.

Moderate / Critical

On a call for compressor op eration, if DC link power in in verter does not rise above 180 VDC for 2 and 3 ton mod els, 250 VDC for 4 and 5 ton models, within 30 seconds, the control will display a mod erate code. If condition is de tected, outdoor unit will stop (Compressor and fan). Antishort cycles is initiated. If condition occurs 10 times within a 60 minute rolling time period, system will lock out and display a critical code.

ther

XC20

Page 33

Table 6. Outdoor Control 7-Segment Display Alert Codes and Inverter LED Flash Codes

Inverter LED Flash

Alert

Codes

Inverter

Code

Code (number of

flashes)

Red LED Green LED

E 430 26 2 flashes 6 flashes

E 431 27 2 flashes 7 flashes

E 432 28 2 flashes 8 flashes

E 433 29 2 flashes 9 flashes

E 434 53 5 flashes 3 flashes

E 435 60 6 flashes OFF

thermostat.

Priority Alarm Description Possible Causes and Clearing Alarm

If condition is detected, outdoor unit compressor and fan stop. Antishort cycle is initiated. If condition occurs 10 times within an hour, system is locked out.

Moderate / Critical

Compressor start failure.

Indicates poor connection at compressor harness, im proper winding resistance, locked compressor rotor, or flooded compressor.

To clear, disconnect power to outdoor unit and restart.

Issues:

(1) Indicates power interruption, brownout, poor electrical connection or loose inverter input wire.

(2) System testing was set up and code was generated when the reversing valve is de-energized coming out of defrost (code appears with or without 30 compressor delay).

Corrective Actions:

(1) Check for proper main power to outdoor unit and for any loose electrical connections.

(2) Outdoor control boards with part # 103686-03 have software update to delay the de-energizing of the revers ing valve by four seconds when coming out of defrost.

Moderate / Critical

Error occurs when PFC de tects an over-current condi tion of 100A, the control will display a moderate code. If condition is detected, out door unit will stop (Com pressor and fan). Anti-short cycle is initiated. Inverter is unavailable to communicate with the outdoor control for 3 minutes. If condition occurs 10 times within a 60 minute rolling time period, system will lock out and display a crit ical code.

Error occurs when the DC link capacitor voltage is greater

Moderate

/ Critical

The inverter has detected a DC link high voltage condi tion.

than 480VDC. If condition is detected, outdoor unit com pressor and fan stop. Antishort cycle is initiated. If condi tion occurs 10 times within an hour, system is locked out. System stops. To clear, disconnect power to outdoor unit and restart.

Error occurs when compressor peak phase current is greater than 28A. Inverter issues code 14 first and slows

Moderate

/ Critical

The inverter has detected a compressor over-current condition

down to try to reduce the current. If the current remains high, outdoor unit compressor and fan stop. Antishort cycle is initiated. If condition occurs five times within an hour, system is locked out. To clear disconnect power to outdoor unit and restart.

Outdoor control has lost communications with the

Issues:

(1) Loose electrical connections.

(2) Interruption of main power to inverter.

Corrective Actions:

(1) Check all electrical connections.

(2) Check for proper main power to inverter.

Moderate / Critical

inverter for greater than 3 minutes. Outdoor control will stop all compressor de mands, recycle power to the inverter by de-energiz ing the contactor for 2 minutes. If this occurs 3 time in one thermostat call, the outdoor unit will locked out and display a critical code.

When this error occurs, the outdoor control cycles power

Moderate / Critical

Inverter internal error.

to the inverter by opening the contactor for two minutes. Check that the EEPROM is properly seated. After power is cycled to the inverter 3 times, the outdoor unit is locked out

XC20

Page 34

Table 6. Outdoor Control 7-Segment Display Alert Codes and Inverter LED Flash Codes

Inverter LED Flash

Alert

Codes

E 436 62 6 flashes 2 flashes

E 437 65 6 flashes 5 flashes

E 438 73 7 flashes 3 flashes

E 439 12 1 flash 2 flashes Moderate

E 440 13 1 flash 3 flashes Moderate

Inverter

Code

Code (number of

flashes)

Red LED Green LED

thermostat.

Priority Alarm Description Possible Causes and Clearing Alarm

Inverter heat sink temperat ure exceeded limit. Occurs

Moderate / Critical

when the heat sink temper ature exceeds the inverter limit. Inverter issues code 13 first, then slows down to allow the heat sink to cool. If temperature remains high, outdoor unit stops (com pressor and fan). Anti-short cycle is initiated. If condition occurs 5 times within an hour, system is locked out. To clear, disconnect power to outdoor unit and restart.

Heat sink temperature sensor fault has occurred (temperature less than 4ºF or greater than 264ºF after 10 minutes of operation)

The inverter has detected a PFC over current condition. This would be caused by a high load condition, high pressure, or outdoor fan fail ure.Outdoor control will dis play the code when the in verter has the error. After 3 minutes, the inverter will re set and the compressor will turn on again. If it happens 10 times within a 60 minute rolling time period, the OD control will lock out opera tion of the outdoor unit and display a critical code.

Compressor slowdown due to high input current.

Heat sink temperature is approaching limit. The compressor speed auto matically slows to reduce heat sink temperature. The control sets indoor CFM and outdoor RPM to values according to demand per centage rather than the ac tual Hz. Alarm is automatic ally cleared.

Issue: Feedback from supplier tear down of inverter in

dicates that the screws that hold the inverter to the invert

er board were loose causing poor contact between these

two components.

Corrective Action: Tighten screws that hold the heat

sink to the inverter control board.

NOTE: Wait five minutes to all capacitor to discharge be

fore checking screws.

Occurs when the temperature sensor detects a temperat

ure less than 0.4ºF or greater than 264ºF after 10 minutes

of operation. If condition is detected, outdoor unit will stop

(compressor and fan). Antishort cycle is initiated. If con

dition occurs 5 times within an hour, system will lock out.

To clear disconnect power to outdoor unit and restart. If

problem persists, replace inverter.

Issue: Possible issue is system running at high pres

sures. Check for high pressure trips or other alert codes in

room thermostat and outdoor control.

Input current is approaching a high limit. Compressor

speed automatically slows. The control continues send

ing the inverter speed demanded by the thermostat. The

control sets indoor CFM and outdoor RPM to values ac

cording to demand percentage rather than the actual Hz.

Alarm is automatically cleared.

Issue: Feedback from supplier tear down of inverter in

dicates that the screws that hold the inverter to the invert

er board were loose causing poor contact between these

two components.

Corrective action: Tighten screws that hold the heat sink

to the inverter control board.

NOTE: Wait 5 minutes to all capacitor to discharge before

checking screws.

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Table 6. Outdoor Control 7-Segment Display Alert Codes and Inverter LED Flash Codes

Inverter LED Flash

Alert

Codes

E 441 14 1 flash 4 flashes Moderate

E 442 N/A N/A N/A Critical

E 443 N/A N/A N/A Critical

E 600 N/A N/A N/A Critical

E 601 N/A N/A N/A Critical

Inverter

Code

Code (number of

flashes)

Red LED Green LED

thermostat.

Priority Alarm Description Possible Causes and Clearing Alarm

Compressor slowdown due to high compressor current. Compressor current is ap proaching limit. The com pressor speed automatic ally slows. The control sets indoor CFM and outdoor RPM to values according to demand percentage rather than the actual Hz. Alarm is automatically cleared..

The top cap switch has opened five times within one hour. As a result, the outdoor unit is locked out

Incorrect appliance unit size code selected.

Compressor has been cycled OFF on utility load shedding.

Outdoor unit has been cycled OFF on low temper ature protection.

Issue: Possible issue is system running at high pres sures. Check for high pressure trips or other alert codes in room thermostat and outdoor control.

When compressor thermal protection sensor opens five times within one hour, outdoor stops working. To clear, disconnect power to outdoor unit and restart.

Check for proper configuring of unit size codes for out door unit in configuration guide or in installation instruc tions. If replacing inverter, verify inverter model matches unit size. The alarm/fault clears after the correct match is detected following a reset. Remove the thermostat from the system while applying power and reprogramming.

Load shedding function: Provides a method for a local utility company to limit the maximum power level usage of the outdoor unit. The feature is activated by applying 24 volts AC power to the L and C terminals on the outdoor control.

Low temperature protection: Outdoor unit will not operate when the outdoor temperature is at or below 4°F (20°C). If the unit is operating and the outdoor temper ature drops below 4°F (20°C), the unit continues to op erate until the room thermostat is satisfied or the outdoor temperature drops to 15°F (26°C). Outdoor unit ambi ent sensor provides temperature readings.

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Page 36

POWER-UP / RESET:

7-SEGMENT POWER-UP DISPLAY STRING

FIRMWARE VERSION: During initial power-up or reset, the first item displayed is the outdoor control firmware version. Example to the right shows firmware version 2.3.

UNIT TYPE: The next item displayed is the self discovery unit type. AC = air conditioner and HP = heat pump. If the unit type cannot be determined, three bars appear.

UNIT NOMINAL CAPACITY: The next item to be displayed is the self-discovery unit nominal capacity. Valid capacities are 24 for 2-ton, 36 for 3-ton, 48 for 4-ton and 60 for 5-ton units. If the unit type cannot be determined, three bars ap pear.

UNIT CODE: The next item to be displayed is the self discov ery unit code. (may be a single character or two characters). If the unit code cannot be determined, three bars appear.

UNIT CODE

 







UNIT TYPE, SIZE AND MODEL

NOT PROGRAMMED

2-TON HEAT PUMP, XP20-024



3-TON HEAT PUMP, XP20-036



4-TON HEAT PUMP, XP20-048

5-TON HEAT PUMP, XP20-060





THROUGH



(These are just examples of firmware version, unit type,



FIRMWARE

VERSION

unit nominal capacity and unit codes.)

7-SEGMENT POWER-UP DISPLAY STRING EXAMPLE





UNIT

TYPE











UNIT

CAPACITY



UNIT

CODE



IDLE MODE















2-TON AIR CONDITIONER, XC20-024

3-TON AIR CONDITIONER, XC20-036

4-TON AIR CONDITIONER, XC20-048

5-TON AIR CONDITIONER, XC20-060

Figure 15. Outdoor Control 7-Segment Unit Status Displays

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Page 37

Table 7. Outdoor Control 7-Segment Unit Status Displays

Description Example of Display

Idle Mode: Decimal point flashes at 1 Hz.

Soft Disable Mode: Top and bottom horizontal line and decimal

point flash at 1 Hz. If indoor or outdoor control displays Soft Disable code:

1) Confirm proper wiring between all devices (thermostat, indoor and outdoor).

2) Cycle power to the control that is displaying the Soft Disable code.

3) Put the room thermostat through Setup.

4) Go to Setup/System Devices/Thermostat/Edit/push Reset.

5) Go to Setup/System Devices/Thermostat/Edit/push Reset All. If the room thermostat detects a new device or a device that is not communicating, it sends a Soft Disable. When this occurs, Alarm 10 is activated and the room thermostat sends a Soft Dis able command to the offending device on the bus (outdoor con trol, IFC, AHC, EIM or Damper Control Module).

O.E.M. Test Mode

Anti-Short Cycle Delay

Cooling Cycle: Shows current percentage of maximum cooling

capacity. Example to the right indicates a cooling demand of 50 percent and a outdoor fan speed of 700 RPM.

Idle Mode: Decimal point flashes at 1 Hz (0.5 second on, 0.5 second off). Display OFF.

Soft Disable Mode: Top and bottom horizontal line and decimal point flash at 1 Hz (0.5 second on, 0.5 second off).

The iComfort control in Soft Disable Mode is indicated by the following:

• On AHC, IFC and outdoor controls, Soft Disable Mode is indicated by flashing double horizontal lines on the 7-segment display.

• On the Damper Control Module and EIM, the green LED will blink 3 sec onds on and 1 second off.

All segments flashing at 2 Hz (unless error is detected). NOTE - Control

should be replaced.

The middle line flashes at 1 Hz for 2 seconds, followed by a 2-second dis play of the number of minutes left on the timer (value is rounded up: 2 min. 1 sec. is displayed as 3). If activated, the anti-short cycle delay time remain ing is displayed (default is 300 sec./5 min.).

The demand percentage is displayed first, followed by a pause, then the outdoor fan speed and the ambient temperature.

   pause     pause   

Diagnostic recall: Shows the last 10 stored diagnostic error

codes.

Fault memory clears

Active error in outdoor control Idle mode: Show all active

error(s) codes.

Active error in run mode: Show current status and all active error(s) codes.

Outdoor Ambient Temperature (OAT): Any time OAT is within operating range, value is displayed if unit is in diagnostic and non-diagnostic modes.

Outdoor Coil Temperature (OCT): Any time OCT is sensed in operating range, value is displayed if unit is in diagnostic mode or manually enabled for non-diagnostic modes.

Liquid Line Temperature (LIQ): Any time LIQ is sensed in oper ating range, value is displayed if unit is in diagnostic mode or manually enabled for non-diagnostic modes.

Pump-Down Mode: While the unit is in pump-down mode,   is displayed repeatedly. Errors are shown if they exist.

If first error is    , second     pause     pause

   

Next codes (up to 10) are shown using same method.

If there are no error codes stored:  pause    . After the fault memory is cleared, the following string flashes every 0.5 seconds:

    pause

Following display string is repeated if Error E 125 and E 201 are present:

    pause    

Following display string is repeated if Error E 440 is present while outdoor fan speed at 700RPM:

    pause    

Following display string is repeated if cooling is active with outdoor fan speed set at 650 RPM and OAT is 104

   pause     pause     pause

Following display string is repeated if heat is active with outdoor fan speed set at 550 RPM and OCT is 25

   pause     pause    pause

Following display string is repeated if cooling is active with outdoor fan speed set at 650 RPM and LIQ is 105

   pause     pause     pause

Following display string is repeated:

  pause  

 

pause     pause   pause    

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Page 38

PUSH−BUTTON OPERATION

Allows field access to Diagnostic, Fan, Defrost and Error Code Re call modes.

Outdoor control must be in IDLE mode (no heating or cooling operation).

NOTE - See table 6 for explanation of codes.

To enter mode options, push and hold button next to 7seg ment display until DASH symbol appears. Immediately re lease the button. Once dash starts flashing, proceed to next step.

Push and hold button until the selection stops flashing, then release button. The 7 seg ment display shows the selected mode and the control performs the selected function.

Push and hold button until mode selection displays on the 7seg

ment display (, ,    ,  or ). Immediately release the button,

proceed to next step.



Figure 16. Push-Button Operation

Unit Selection Code for Outdoor Control

If the single-character display shows three (3) horizontal lines, the unit selection code needs to be programmed. Press and hold the button until the   menu option is displayed, release button. The singlecharacter display displays the selected mode per example in figure 15 on page 36. When the desired unit selection code appears, press and hold the button until it stops flashing, then release.

Unit Code Unit Type Unit Model

    



 

2-ton heat pump XP20-024

3-ton heat pump XP20-036

4-ton heat pump XP20-048

5-ton heat pump XP20-060

2-ton air conditioner XC20-024

3-ton air conditioner XC20-036

4-ton air conditioner XC20-048

5-ton air conditioner XC20-060

XC20

Page 39

Idle mode — System is energized with no demand — Decimal flashes at 1 Hertz > 0.5 second ON, 0.5 second OFF.

Display Symbol or Character

Displayed

during start-up

or power

recycling.

Display Fan Test and Display String Option

Display string shows outdoor control firmware version    > pause>   or   unit >pause>unit capacity in BTUs>pause >unit code. If 3 horizontal bars are displayed during any sequence of this display string, it indicates that the specific parameter is not configured.

Idle mode — decimal flashes at 1 Hertz > 0.5 second ON, 0.5 second OFF

 or  Indicates either cooling () or heating () mode and demand percentage.

 





Error Code Recall Mode (NOTE - control must be in idle mode)



—



Code displays when system is in defrost mode. To enter defrost mode, unit must be running in heating mode, outdoor ambient must be below 65F and outdoor coil temperature must be below defrost termination temperature.

Control must be in Idle mode: To enter fan test option -  mode, push and hold button until solid – appears, release button. Display begins flashing. Within 10 seconds, push and

Indicates outdoor fan RPM speed.

 in the display string represents the

ambient temperature in F at the sensor on the outdoor unit. In display configuration mode, it also repres ents the option for enabling both coil and liquid line temperature on the 7-segment display string.

To enter error code recall mode, push and hold button until solid  appears, then release button. Control displays up to 10 error codes stored in memory. If     is displayed, there are no stored error codes.

To exit error code recall mode, push and hold button until solid three horizontal bars appear, then release button. Note - Error codes are not

cleared.

To clear error codes stored in memory, continue to hold button while the 3 horizontal bars are displayed. Release button when solid  is displayed.

Push and hold for one (1) second, release button. 7-Segment displays     and exits error recall mode.

hold button until required symbol in 10 seconds, push and hold button until display stops flashing, release button. Control outputs DC voltage on PWM and COM terminals. Outdoor fan cycles ON for 10 minutes at 490 RPM. To exit test – Push and hold button until three horizontal bars display. Release button, outdoor fan cycles OFF. Control can be in Idle or demand mode: To enter display configuration option -  mode, push and hold button until solid – appears, release button. Display begins flashing. Within 10 sec onds, push and hold button until required symbol flashing. Within 10 seconds, push and hold button until display stops flashing, release button. Display shows error () code(s), ambient (), outdoor coil () and liquid () temperatures in Fahrenheit.

NOTE - If button is not pushed in the 10-second time period, the control exits the test mode. If this occurs, test mode must be repeated.

 displays, release button. Display begins flashing. With

 displays, release button. Display begins

FIELD TEST MODE OPERATION

The field test mode allows the unit to be put into diagnostic mode and allows the installer to perform multiple tests on the control / unit.

Diagnostic Mode

Diagnostic mode is only available when the system is idle or during an active / suspended call for heating or cooling. Diagnostic mode is terminated when the exit command is given, the button is pressed and released without entering the diagnostic menu or 10 minutes has passed, whichever comes first.

When this mode is selected all installed temperature sensor valves (non-open and non-short) are shown on the 7-segment display. The following system status codes are displayed:

D Cooling D Percentage demand operation D Outdoor fan RPM D Active error codes

Outdoor Fan Mode

Diagnostic mode is only available while the system is in idle mode. This mode can be exited with the proper command or after 10 minutes has passed.

In diagnostic mode, the control energizes the outdoor fan at the highest speed. The control continuously displays the fan RPM on the 7-segment display.

PUMP-DOWN MODE OPERATION

1. Turn room thermostat OFF.

2. Install a set of refrigerant gauges on the system to monitor the pressure.

NOTE - All operation monitoring devices: High pressure switch, low pressure switch and compressor internal vacu um protection remain active in the system. This will prevent the compressor from recovering all the system refrigerant into the outdoor unit.

NOTE - If the pump-down jumper is in the ON position dur ing power-up, it is ignored.

3. Move the Pump-Down jumper (page 26 for location) from the OFF position to the ON position.

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Page 40

6. Monitor the low-side pressure at the outdoor unit. The internal vacuum protection in the compressor and/or

PUMP DOWN

OFF

PUMP DOWN

OFF

one of the pressure switches prevents full recovery of the refrigerant into the outdoor unit. When the system reaches this condition, the suction line service valve should be shut off and the Pump-Down Jumper moved back to the OFF position.

Figure 17. Pump-Down Jumper

4. Shut off the liquid line service valve to stop the flow of refrigerant into the indoor coil.

NOTE - The outdoor control will stay in pump-down mode for five minutes

, after which the outdoor control initiates a

compressor shutdown sequence.

5. After a three-second delay, the compressor and out door fan will ramp up to 100% capacity. (Indoor fan will remain OFF.)

7. Use a refrigerant recovery machine to recover the re maining refrigerant on the indoor side of the system.

Table 8. Field Test, Diagnostic Recall and Program Menu Options

Display

No Change - idle (*)

Solid . Solid  Solid  Solid  Solid 

String  

*No change indicates the display will continue to show whatever is currently being displayed for normal operations.

**Note once the error history is deleted it cannot be recovered. After the history is deleted, the unit will reset itself.

Display and action (normal operation)

No Change - idle (*)

Enter or exit field test and program mode.

Puts unit in diagnostic mode. (Displays ambient, coil, liquid sensor temperatures and any active error codes.)

Clears error history (**)

Enter diagnostic recall mode. Displays up to 10 error codes in memory.

Starts outdoor fan.

Enter unit code programming.

Table 9. Normal Operation Character Display String

Display

 

Display and action (normal operation) Display and action (configuration and test mode)

Idle mode — decimal flashes at 1 Hertz > 0.5 second ON, 0.5 second OFF

Cooling operation. Shows  and the cooling demand percentage. Example:    pause     pause   

Fan RPM. Shows  and the current fan RPM. Example:    pause     pause   

  in the display string represents the active error code(s) in the outdoor unit.

Example:    pause     pause     pause     pause    pause

  in the display string represents the outdoor ambient temperature in F at the outdoor sensor on the outdoor unit.

Example:    pause     pause   

 If enabled,  in the display string represents the outdoor coil temperature in F at the sensor on the outdoor unit.

Example:    pause     pause    pause    pause. Air conditioning units do not require an outdoor coil sensor. A 10K resistor, across pins 5 and 6 on the outdoor control sensor harness, prevents false outdoor coil sensor codes. The 10K resistor causes the 7-segment display to show a constant 77ºF coil (c) temperature value.

 If enabled,  in the display string represents the outdoor liquid line temperature in F at the sensor on the outdoor unit.

Example:    pause     pause    pause    pause pause     pause

 

 

COOLING AT

50% DEMAND

BY DEFAULT, COOLING OR HEATING, DEMAND, OUTDOOR FAN RPM, ACTIVE ERROR CODES

  displays when system is in pump down mode.

TYPICAL 7-SEGMENT ACTIVE COOLING OR HEATING DEMAND DISPLAY STRING





OUTDOOR

FAN RPM

AND OUTDOOR AMBIENT TEMPERATURE ARE DISPLAYED.

ACTIVE ERROR

CODE (IF PRESENT)



 

OUTDOOR

AMBIENT AIR

TEMP

STRING REVERTS BACK TO DEFAULT (SEE FIGURE 19 TO ENABLE)





OUTDOOR

COIL TEMP(*)

OUTDOOR COIL AND LIQUID LINE TEMPERATURES CAN BE

MANUALLY ENABLED. IF SYSTEM POWER IS RECYCLED, DISPLAY



OUTDOOR LIQUID

LINE TEMP



 

* Air conditioning units do not require an outdoor coil sensor. A 10K resistor, across pins 5 and 6 on the outdoor control sensor harness, prevents false outdoor coil sensor codes. The 10K resistor causes the 7-segment display to show a constant 77ºF coil (c) temperature value.

Figure 18. Typical 7-Segment Demand Display String

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Page 41

How to enable liquid line temperature information on a 7-segment display

Both coil and liquid line temperatures can be enabled for display either during normal demand operation or while in idle mode.

NOTE - If system power is recycled, display string reverts back to

default. Repeat the procedure which enables the outdoor coil and

liquid line temperature information. All temperatures are dis

played in Fahrenheit.

Yes

To enable temperature display, push and hold button next to 7-segment display until dash symbol appears and immediately release button. Once dash starts flashing, proceed to next step.

Push and hold the button until the solid

 appears on the 7-segment display.

Then, immediately release the button.

During thermostat demand of the outdoor control, the 7-segment display shows the cooling or heating (percent demand), fan RPM, error codes if present, and

outdoor ambient, Coil and liquid line temperatures need to be manually enabled to be displayed.





PERCENTAGE OF

MAXIMUM CAPACITY

NOTE - The coil and liquid line temperature readings are temporarily shown on the outdoor 7-segment display when the iComfort Wi-Fi® diagnostic screen is accessed.



FAN RPM





 

ACTIVE ERRORS

Outdoor control is either in IDLE

mode or heating / cooling

demand)



ONLY

OUTDOOR

Push and hold button until the flashing release button. The display shows the coil and liquid line temperature if there is an active demand running.

AMBIENT

 stops flashing then







OUTDOOR COIL

TEMP (*)

Wait until unit returns

to a active demand or

idle mode.



 

OUTDOOR LIQUID

LINE TEMP



Figure 19. Enabling Liquid Line Temperature Information

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Page 42

Configuring Unit

When installing a replacement outdoor control, the unit selection code may have to be manually assigned using the 7-seg ment display and push button on the control. The unit code sets unit type, capacity and outdoor fan RPM.

Configuring Unit Selection Code

Power-up - Unit selection code (two-digit number) displayed

represents unit size code (outdoor unit capacity). During initial power-up, firmware version, unit type, unit capacity and unit selection code will appear on the 7-segment display.

If three horizontal bars are shown in the 7-segment display during power-up, the outdoor control did not store the last configuration setting. If this happens, the configuration se quence for that setting must be repeated.

−

To enter unit selection mode, push and hold the

button next to the 7-segment display until dash symbol appears and immediately release button. Once dash starts flashing, proceed to next step.

Push and hold button until the solid  sequence is displayed on the 7-segment display then immediately release the button. This configuration sequence allows the installer to select unit selection code (number combination) that matches the outdoor unit type and inverter.

Press and hold the button during the  cycling display.

NOTE - Either the PU sequence will repeat 5 times and if a selection is not made the control will return to idle mode.

Yes

UNIT SELECTION

CODE



NOT

SELECTED

Outdoor control is in IDLE mode

(No heating or cooling demand)



Turn room thermostat

to OFF

1. When the correct unit section code is displayed, release but ton immediately. [Display flashes.]

2. Push and hold button until selection stops flashing during one of the three cycles. [Release push button]

3. If selection is not made during those three cycles the control returns to idle mode.

UNIT SELECTION

CODES

2-TON HEAT PUMP (XP20-024)

3-TON HEAT PUMP (XP20-036)

4-TON HEAT PUMP (XP20-048)

5-TON HEAT PUMP (XP20-060)

2-TON AIR CONDITIONER (XC20-024)

3-TON AIR CONDITIONER (XC20-036)

4-TON AIR CONDITIONER (XC20-048)

5-TON AIR CONDITIONER (XC20-060)

UNIT

SELECTED

NOT

SELECTED

If three horizontal bars display in any part of the 7-segment display string during power-up, the outdoor control did not store the unit selection code. If this occurs, the configuration sequence for that section of the display string must be repeated.

−

Figure 20. Configuring Unit Selection Code

XC20



FIRMWARE

VERSION

The outdoor control stores the unit type, automatically exits the con figuration mode and resets.

EXAMPLE 7-SEGMENT DISPLAY STRING





UNIT

TYPE





UNIT

CAPACITY



UNIT

CODE



(NO DEMAND)

IDLE MODE

Page 43

Reconfiguring Outdoor Control using

iComfort Wi-Fi

or iComfort S30

Thermostat

If any component of the HVAC system is changed, e.g. re placing an outdoor sensor, reconfiguring the system is required. To begin reconfiguring a system, select the

Setup tab.

System Overview

Refer to the applicable Thermostat Installer Setup Guide for configuration procedures.

IMPORTANT

Some scroll compressors have internal vacuum protector that will unload the scrolls when suction pressure goes below 20 psig. A hissing sound will be heard when the compressor is running unloaded. Protector will reset when low pressure in system is raised above 40 psig. DO NOT REPLACE COMPRESSOR.

The outdoor control provides the following functions:

D Internal switching of outputs. D Compressor anti-short-cycle delay (adjustable

through the thermostat interface.

D Five-strike lockout function. D High (S4) and low (S87) pressure switches.

D Ambient (RT13) and liquid line (RT36) temperatures

monitoring and protection.

COMPRESSOR PROTECTION — FIVE-STRIKE LOCKOUT

The five-strike lockout function is designed to protect the compressor from damage. The five-strike feature is used for both high (S4) and low (S87) pressure switches.

Resetting Five-Strike Lockout

Once the condition has been rectified, power to the outdoor control R terminal must be cycled OFF.

Diagnostic Information

The following diagnostic information is available through the thermostat's user interface. Refer to the applicable In staller System Setup Guide.

D Compressor anti-short-cycle delay timer status

D Cooling rate

D Compressor shift delay timer status

D High pressure switch status

D Low pressure switch status

D Compressor top cap switch status

D Liquid line temperature

D Outdoor ambient temperature

D Outdoor fan RPM

D Compressor active alarm

D Compressor Hz

D Inverter compressor short cycle

D Heat sink temperature

Installer Test

Verify the proper operation of the system by running the In staller Test feature through the thermostat interface. Refer to the applicable Installer System Setup Guide.

COMPRESSOR SHORT CYCLING DELAY

The outdoor control protects the compressor from:

D Short cycling (five minutes) during initial power-up. D Interruption in power to the unit. D Pressure or sensor trips. D Delay after demand is removed.

The delay is set by default for 300 seconds (five minutes) but can be changed through the thermostat interface.

Available settings are 60, 120, 180, 240 and 300 seconds.

CRANKCASE HEATER (HR1)

Compressors in all units are equipped with a 40-watt bellyband-type crankcase heater. HR1 prevents liquid from accumulating in the compressor. HR1 is controlled by the crankcase heater thermostat.

CRANKCASE HEATER THERMOSTAT (S40)

Thermostat S40 controls the crankcase heater in all units. S40 is located on the liquid line. When liquid line temperat ure drops below 50°F, thermostat S40 closes, energizing HR1. The thermostat opens, de-energizing HR1, once li quid line temperature reaches 70°F.

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Page 44

Maintenance

Outdoor Unit

Maintenance and service must be performed by a qualified installer or service agency. At the beginning of each cooling season, the system should be checked as follows:

1. Clean and inspect outdoor coil (may be flushed with a water hose). Ensure power is off before cleaning.

2. Outdoor unit fan motor is factory-lubricated and sealed. No further lubrication is needed.

3. Visually inspect all connecting lines, joints and coils for evidence of oil leaks.

4. Check all wiring for loose connections.

5. Check for correct voltage at unit (unit operating).

6. Check amp draw on outdoor fan motor.

7. Inspect drain holes in coil compartment base and clean if necessary.

NOTE - If insufficient heating or cooling occurs, the unit should be gauged and refrigerant charge should be checked.

Outdoor Coil

It may be necessary to flush the outdoor coil more fre quently if it is exposed to substances which are corrosive or which block airflow across the coil (e.g., pet urine, cotton wood seeds, fertilizers, fluids that may contain high levels of corrosive chemicals such as salts)

D Outdoor Coil — The outdoor coil may be flushed with

a water hose.

D Outdoor Coil (Coastal Area) — Moist air in ocean loca

tions can carry salt, which is corrosive to most metal. Units that are located near the ocean require frequent inspections and maintenance. These inspections will determine the necessary need to wash the unit includ ing the outdoor coil. Consult your installing contractor for proper intervals/procedures for your geographic area or service contract.

Indoor Unit

1. Clean or change filters.

2. Lennox blower motors are factory-lubricated and per manently 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. Refer to the unit information service manual for pressure drop tables and procedure.

4. Check all wiring for loose connections.

5. Check for correct voltage at unit. (blower operating)

6. Check amp draw on blower motor.

Indoor Coil

1. Clean coil if necessary.

2. Check connecting lines, joints and coil for evidence of oil leaks.

3. Check condensate line and clean if necessary.

Locations with Possibility of Heavy Snow or

Freezing Rain Accumulation

Heavy snow and/or freezing rain can interfere with the per formance of the outdoor fan assembly. Lennox recommends use of the optional snow guard (X8782) in these areas.

Figure 21. Snow Guard Top Cover — X8782

XC20

Page 45

Unit Wiring Diagrams

Figure 22. Typical Unit Wiring (XC20-024 and -036)

XC20

Page 46

Figure 23. Typical Unit Wiring (XC20-048 and -060)

XC20

Page 47

XC20 or XP20 iComfort Outdoor Unit Wiring Detail with Utility Load Shedding

XC20 OUTDOOR CONTROL

NOTE - For more information on Load-Shedding feature, see Electrical on page 24.

Figure 24. Load-Shedding Feature Wiring Diagram

XC20

Page 48

Factory Wiring Diagrams

Figure 25. Typical Factory Wiring (XC20-024 and -036)

XC20

Page 49

Figure 26. Typical Factory Wiring (XC20-048 and -060)

XC20

Page 50

Unit Sequence of Operation

The following figures illustrate the overall unit sequence of operation along with the operation of various pressure switches and temperature sensors. The figures also illustrate the use of the compressor anti-short-cycle function in relation to unit Status, unit Fault and lockout LED Codes and unit system operation interactions.

On 24 VAC power-up or outdoor reset, the outdoor control shall perform the following tasks:

1. Start the anti-short cycle 3-minute delay in the outdoor control.

2. Check status of the temperature sensor and pressure devices.

3. If the outdoor control does not detect any error codes, outdoor control sends 24 volts out on the

CNTCTR terminals to pull in the contactor coil. (Note - These checks take about 60 seconds.)

4. The contactor contacts pull IN and main power is applied to the compressor inverter.

From idle mode

Room thermostat sends a cooling percentage of maximum capacity demand to the main control board in the outdoor unit.

Yes

All switches closed

and sensors in operat

ing range.

Yes

Outdoor Control

1. Sends a demand to the compressor inverter to start and run the compressor up to the requested pumping capacity (Frequency in hertz).

2. Outputs a DC voltage on the DAN PWM and COM terminals to start and run the outdoor fan motor at the demand RPM.

3. Sends a communication signal into the indoor unit to start and run the supply fan motor at the demand air volume (CFM).

Check for status or

fault codes in the

outdoor control or room thermostat.

(NOTE - Refer to low

pressure and high

pressure switch flow

charts for sequence

of operation.

Diagnostic Screen

1. View the AIR CONDITIONING screen for current compressor frequency in hertz.

2. View the OUTDOOR CONTROL 7-Segment display to read the RPM of the outdoor fan motor.

3. View the AIR HANDLER screen for actual CFM of the indoor blower motor.

Figure 27. 24 Volt Power-Up or Outdoor Reset

XC20

Page 51

Y1 DEMAND

LOW

PRESSURE

SWITCH (S87)

CLOSED

CONTACTOR

ENERGIZED

INITIAL TRIP

SWITCH IS

IGNORED FOR

90 SECONDS

OPEN

CONTACTOR

DE-ENERGIZED

ANTI-SHORT

CYCLE TIMER

BEGINS

INCREMENT

5-STRIKE

COUNTER

LED ALERT CODE / OR

MODERATE

ALERT 410

DISPLAYED

LOW

PRESSURE

SWITCH (S87)

The thermostat terminates demand when the contactor

CLOSED

SWITCH IS CLOSED OR OUTDOOR

AMBIENT TEMPERATURE IS 15ºF

OR BELOW

is de-energized. If demand is satisfied when alarm is not active, the 5-strike counter resets.

2. Lockouts can be reset by cycling power off to the out

door control (A175) R terminal.

3. The low pressure switch is ignored by the system when

the outdoor temperature is below 15°F.

5-STRIKE

COUNTER

REACHES 5

WITHIN A SINGLE

Y1 DEMAND

LOW

PRESSURE

SWITCH (S87)

LOCKOUT

SERVICE

REQUIRED

OPEN

CLOSED

LED ALERT

CODE / OR

CRITICAL

ALERT 411

DISPLAYED

LED ALERT

CODE / OR

MODERATE

ALERT 410

DISPLAYED

SERVICE

REQUIRED

ANTI-SHORT

CYCLE TIMER

ENDS

CONTACTOR

ENERGIZED

LOW

PRESSURE

SWITCH (S87)

WAITING FOR

PRESSURE SWITCH TO

CLOSED

Figure 28. Low Pressure Switch (S87) Sequence of Operation (All Versions)

NORMAL

OPERATION

XC20

Page 52

Y1 DEMAND

OPEN

HIGH

PRESSURE

SWITCH (S4)

OPEN

CONTACTOR

DE-ENERGIZED

ANTI-SHORT

CYCLE TIMER

BEGINS

INCREMENT

5-STRIKE

COUNTER

CLOSED

HIGH

PRESSURE

SWITCH (S4)

1. The thermostat terminates demand when the contactor is

TOP CAP

SWITCH (S173)

CLOSED

de-energized. If demand is satisfied when alarm is not active, the 5-strike counter resets.

2. Lockouts can be reset by cycling power off to the outdoor control

(A175) R terminal.

5-STRIKE

COUNTER

REACHES 5

WITHIN A SINGLE

Y1 DEMAND

CONTACTOR

ENERGIZED

SERVICE

REQUIRED

OPEN

LED ALERT

CODE / OR

MODERATE

ALERT 412

DISPLAYED

ANTI-SHORT

CYCLE TIMER

ENDS

HIGH

PRESSURE

SWITCH (S4)

WAITING FOR

PRESSURE SWITCH TO

CLOSED

HIGH

PRESSURE

SWITCH (S4)

LOCKOUT

LED ALERT

CODE / OR

CRITICAL

ALERT 413

CLEARED

LED ALERT

MODERATE

DISPLAYED

CODE / OR

ALERT 412

SERVICE

REQUIRED

NORMAL

OPERATION

Figure 29. High Pressure Switch (S4) Sequence of Operation (All Versions)

XC20

Page 53

Component Testing

Component Testing Table of Contents

Verifying High Pressure and Low Pressure Switch Oper

ation 53.........................................

Compressor Operation, Checkout and Status / Error

Line Filter (Electromagnetic Compatibility Circuit - EMC) Operations, Checkout and Status / Error Codes 63...

Outdoor Fan Operation and Checkout 64...........

Codes 56.......................................

Crankcase Heater, Checkout and Status / Error Codes

59..................................

Compressor Sound Cover 60......................

Liquid Filter Drier (Heat Pumps only) 60.............

Ferrites 65......................................

Outdoor Control Operation, Checkout and Status / Error

Codes 66.......................................

Unit Sensor Operations, Checkout and Status / Error

Codes 67.......................................

Top Cap Switch Operation, Checkout and Status / Error

Codes 61.......................................

DC Inverter Control Operation, Checkout and Status /

Error Codes 70..................................

Reactor Operations, Checkout and Status /

Error Codes 62..................................

Emergency 24VAC Operation 75...................

Verifying High and Low Pressure Switch Operation

OPERATION :

The unit's pressure switches (LO PS - S87 and HI PS - S4) are factory-wired into the control on the LO-PS and HI-PS termin als, respectively.

Low Pressure Switch (LO-PS) — See figure 28 for low pressure switch sequence of operation.

High Pressure Switch (HI-PS) — See figure 29 for high pressure switch sequence of operation.

Pressure Switch Event Settings

The following pressures are the auto-reset event value triggers for low and high pressure thresholds:

D High Pressure (auto-reset) - trip at 590 psig; reset at 418. D Low Pressure (auto-reset) - trip at 40 psig; reset at 90.

CHECKOUT

Using a multimeter set to ohms with the terminals disconnected from the control board, check the resistance between the two terminals of the pressure switch. If the resistance reading is 0 ohms, the switch is closed.

Figure 30. Verifying High Pressure and Low Pressure Switch Operation

S4 HIGH PRESSURE SWITCH

S87 LOW PRESSURE SWITCH

XC20

Page 54

Y1 DEMAND

LOW

PRESSURE

SWITCH (S87)

CLOSED

CONTACTOR

ENERGIZED

INITIAL TRIP

SWITCH IS

IGNORED FOR

90 SECONDS

OPEN

CONTACTOR

DE-ENERGIZED

ANTI-SHORT

CYCLE TIMER

BEGINS

INCREMENT

5-STRIKE

COUNTER

LED ALERT

CODE / OR

MODERATE

ALERT 410

DISPLAYED

LOW

PRESSURE

SWITCH (S87)

CLOSED

SWITCH IS CLOSED OR OUTDOOR

AMBIENT TEMPERATURE IS 15ºF

1. The thermostat will terminate demand when the contactor is de-energized. If demand is satisfied when alarm is not active, the 5-strike counter will reset.

2. Lockouts can be reset by cycling power off to the outdoor control's (A175) R terminal.

3. The low pressure switch is ignored by the system when the outdoor temperature is below 15°F.

5-STRIKE

COUNTER

REACHES 5

WITHIN A SINGLE

Y1 DEMAND

LOW

PRESSURE

SWITCH (S87)

LOCKOUT

OR BELOW

XC20

SERVICE

REQUIRED

OPEN

ANTI-SHORT

CYCLE TIMER

ENDS

LED ALERT

CODE / OR

CRITICAL

ALERT 411

SERVICE

REQUIRED

DISPLAYED

CONTACTOR

ENERGIZED

LOW

PRESSURE

SWITCH (S87)

CLOSED

LED ALERT

CODE / OR

MODERATE

ALERT 410

DISPLAYED

WAITING FOR

PRESSURE

SWITCH TO

CLOSED

Figure 31. Low Pressure Switch (S87) Sequence of Operation (All Versions)

NORMAL

OPERATION

Page 55

Y1 DEMAND

OPEN

HIGH

PRESSURE

SWITCH (S4)

OPEN

CONTACTOR

DE-ENERGIZED

ANTI-SHORT

CYCLE TIMER

BEGINS

INCREMENT

5-STRIKE

COUNTER

CLOSED

HIGH

PRESSURE

SWITCH (S4)

1. The thermostat will terminate demand when the contactor is de-energized. If demand is satisfied when alarm is not active, the 5-strike counter will reset.

2. Lockouts can be reset by cycling power off to the outdoor control's

(A175) R terminal.

5-STRIKE

COUNTER

REACHES 5

WITHIN A SINGLE

Y1 DEMAND

TOP CAP

SWITCH (S173)

CLOSED

CONTACTOR

ENERGIZED

SERVICE

REQUIRED

OPEN

LED ALERT

CODE / OR

MODERATE

ALERT 412

DISPLAYED

ANTI-SHORT

CYCLE TIMER

ENDS

HIGH

PRESSURE

SWITCH (S4)

WAITING FOR

PRESSURE SWITCH TO

CLOSED

HIGH

PRESSURE

SWITCH (S4)

LOCKOUT

LED ALERT

CODE / OR

CRITICAL

ALERT 413

CLEARED

LED ALERT

CODE / OR

MODERATE

ALERT 412

DISPLAYED

SERVICE

REQUIRED

NORMAL

OPERATION

Figure 32. High Pressure Switch (S4) Sequence of Operation (All Versions)

XC20

Page 56

High and Low Pressure Switch Errors

System fault and lockout codes take precedence over system status codes (cooling, heating operating percentages or defrost/dehumidification). Only

Table 10. Outdoor Control 7-Segment Display Alert Codes - High and Low Pressure Switches

the latest active fault or lockout codes are displayed (if present). If no fault or lockout codes are active, then system status codes are displayed. Alert codes are also displayed on the iComfort Wi-Fi

Alert

Codes

E 410 Moderate

E 411 Critical

E 412 Moderate

E 413 Critical

Priority Alarm Description Possible Causes and Clearing Alarm

The outdoor unit cycled off due to low pressure switch opening.

The low pressure switch has opened 5 times within one hour. As a result, the outdoor unit is locked out

The outdoor unit high pressure switch has opened.

The high pressure switch has opened 5 times within one hour. As a result, the outdoor unit is locked out

NOTE - Unused on XC20. Used for heat pump applications only.

thermostat.

Unit pressure is below the lower limit. The system is shutdown. The low pressure switch closes above 90PSIG and opens below 40PSIG. Confirm that the system is properly charged with refrigerant. Check TXV, indoor unit blower motor, dirty filters or clogged refrigerant filter. Confirm that the evaporator coil is clean. The alarm clears after the pressure switch opens or after a power reset.

Low pressure switch error count reached 5 strikes. The low pressure switch for HFC410A opens at 40PSIG and resets at 90PSIG. Confirm that the system is prop erly charged with refrigerant. Check for clogged TXV, blockage to indoor unit blower motor, dirty filters or clogged refrigerant filter. Confirm that the evaporator coil is clean. The alarm clears after a power reset.

Unit pressure is above the upper limit. System is shut down. The high pressure switch opens at 590PSIG and closes at 418PSIG. Confirm that the system is prop erly charged with refrigerant. Check for clogged TXV, blockage to indoor unit blower motor, clogged refrigerant filter. Confirm that the outdoor unit is clean. The alarm clears after the pressure switch closes or a power reset.

For heating, indoor CFM may be set too low. For zoning system, zone CFM may be set too low.

Open high pressure switch error count reached 5 strikes. System is shut down. The high pressure switch for HFC410A will open at 590PSIG and close at 418PSIG. Confirm that the system is properly charged with refrigerant. Check condenser fan motor, clogged TXV, blockage to indoor unit blower motor, stuck reversing valve or clogged refrigerant filter. Confirm that the outdoor unit is clean. The alarm clears after a power reset.

For heating, indoor CFM may be set too low. For zoning system, zone CFM may be set too low.

Compressor Operation, Checkout and Status / Error Codes

OPERATION:

The compressor is a 380VAC three-phase variable-capacity scroll compressor that is approved for use with HFC410A refri gerant. The compressor, when connected to an inverter, is capable of operating in a running frequency range from 22 hertz up to a maximum of 70 Hertz (maximum hertz is dependent on compressor size). The compressor speed is determined by demand from the room thermostat.

CHECKOUT:

0.657

0.723

0.587

Figure 33. Compressor Operation, Checkout and Status/Error Codes

IMPORTANT: If compressor replacement is required, remove the compressor through the top of the unit. Removal through

the access panel is not possible.

0.657 0.657

0.657

0.723 0.723

0.587 0.587

XC20

Page 57

STATUS CODES:

When the compressor is running, the 7segment display on the outdoor control sends the current compressor demand (as a percentage) to the room thermostat. (Example: C 5 0 – compressor is running at 50% of maximum speed.)

Figure 34. Compressor Operation, Checkout and Status/Error Codes

ERROR CODES:

Table 11. Outdoor Control 7-Segment Display Alert Codes - Compressor

System fault and lockout codes take precedence over system status codes (cooling, heating operating percentages or defrost/dehumidification). Only the latest active fault or lockout codes are displayed (if present). If no fault or lockout codes are active, then system status codes are displayed. Alert codes are also displayed on the iComfort Wi-Fi

Inverter LED Flash

Alert

Codes

E 430 26 2 flashes 6 flashes

E 433 29 2 flashes 9 flashes

E 439 12 1 flash 2 flashes Moderate

Inverter

Code

Code (number of

flashes)

Red LED Green LED

thermostat..

Priority Alarm Description Possible Causes and Clearing Alarm

If condition is detected, outdoor unit compressor and fan stop. Antishort cycle is initiated. If condition occurs 10 times within an

Moderate / Critical

Compressor start failure

The inverter has de tected a compressor over-current condi tion

Compressor slow down due to high in put current.

hour, system is locked out.

Indicates poor connection at compressor harness, improper winding resistance, locked compressor rotor, or flooded com pressor.

To clear, disconnect power to outdoor unit and restart.

Error occurs when compressor peak phase current is greater than 28A. Inverter issues code 14 first and slows down to try to reduce the current. If the current remains high, outdoor unit com pressor and fan stop. Antishort cycle is initiated. If condition oc curs 5 times within an hour, system is locked out. To clear discon nect power to outdoor unit and restart.

Input current is approaching a high limit. Compressor speed automatically slows. The control continues sending the inverter speed demanded by the thermostat. The control sets indoor CFM and outdoor RPM to values according to demand percent age rather than the actual Hz. Alarm is automatically clear.

XC20

Page 58

System fault and lockout codes take precedence over system status codes (cooling, heating operating percentages or defrost/dehumidification). Only

Table 11. Outdoor Control 7-Segment Display Alert Codes - Compressor

Inverter LED Flash

Alert

Codes

E 440 13 1 flash 3 flashes Moderate

E 441 14 1 flash 4 flashes Moderate

E 600 N/A N/A N/A Critical

Inverter

Code

Code (number of

flashes)

Red LED Green LED

thermostat..

Priority Alarm Description Possible Causes and Clearing Alarm

Heat sink temperat ure is approaching limit. The com pressor speed auto matically slows to reduce heat sink temperature. The control sets indoor CFM and outdoor RPM to values ac cording to demand percentage rather than the actual Hz. Alarm is automatic ally cleared.

Compressor slow down due to high compressor current. Compressor current is approaching limit. The compressor speed automatically slows. The control sets indoor CFM and outdoor RPM to values according to demand percentage rather than the actu al Hz. Alarm is auto matically cleared..

Compressor has been cycled OFF by utility load-shedding function.

Issue: Feedback from supplier tear down of inverter indicates that the screws that hold the inverter to the inverter board were loose causing poor contact between these two components.

Corrective action: Tighten screws that hold the heat sink to the inverter control board.

NOTE: Wait 5 minutes to all capacitor to discharge before check ing screws.

Issue: Possible issue is system running at high pressures. Check for high pressure trips or other alert codes in room ther mostat and outdoor control.

Load-shedding function: Provides a method for a local utility company to limit the maximum power level usage of the outdoor unit. The feature is activated by applying 24 volts AC power to the L and C terminals on the outdoor control.

XC20

Page 59

Crankcase Heater, Checkout and Status / Error Codes

OPERATION:

CRANKCASE HEATER (HR1)

Compressors in all units are equipped with a 40 watt belly-band type crankcase heater. The heater prevents liquid from accumulating in the compressor. The heater is controlled by the crankcase heater thermostat.

CRANKCASE HEATER THERMOSTAT (S40)

Crankcase heater thermostat S40 controls the crankcase heater in all units and is located on the liquid line (see figure 2 for location).

1. When liquid line temperature drops below 50°F the thermostat closes which results in the heater being energized.

2. When liquid line temperature rises above 70°F the thermostat opens which results in the heater being de-energized.

Belly-Band Crankcase Heater -

240VAC, 40 Watts

Crankcase Heater Thermostat

Figure 35. Belly-Band Crankcase Heater Thermostat

CHECKOUT:

Belly-Band Crankcase Heater: Using meter set on ohms, check crankcase heater resistance. If resistance is 0 ohms or

infinite, replace the crankcase heater.

Figure 36. Checking Belly-Band Crankcase Heater

Crankcase Heater Thermostat: As the detected temperature changes, the resistance across the sensor changes. Table 15 on page 69 shows how the resistance varies as the temperature changes for this sensor.

NOTE - When checking the ohms across a sensor, be aware that a sensor showing a resistance value that is not range shown in table 15 on page 69, may be performing as designed. However, if a shorted or open circuit is detected, the sensor is faulty; the sensor needs to be replaced.

within the

XC20

Page 60

Figure 37. Checking Crankcase Heater Thermostat

STATUS CODE:

None

ERROR CODES:

None

Compressor Sound Cover

All units come with a soft-sided polyethylene molded outer shell compressor sound cover. The cover helps reduce any un wanted operating sounds from the compressor. The cover features a hook/loop closure system for ease of installation on the compressor.

Figure 38. Compressor Sound Cover

Liquid Line Filter Drier

A filter drier designed for all XC20 series model units is factory-installed in the liquid line. The filter drier is designed to remove moisture and foreign matter, which can lead to compressor failure.

Figure 39. Liquid Line Filter Drier

XC20

Page 61

Top Cap Switch Operation, Checkout and Status / Error Codes

OPERATION:

Top Cap Thermal Sensor Switch (S173)

Some units are equipped with a compressor-mounted normally closed temperature switch that prevents compressor dam age due to overheating caused by internal friction. The switch is located on top of the compressor casing. This switch senses the compressor casing temperature and opens at 239-257°F to shut off compressor operation. The auto-reset switch closes when the compressor casing temperature falls to 151-187°F, and the compressor is re-energized. This is a single-pole, single-throw (SPST) bi-metallic switch.

COMPRESSOR TOP CAP SWITCH

(SPST BI-METALIC SWITCH,

NORMALLY OPENS AT 239-257ºF,

AND CLOSES AT 151-187ºF

SWITCH COVER

TOP OF COMPRESS0R

Figure 40. Top Cap Thermal Sensor Switch

CHECKOUT:

Using a multimeter set to ohms, with the terminals disconnected from the system, check the resistance between the two terminals of the top cap switch. If the meter display does not change, the switch is open. If the meter display goes to infinite, the switch is closed.

Figure 41. Verifying Top Cap Thermal Sensor Switch

STATUS:

None

XC20

Page 62

ERROR:

Alert

Codes

E 422 Moderate

E 442 Critical

Priority Alarm Description Possible Causes and Clearing Alarm

Compressor top cap switch ex ceeding thermal limit.

The top cap switch has opened 5 times within one hour. As a result, the outdoor unit is locked out

thermostat.

Issue: One of the wires from the top cap switch had pulled off one of the TP termin als on the outdoor control board. Corrective Action: Reconnected wire onto top cap terminal.

When compressor thermal protection sensor opens 5 times within 1 hour, outdoor stops working. To clear, disconnect power to outdoor unit and restart.

Reactor Operations, Checkout and Status / Error Codes

OPERATION:

Reactor (Inductor or choke) is a passive twoterminal electrical component that stores energy in its magnetic field. Reactors are one of the basic components used in electronics where current and voltage change with time, due to the ability of induct ors to delay and reshape alternating currents.

CHECKOUT: Main Power ON – Voltage IN reactor should be the same as the voltage OUT. With main power OFF and reactor disconnec

ted from system; resistance between leads should be the same (brown IN to brown OUT, blue IN to blue OUT).

STATUS CODES:

None

ERROR CODES:

None

Table 12. Outdoor Control 7-Segment Display Alert Codes - Top Cap Switch

Voltage “IN” same as Voltage “OUT”

Figure 42. XC/XP 20-024 and -036 Reactor

208/240 Voltage “IN”

Figure 43. XC/XP 20-048 and -060 Reactor

XC20

208/240 Voltage “OUT”

Page 63

Line Filter (Electromagnetic Compatibility Circuit - EMC) Operations, Checkout and Status / Error Codes

OPERATION:

The line filter reduces the unintentional conducted emission from the equipment, to a level sufficient to pass regulatory limits (such as FCC part 15).

The filter is rated at 208/230 volt, 30 amp maximum, 60 Hertz.

NOTE - The 2- and 3-ton inverters have the EMC builtin. The 4- and 5-ton units have an external device (see illustration below).

NOTE - A line filter is an electronic filter which is placed between electronic equipment and an external power source in order to attenuate conducted radio frequency interference (RFI). RFI is also known as electromagnetic interference (EMI).

CHECKOUT:

Voltage IN should read the same value as the Voltage OUT. With filter isolated from system, resistance between L1 and L2 should be the same as resistance between N1 and N2.

STATUS CODES:

None

ERROR CODES:

None

208/240

Voltage IN

208/240

Voltage OUT

Figure 44. XC20 4- and 5-ton filter board (EMC)

XC20

Page 64

Outdoor Fan Operation and Checkout

OPERATION:

These units use an integrated control and motor that is programmed for variable-capacity operation. The fan speed is

controlled by the iComfort Wi-Fi

CHECKOUT:

VAC Voltage Check

Check for 208/240 VAC power at inverter contactor (red wires) (see figure 45).

With unit operating, check for main VAC to motor and outdoor control VDC output to motor:

1. No voltage present – Check main power

2. Voltage present – Perform DC volt checks (19 -23 VDC between FAN PWM and COM) (see figure 45)

or iComfort® S30 thermostat.

Perform DC volt checks (19 -23 VDC between FAN PWM and COM).

Figure 45. VAC Voltage Check

XC20

Page 65

VDC Voltage Check: Check for VDC out of Fan PWM and COM. VDC output reading is determined by the percentage of room thermostat de mand.

1. No voltage present – Remove wires from control and check for VDC. If there is no voltage present, then replace out door control.

2. Voltage present – Perform a 9-volt battery test on motor (see figure 46).

BLACK LEAD

CONNECT B4 FAN MOTOR BLACK

COMMON WIRE TO 9V BATTERY

NEGATIVE TERMINAL

NEGATIVE TERMINAL POSITIVE TERMINAL

FULLY CHARGED 9V BATTERY

BROWN LEAD

CONNECT B4 FAN MOTOR WIRE TO 9V BATTERY POSITIVE

TERMINAL

Figure 46. VDC Voltage Check

STATUS OR ERROR CODES:

There is no feedback from the outdoor fan motor to the outdoor control therefore no status or error codes are displayed on either the outdoor control or iComfort Wi-Fi

or iComfort® S30 room thermostat.

NOTE - If the outdoor fan does not operate at the correct RPM, or does not start, the system will shut be down by other protection components such as the high and low pressure switches which will generate error code(s).

Ferrites

Electronic cabling and wires, by virtue of their lengthtowidth ratios, are perfect natural antennas. In the presence of highspeed microprocessor signals, cables will conduct, radiate, and receive unwanted highfrequency signals. Use an in sertion-loss device, such as a ferrite suppressor as shown below, to control radio-frequency (RF) interference.

Ferrites are consistently stable over time and over wide temperature ranges, and provide RF suppression without causing large current losses.

Figure 47. Ferrites

XC20

Page 66

Outdoor Control Operation, Checkout and Status / Error Codes

OPERATION:

The outdoor control is a microprocessor-based device for use with variable-capacity compressors up to 5-tons in capacity operating on 24VAC residential power. The outdoor control integrates the functionality of maintaining compressor speed, demand, defrost and fan PWM controls. The outdoor control is self-configuring. During start-up the outdoor control selects one of two configurations  variable-capacity air conditioner or variable-capacity heat pump.

7-SEGMENT

DISPLAY

PUSH

BUTTON

NOTE - The green LED located on the outdoor control flashes when communication occurs between the outdoor control and either the thermostat or the inverter.

WHEN UNIT IS IN PUMP-DOWN MODE,  WILL BE DISPLAYED

TO ACTIVATE PUMP-DOWN MODE, REFER TO PUMP-DOWN

ON 7-SEGMENT.

CYCLE SEQUENCE ON PAGE 39.

Figure 48. Outdoor Control Unit

STATUS CODES:

Table 13. Outdoor Control 7-Segment Display Alert Codes - Outdoor Control Status

Alert Codes Priority Alarm Description Possible Causes and Clearing Alarm

Compressor has

E 600 Critical

E 601 Critical

been cycled OFF on utility load shedding.

Outdoor unit has been cycled OFF on low temperature protection.

or iComfort

Low temperature Protection: Outdoor unit will not operate when the outdoor temperature is at or below 4°F (20°C). If the unit is operating and the outdoor temperature drops below 4°F (20°C), the unit will continue to operate until the room thermostat is satisfied or the outdoor temperature drops to 15°F (26°C). (Outdoor unit ambient sensor provides temperature readings.)

S30 thermostat.

XC20

Page 67

ERROR CODES:

Alert

Codes

E 105 Moderate

E 120 Moderate

E 124 Critical

E 125 Critical

E 131 Critical

E 132 Critical Internal software error. Replace outdoor control.

Priority Alarm Description Possible Causes and Clearing Alarm

The outdoor control has lost com munication with either the thermo stat or indoor unit.

There is a delay in the outdoor unit responding to the system.

The iComfort WiFi® thermostat has lost communication with the outdoor unit for more than 3 minutes.

There is a hardware problem with the outdoor control.

The outdoor unit control parameters are corrupted

or iComfort

S30 thermostat.

Equipment is unable to communicate. Indicates numerous message errors. In most cases errors are related to electrical noise. Make sure high voltage power is separated from RSBus. Check for miswired and/or loose connections between the stat, indoor unit and outdoor unit. Check for a high voltage source of noise close to the system. Fault clears after communication is restored.

Typically, this alarm/code does not cause any issues and will clear on its own. The alarm / code is usually caused by a delay in the outdoor unit responding to the thermostat. Check all wiring connections. Cleared after unresponsive device responds to any in quiry.

Equipment lost communication with the thermostat. Check the wiring connections, ohm wires and cycle power. The alarm stops all associated HVAC operations and waits for a heartbeat message from the unit that's not communicating. The alarm / fault clears after communication is reestablished.

There is a control hardware problem. Replace the outdoor control if the problem pre vents operation and is persistent. The alarm / fault is cleared 300 seconds after the fault recovers.

Reconfigure the system. Replace the control if heating or cooling is not available.

Unit Sensor Operations, Checkout and Status / Error Codes

OPERATION

Pins 5 and 6 (No Sensor)

There is no sensor located on positions 5 and 6 of the connector. A resistor installed between pins 5 and 6 on the cable harness provides continuity for this circuit. This resistor (location shown in figure 50) provides resistance value between

Table 14. Outdoor Control 7-Segment Display Alert Codes - Outdoor Control Errors

314669 and 3779 ohms the coil temperature sensor is out of range or faulty (see table 15 on page 69). If resistor is damaged or missing, order re placement harness assembly (101334-05).

Ambient temperatures, as read by the ambient temperature sensor (shown in figure 50) which are below -35°F (-37°C) or above 120°F (48°C) trigger a fault condition. If the ambient sensor is open, shorted, or out of the temperature range of the sensor, the control does not perform demand defrost operation. The control reverts to time/temperature defrost operation and displays the appropriate alert code (see table 15 on page 69). Heating and cooling operation is allowed in this fault condition.

Liquid line temperatures below -40°F (-40°C) or above 140°F (60°C) trigger a fault condition and result in the appropriate alarm code (see table15 on page 69). The outdoor control uses the liquid line sensor to change the fan speed, allowing cooling operation at lowered ambient temperatures.

. If the resistor becomes damaged or lost, the outdoor control generates a false error code indicating

Ambient Temperature Sensor (RT13)

Liquid Line Temperature Sensor (RT36)

XC20

Page 68

SENSOR

NONE

TEMP RANGE ºF

(ºC)

N/A

RESISTANCE VALUES

RANGE (OHMS)

314669 and 3779

PIN# / WIRE

SLEEVE COLOR

6 AND 5

OUTDOOR

AMBIENT

LIQUID LINE

OUTDOOR

AMBIENT

LIQUID LINE

-40 (-40) TO 140 (60)

BLACK WIRES WITH

BLACK SLEEVE

BLACK WIRES WITH

YELL0W SLEEVE

336,000 to 2,487 (see table 15 on page 69 for exact temperature to ohm readings).

10 K OHM RESISTOR

4 AND 3

(BLACK)

2 AND 1

(YELLOW)

TEMPERATURE

SENSOR HARNESS

Figure 49. Temperature Sensor Specifications

CHECKOUT

Sensors connect to the outdoor control through a field‐replaceable harness assembly that plugs into the outdoor control. Through the sensors, the control detects outdoor ambient, coil and liquid temperature fault conditions. As the detected tem perature changes, the resistance across the sensor changes. Check sensor operation by reading ohms across pins shown in figure 49.

NOTE - When checking the ohms across a sensor, be aware that a sensor showing a resistance value that is not

within the range shown in figure 49, may be performing as designed. However, if a shorted or open circuit is detected, then the sensor may be faulty and the sensor harness will need to be replaced.

XC20

OUTDOOR AMBIENT

TEMPERATURE

SENSOR

LIQUID LINE SENSOR

CRANKCASE HEATER

THERMOSTAT (S40) OPENS AT

70ºF, CLOSES AT 50ºF

Figure 50. Temperature Sensor Locations

Page 69

Degrees Fahr enheit

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 128508

127.3 3223 54.6 17616 20.0 46281 -13.2 131320

124.7 3407 53.9 17942 19.4 47014 -13.9 134227

122.1 3592 53.2 18273 18.9 47759 -14.5 137234

119.7 3779 52.5 18607 18.4 48517 -15.2 140347

117.5 3968 51.9 18945 17.8 49289 -15.9 143571

115.3 4159 51.2 19287 17.3 50074 -16.5 146913

113.2 4351 50.5 19633 16.8 50873 -17.2 150378

111.2 4544 49.9 19982 16.3 51686 -17.9 153974

109.3 4740 49.2 20336 15.7 52514 -18.6 157708

107.4 4937 48.5 20695 15.2 53356 -19.3 161588

105.6 5136 47.9 21057 14.7 54215 -20.1 165624

103.9 5336 47.3 21424 14.1 55089 -20.8 169824

102.3 5539 46.6 21795 13.6 55979 -21.5 174200

100.6 5743 46.0 22171 13.1 56887 -22.3 178762

99.1 5949 45.4 22551 12.5 57811 -23.0 183522

97.6 6157 44.7 22936 12.0 58754 -23.8 188493

96.1 6367 44.1 23326 11.5 59715 -24.6 193691

94.7 6578 43.5 23720 11.0 60694 -25.4 199130

93.3 6792 42.9 24120 10.4 61693 -26.2 204829

92.0 7007 42.3 24525 9.9 62712 -27.0 210805

90.6 7225 41.7 24934 9.3 63752 -27.8 217080

89.4 7444 41.1 25349 8.8 64812 -28.7 223677

88.1 7666 40.5 25769 8.3 65895 -29.5 230621

86.9 7890 39.9 26195 7.7 67000 -30.4 237941

85.7 8115 39.3 26626 7.2 68128 -31.3 245667

84.5 8343 38.7 27063 6.7 69281 -32.2 253834

83.4 8573 38.1 27505 6.1 70458 -33.2 262482

82.3 8806 37.5 27954 5.6 71661 -34.1 271655

81.2 9040 37.0 28408 5.0 72890 -35.1 281400

80.1 9277 36.4 28868 4.5 74147 -36.1 291774

79.0 9516 35.8 29335 3.9 75431 -37.1 302840

78.0 9757 35.2 29808 3.4 76745 -38.2 314669

77.0 10001 34.7 30288 2.8 78090 -39.2 327343

76.0 10247 34.1 30774 2.3 79465

75.0 10496 33.5 31267 1.7 80873

74.1 10747 33.0 31766 1.2 82314

73.1 11000 32.4 32273 0.6 83790

72.2 11256 31.9 32787 0.0 85302

71.3 11515 31.3 33309 -0.5 86852

70.4 11776 30.7 33837 -1.1 88440

69.5 12040 30.2 34374 -1.7 90068

68.6 12306 29.6 34918 -2.2 91738

67.7 12575 29.1 35471 -2.8 93452

66.9 12847 28.6 36031 -3.4 95211

66.0 13122 28.0 36600 -4.0 97016

65.2 13400 27.5 37177 -4.6 98870

64.4 13681 26.9 37764 -5.2 100775

63.6 13964 26.4 38359 -5.7 102733

62.8 14251 25.8 38963 -6.3 104746

62.0 14540 25.3 39577 -6.9 106817

61.2 14833 24.8 40200 -7.5 108948

60.5 15129 24.2 40833 -8.2 11114 1

59.7 15428 23.7 41476 -8.8 113400

59.0 15730 23.2 42130 -9.4 115727

58.2 16036 22.6 42794 -10.0 118126

57.5 16345 22.1 43468 -10.6 120600

Resistance

Degrees Fahr enheit

Resistance

Degrees Fahr enheit

Resistance

Degrees Fahr enheit

Resistance

Table 15. Ambient and Liquid Line Sensors Temperature / Resistance Range

XC20

Page 70

ERROR CCOCODES:

Table 16. Outdoor Control 7-Segment Display Alert Codes - Outdoor Control Errors

or iComfort® S30

are active, then system status codes are displayed. Alert codes are also displayed on the iComfort Wi-Fi thermostat.

Alert

Codes

E 180 Critical

E 416

E 424 Moderate Faulty outdoor liquid line sensor Sensor is open or shorted. Replace the sensor.

Priority Alarm Description Possible Causes and Clearing Alarm

During normal operation, after the outdoor control recognizes sensors, the alarm will be sent only if valid temperature reading is lost. Compare outdoor sensor resistance to temperature/resistance charts in unit installation instructions. Replace sensor pack if necessary. At the beginning of (any) configuration, furnace or air-handler control will detect the presence of the sensor(s). If detected (reading in range), appropriate feature will be set as 'installed' and shown in the iComfort Wi-Fi screen. The alarm / fault will clear upon configuration, or sensing normal values.

Coil sensor is detected as open or shorted, or temperature is out of coil sensor range. Outdoor unit control will not perform demand or time/temperature defrost operation. System will still heat or cool. Check the resistance of the coil sensor and compare to temperature resistance chart. Replace coil sensor if needed. The alarm clears when outdoor unit control detects proper coil sensor readings or after a power reset.

Moderate /

Critical

The iComfort Wi-Fi® thermostat has found a problem with the outdoor unit's ambient temperature sensor.

The outdoor coil sensor is either open, short-circuited or the temperature is out of sensor range. As a result the outdoor unit control will not perform defrost.

thermostat 'About'

DC Inverter Control Operation, Checkout, Status / Error Codes

OPERATION OF COMPONENTS:

Electromagnetic compatibility circuit (EMC): EMC ensures the correct operation of different equipment items which use or respond to electromagnetic phenomena. It also helps to negate the effects of interference. NOTE - The 2- and 3-ton inverter

has an EMC builtin. The 4- and 5-ton units have an external inverter.

CONVERTER:

Converts AC (alternating current) to DC (direct current).

POWER FACTOR CORRECTION (PFC) CIRCUIT:

The PFC module is an integrated part of the outdoor inverter that monitors the DC bus for high, low and abnormal voltage conditions. If any of these conditions are detected, the PFC function and compressor will stop.

INTELLIGENT (INVERTER) POWER MODULE (IPM): The IPM converts DC power into AC power. The control method is known as pulse width modulation (PWM). This means the

DC is switched on and off very quickly (chopped) by the transistor switches to make simulated AC at required frequency and voltage.

COMMUNICATION CONTROL CIRCUIT:

Receives and sends message between the inverter and the outdoor control.

Power Factor Correction Circuit

Converter

Intelligent Power Module

Communication Control

Electromagnetic Compatibility Circuits

Figure 51. 2- and 3-Ton Unit Inverter

XC20

Page 71

Heat Sink

Converter

Power Factor Correction Circuit

Intelligent Power Module

Communication Control

Figure 52. 4- and 5-Ton Unit Inverter

STATUS CODES:

Table 17. Outdoor Control 7-Segment Display Alert Codes and Inverter LED Flash Codes

NOTE - System fault and lockout codes take precedence over system status codes (cooling, heating operating percentages or defrost/de humidification). Only the latest active fault or lockout codes are displayed (if present). If no fault or lockout codes are active, then system status codes are displayed. Alert codes are also displayed on the iComfort Wi-Fi

Inverter LED Flash

Alert

Codes

N/A ON OFF N/A XC 20-024 and -036 only: Indicates inverter is operating normally.

N/A ON ON N/A XC 20-048 and -060 only: Indicates inverter is operating normally.

N/A OFF OFF N/A Indicates inverter is NOT energized.

Code (number of flashes)

Red LED

Green

LED

Priority Alarm Description Possible Causes and Clearing Alarm

or iComfort® S30 thermostat.

ERROR CODES:

Table 18. Outdoor Control 7-Segment Display Alert Codes and Inverter LED Flash Codes

Inverter LED Flash

Alert

Codes

E 423 40 4 flashes OFF

E 426 N/A N/A N/A Critical Excessive inverter alarms

Inverter

Code

Code (number of flashes)

Red LED Green LED

or iComfort

Priority Alarm Description Possible Causes and Clearing Alarm

Moderate

/ Critical

S30 thermostat.

The inverter has detected a circuit problem.

Control will lock out after 10 strikes within an hour. To clear disconnect power to outdoor unit and restart.

After ten faults within one hour, control will lock out.

Indicates poor system operation. Review history of alarms to resolve system setup. Check condenser fan motor, TXV, indoor unit blower motor, stuck reversing valve, over-charge, undercharge, and clogged refriger ant filter.

To clear error, disconnect power to outdoor unit and re start. Inverter alarms 12 to 14 and 53 do not count to wards this lock out condition.

XC20

Page 72

NOTE - System fault and lockout codes take precedence over system status codes (cooling, heating operating percentages or defrost/dehumidification).

Table 18. Outdoor Control 7-Segment Display Alert Codes and Inverter LED Flash Codes

Only the latest active fault or lockout codes are displayed (if present). If no fault or lockout codes are active, then system status codes are displayed. Alert codes are also displayed on the iComfort Wi-Fi

or iComfort

Inverter LED Flash

Alert

Codes

Inverter

Code

Code (number of flashes)

Priority Alarm Description Possible Causes and Clearing Alarm

Red LED Green LED

E 427 21 2 flashes 1 flash

E 428 22 2 flashes 2 flashes

E 429 23 2 flashes 3 flashes

E 430 26 2 flashes 6 flashes

E 431 27 2 flashes 7 flashes

E 432 28 2 flashes 8 flashes

Moderate

/ Critical

Moderate

/ Critical

Moderate

/ Critical

Moderate

/ Critical

Moderate

/ Critical

Moderate

/ Critical

S30 thermostat.

The inverter has detected a DC peak fault condition

The inverter has detected a high main input current con

dition

Compressor start failure.

The inverter has detected a DC link high voltage condi tion.

If condition (55A or higher) is detected, outdoor unit will stop (compressor and fan). Antishort cycle is initiated. If peak current (55A or higher) occurs 10 times within an hour, system will lock out.

Indicates high pressure, condenser fan failure, locked compressor rotor or overcharge.

To clear, disconnect power to outdoor unit and restart. If condition is detected, outdoor unit will stop (compressor

and fan). Antishort cycle is initiated. If condition occurs 5 times within an hour, system will lock out.

Indicates high pressure, condenser fan failure or over charge. To clear, disconnect power to outdoor unit and restart.

Issues:

(1) If DC link power in inverter does not rise above 180 VDC for 2- and 3-ton models, 250 VDC for 4- and 5-ton models, within 30 seconds, the outdoor control will dis play a moderate code.

(2) Capacitors on inverter do not properly charge.

Corrective Actions:

(1) check for proper main power to outdoor unit and for any loose electrical connections.

(2) Outdoor control boards with part # 103686-03 have software update to delay the de-energizing of the revers ing valve by four seconds when coming out of defrost.

If condition is detected, outdoor unit will stop (compressor and fan). Antishort cycle is initiated. If condition occurs 10 times within an hour, system will lock out.

Indicates poor connection at compressor harness, im proper winding resistance, locked compressor rotor, or flooded compressor.

To clear, disconnect power to outdoor unit and restart.

Issues:

(1) Indicates power interruption, brownout, poor electrical connection or loose inverter input wire.

(2) System testing was set up and code was generated when the reversing valve is de-energized coming out of defrost (code appears with or without 30 compressor delay).

Corrective Actions:

(1) Check for proper main power to outdoor unit and for any loose electrical connections.

(2) Outdoor control boards with part # 103686-03 have software update to delay the de-energizing of the revers ing valve by four seconds when coming out of defrost.

Error occurs when the DC link capacitor voltage is greater than 480VDC. If condition is detected, outdoor unit will stop (compressor and fan). Antishort cycle is initiated. If condition occurs 10 times within an hour, system will lock out. System will stop. To clear, disconnect power to out door unit and restart.

XC20

Page 73

NOTE - System fault and lockout codes take precedence over system status codes (cooling, heating operating percentages or defrost/dehumidification).

Table 18. Outdoor Control 7-Segment Display Alert Codes and Inverter LED Flash Codes

Inverter LED Flash

Alert

Codes

E 433 29 2 flashes 9 flashes

E 434 53 5 flashes 3 flashes

E 435 60 6 flashes OFF

E 436 62 6 flashes 2 flashes

E 437 65 6 flashes 5 flashes

E 438 73 7 flashes 3 flashes

Inverter

Code

Code (number of flashes)

Red LED Green LED

or iComfort

Priority Alarm Description Possible Causes and Clearing Alarm

Moderate

/ Critical

Moderate / Critical

Moderate

/ Critical

Moderate / Critical

Moderate

/ Critical

Moderate / Critical

S30 thermostat.

The inverter has detected a compressor over-current condition.

Outdoor control has lost com munications with the inverter for greater than 3 minutes. Outdoor control will stop all compressor demands, re cycle power to the inverter by de-energizing the contactor for 2 minutes. If this occurs 3 time in one thermostat call, the outdoor unit will locked out and display a critical code.

Inverter internal error.

Inverter heat sink temperat ure exceeded limit. Occurs when the heat sink temperat ure exceeds the inverter limit. Inverter issues code 13 first, then slows down to allow the heat sink to cool. If temperat ure remains high, outdoor unit stops (compressor and fan). Anti-short cycle is initi ated. If condition occurs 5 times within an hour, system is locked out. To clear, dis connect power to outdoor unit and restart.

Heat sink temperature sensor fault has occurred (temperature less than 4 ºF or greater than 264ºF after 10 minutes of operation).

The inverter has detected a PFC over current condition. This would be caused by a high load condition, high pressure, or outdoor fan fail ure.Outdoor control will dis play the code when the in verter has the error. After 3 minutes, the inverter will re set and the compressor will turn on again. If it happens 10 times within a 60 minute rolling time period, the OD control will lock out operation of the outdoor unit and dis play a critical code.

Error occurs when compressor peak phase current is greater than 28A. Inverter will issue code 14 first and slow down to try to reduce the current. If the current remains high, outdoor unit will stop (compressor and fan). Antishort cycle is initiated. If condition occurs 5 times within an hour, system will lock out. To clear disconnect power to outdoor unit and restart.

Issues:

(1) Loose electrical connections.

(2) Interruption of main power to inverter.

Corrective Actions:

(1) Check all electrical connections.

(2) Check for proper main power to inverter.

When this error occurs, the outdoor control will cycle power to the inverter by opening the contactor for 2 minutes. Check that the EEPROM is properly seated. After power is cycled to the inverter 3 times, the outdoor unit is locked out.

Issue: Feedback from supplier tear down of inverter in dicates that the screws that hold the inverter to the invert er board were loose causing poor contact between these two components.

Corrective Action: Tighten screws that hold the heat sink to the inverter control board.

NOTE: Wait five minutes to all capacitor to discharge be fore checking screws.

This occurs when the temperature sensor detects a tem perature less than 0.4ºF or greater than 264ºF after 10 minutes of operation. If condition is detected, outdoor unit will stop (compressor and fan). Antishort cycle is initi ated. If condition occurs 5 times within an hour, system will lock out. To clear disconnect power to outdoor unit and restart. If problem persists, replace inverter.

Issue: Possible issue is system running at high pres sures. Check for high pressure trips or other alert codes in room thermostat and outdoor control.

XC20

Page 74

NOTE - System fault and lockout codes take precedence over system status codes (cooling, heating operating percentages or defrost/dehumidification).

Table 18. Outdoor Control 7-Segment Display Alert Codes and Inverter LED Flash Codes

Inverter LED Flash

Alert

Codes

E 439 12 1 flash 2 flashes Moderate

E 440 13 1 flash 3 flashes Moderate

E 441 14 1 flash 4 flashes Moderate

Inverter

Code

Code (number of flashes)

Red LED Green LED

or iComfort

Priority Alarm Description Possible Causes and Clearing Alarm

S30 thermostat.

Compressor slowdown due to high input current.

Heat sink temperature is ap proaching limit. The com pressor speed automatically slows to reduce heat sink temperature. The control sets indoor CFM and outdoor RPM to values according to demand percentage rather than the actual Hz. Alarm is automatically cleared.

Compressor slowdown due to high compressor current. Compressor current is ap proaching limit. The com pressor speed automatically slows. The control sets in door CFM and outdoor RPM to values according to de mand percentage rather than the actual Hz. Alarm is auto matically cleared..

Input current is approaching a high limit. Compressor speed will automatically slow down. The control contin ues sending the inverter speed demanded by the thermo stat. The control will set indoor CFM and outdoor RPM to values according to demand percentage rather than the actual Hz. Alarm is automatically clear.

Issue: Feedback from supplier tear down of inverter in dicates that the screws that hold the inverter to the invert er board were loose causing poor contact between these two components.

Corrective action: Tighten screws that hold the heat sink to the inverter control board.

NOTE: Wait 5 minutes to all capacitor to discharge before checking screws.

Issue: Possible issue is system running at high pres sures. Check for high pressure trips or other alert codes in room thermostat and outdoor control.

XC20

Page 75

Emergency 24VAC System Operation

The Y terminal located on the outdoor control allows the outdoor unit to be cycled ON and OFF using 24VAC inputs. The outdoor unit will operate at 100% capacity in this configuration.

The following wiring diagrams display the wiring changes needed to switch a full communicating system to a non-communic ating system with the XC20 running in emergency mode (24VAC inputs to outdoor unit).

iComfort Wi-Fi or iComfort S30



Thermostat,

Communicating Air Handler and XC20

Communicating Air

Handler or

Furnance

iComfort ® Wi-Fi

or iComfort® S30

THERMOSTAT



XC20 UNIT

RSBus

24VAC Thermostat

NOTE 1 and 2

NOTES:

1. Move one wire on both indoor and outdoor controls from terminals i+ to Y1 for 24VAC operation on air conditioner and indoor unit.

2. Disconnect the i- wire from terminal strip and tape.

3. Do not disconnect wires form the XC20 R and C terminals, both are required.

Communicating Air

Handler or

Furnance

(Non−Communicating Mode)

Emergency 24VAC

XC20 UNIT

NOTE 3

Figure 53. Emergency 24VAC System Operation

System Refrigerant

IMPORTANT !

The system must be operating at full capacity during charging. Increase (heat) or decrease (cooling) the thermostat setting by 5°F to create system demand. Confirm outdoor unit running capacity on the display on the outdoor control. Value should be 100%.

This section outlines the procedures to:

1. Connect a gauge set for testing and charging as illustrated in fig

ure 54.

2. Check and adjust indoor airflow as described in figure 55.

3. Add or remove refrigerant using the weigh-in method shown in

figure 56.

4. Verify the charge using the subcooling method described in fig

ure 57.

IMPORTANT: Unit must be operating at 100% input to be charged

properly.

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.

INDOOR AIRFLOW CHECK

Check airflow using the Delta-T (DT) process using the illustration in figure 55.

The diagnostic screen on the thermostat or outdoor control 7-seg ment display shows indoor and outdoor motor CFMs or RPMs.

XC20

Page 76

MANIFOLD GAUGE SET

LOW

HIGH

GAUGE SET

CONNECTIONS FOR TESTING AND CHARGING

REFRIGERANT TANK

CHARGE IN

LIQUID PHASE

DIGITAL SCALE

TEMPERATURE

SENSOR

A. CLOSE MANIFOLD GAUGE SET VALVES AND CONNECT THE CENTER HOSE TO A CYLINDER OF HFC-410A SET FOR LIQUID PHASE CHARGING.

B. CONNECT THE MANIFOLD GAUGE SET'S LOW PRESSURE SIDE TO THE SUCTION LINE SERVICE PORT.

C. CONNECT THE MANIFOLD GAUGE SET'S HIGH PRESSURE SIDE TO THE LIQUID LINE SERVICE PORT.

D. POSITION TEMPERATURE SENSOR ON LIQUID LINE NEAR LIQUID LINE SERVICE PORT.

TO LIQUID

LINE SERVICE

PORT

SUCTION LINE

TEMPERATURE SENSOR

(LIQUID LINE)

Figure 54. Gauge Set Connections

OUTDOOR UNIT

TEMPERATURE OF AIR ENTERING INDOOR COIL ºF

AIRFLOW

INDOOR COIL

DRY

BULB

53º

ALL TEMPERATURES ARE EXPRESSED IN ºF

ASSUME DT = 15 AND A TEMP. = 72º, BELOW C TEMPERATURES REQUIRE ACTION:

Cº T

53º 19 – 15 = 4 INCREASE THE AIRFLOW 58º 14 – 15 = -1 (WITHIN +3º RANGE) NO CHANGE 62º 10 – 15 = -5 DECREASE THE AIRFLOW

DROP

19º

AIR FLOW

– DT = ºF ACTION

DROP

INDOOR COIL

AIR FLOW

64º

WET

BULB

72º

DRY BULB

80 24 24 24 23 23 22 22 22 20 19 18 17 16 15 78 23 23 23 22 22 21 21 20 19 18 17 16 15 14 76 22 22 22 21 21 20 19 19 18 17 16 15 14 13 74 21 21 21 20 19 19 18 17 16 16 15 14 13 12

DRY-BULB

72 20 20 19 18 17 17 16 15 15 14 13 12 11 10 70 19 19 18 18 17 17 16 15 15 14 13 12 11 10

WET-BULB ºF

57 58 59 60 61 62 63 64 65 66 67 68 69 70

1. DETERMINE THE DESIRED DT — MEASURE ENTERING AIR

TEMPERATURE USING DRY BULB (A) AND WET BULB (B). DT IS THE INTERSECTING VALUE OF A AND B IN THE TABLE (SEE TRIANGLE).

2. FIND TEMPERATURE DROP ACROSS COIL

THE DRY BULB AIR TEMPERATURE ENTERING AND LEAV ING THE COIL (A AND C). TEMPERATURE DROP FORMULA:

) = A MINUS C.

DROP

3. DETERMINE IF FAN NEEDS ADJUSTMENT — IF THE DIF

FERENCE BETWEEN THE MEASURED T SIRED DT (T NEEDED. SEE EXAMPLE AT LEFT:

4. ADJUST THE FAN SPEED — SEE INDOOR UNIT INSTRUC

TIONS TO INCREASE/DECREASE FAN SPEED.

NOTE - CHANGING AIR FLOW AFFECTS ALL TEMPERA TURES; RECHECK TEMPERATURES TO CONFIRM THAT THE TEMPERATURE DROP AND DT ARE WITHIN +

–DT) IS WITHIN +3º, NO ADJUSTMENT IS

DROP

— MEASURE

AND THE DE

DROP

3º.

Figure 55. Checking Indoor Airflow over Evaporator Coil using Delta-T Chart

XC20

Page 77

Use the WEIGH-IN method for adding initial refrigerant charge, and then use SUBCOOLING method for for verifying refrigerant charge.

WEIGH-IN

64ºF (17.7ºC) and Below

Amount specified

on nameplate

SUBCOOLING

HEATING

SATº LIQº – SCº =

CHARGING METHOD

Adjust amount for variation in line set length and liquid line diameter using table below.

Set Diameter

USE

COOLING

MODE

60ºF

(15ºC)

USE

MODE

Liquid Line

5/16”

3/8”

1/2”

1. THE DIAGNOSTIC SCREEN ON THE THERMOSTAT OR OUTDOOR CONTROL 7-SEGMENT DISPLAY WILL SHOW INDOOR AND OUTDOOR MOTOR CFMS OR RPMS.

2. MEASURE OUTDOOR AMBIENT TEMPERATURE; DETERMINE WHETHER TO USE COOLING MODE OR HEATING MODE TO CHECK CHARGE.

3. CONNECT GAUGE SET.

4. CHECK LIQUID AND VAPOR LINE PRESSURES. COMPARE PRESSURES WITH EITHER HEAT OR COOLING MODE NORMAL OPERATING PRESSURES IN THE APPLICABLE CHARGING STICKER, NORMAL OPERATING PRESSURES, HIGH STAGE.

NOTE DIFFERENCES MAY MEAN IMPROPER CHARGE OR OTHER SYSTEM PROBLEM.

5. SET THERMOSTAT FOR HEAT/COOL DEMAND, DEPENDING ON MODE BEING USED:

USING COOLING MODE — WHEN THE OUTDOOR AMBIENT TEMPERATURE IS 60°F (15°C) AND ABOVE. TARGET

SUBCOOLING VALUES (SECOND STAGE - HIGH CAPACITY) IN APPLICABLE CHARGING STICKER ARE BASED ON 70 TO 80°F (21-27°C) INDOOR RETURN AIR TEMPERATURE; IF NECESSARY, OPERATE HEATING TO REACH THAT TEMPERATURE RANGE; THEN SET THERMOSTAT TO COOLING MODE SETPOINT TO 68ºF (20ºC) WHICH SHOULD CALL FOR SECOND-STAGE (HIGH STAGE) COOLING. WHEN PRESSURES HAVE STABILIZED, CONTINUE WITH STEP 6.

USING HEATING MODE — WHEN THE OUTDOOR AMBIENT TEMPERATURE IS BELOW 60°F (15°C). TARGET

SUBCOOLING VALUES (SECOND-STAGE - HIGH CAPACITY) IN APPLICABLE CHARGING STICKER ARE BASED ON 65-75°F (18-24°C) INDOOR RETURN AIR TEMPERATURE; IF NECESSARY, OPERATE COOLING TO REACH THAT TEMPERATURE RANGE; THEN SET THERMOSTAT TO HEATING MODE SETPOINT TO 77ºF (25ºC) WHICH SHOULD CALL FOR SECOND-STAGE (HIGH STAGE) HEATING. WHEN PRESSURES HAVE STABILIZED, CONTINUE WITH STEP 6.

6. READ THE LIQUID LINE TEMPERATURE; RECORD IN THE LIQº SPACE.

7. READ THE LIQUID LINE PRESSURE; THEN FIND ITS CORRESPONDING TEMPERATURE IN THE TEMPERATURE/ PRESSURE CHART LISTED IN THE APPLICABLE CHARGING STICKER AND RECORD IT IN THE SATº SPACE.

8. SUBTRACT LIQº TEMPERATURE FROM SATº TEMPERATURE TO DETERMINE SUBCOOLING; RECORD IT IN SCº SPACE.

9. COMPARE SCº RESULTS WITH APPLICABLE CHARGING STICKER, BEING SURE TO NOTE ANY ADDITIONAL CHARGE FOR LINE SET AND/OR MATCH-UP.

10. IF SUBCOOLING VALUE IS GREATER THAN SHOWN IN APPLICABLE CHARGING STICKER FOR THE APPLICABLE UNIT, REMOVE REFRIGERANT; IF LESS THAN SHOWN, ADD REFRIGERANT.

11. IF REFRIGERANT IS ADDED OR REMOVED, REPEAT STEPS 6 THROUGH 10 TO VERIFY CHARGE.

12. DISCONNECT GAUGE SET AND RE-INSTALL BOTH THE LIQUID AND SUCTION SERVICE VALVE CAPS.

(ounces per foot)

- THE REFERENCE TABLE IS A GENERAL GUIDE. EXPECT MINOR PRESSURE VARIATIONS. SIGNIFICANT

NOTE - Insulate liquid line when it is routed through areas where the surrounding ambient temperature could become higher than the temperature of the liquid line or when pressure drop is equal

Total charge

HFC-410A

to or greater than 20 psig.

NOTE - The nameplate is shown for illustration purposes only. Go to actual nameplate on outdoor unit for charge information.

Charging Formula for Liquid Line Charge Adjustments

[(Line set oz./ft. x total length)  (factory charge for line set)] = charge adjustment

0.40

0.60

Example: Units are factorycharged for 15 feet (4.6 meters) of 3/8" line set. Factory charge for 3/8" is 0.60 oz/ft x 15 = 9.0 ounces.

1.00

Figure 56. Using HFC-410A Weigh-In Method

CHARGING METHOD

(All charging MUST be performed while system is operating

either at maximum speed or 100% demand.)

Figure 57. Using HFC-410A Subcooling Method - High Speed (High Capacity)

Table 19. HFC-410A Temperature (°F) - Pressure (Psig)

°F Psig °F Psig °F Psig °F Psig °F Psig °F Psig °F Psig °F Psig

32 100.8 48 137.1 63 178.5 79 231.6 94 290.8 11 0 365.0

33 102.9 49 139.6 64 181.6 80 235.3 95 295.1 111 370.0 126 451.8 142 552.3

34 105.0 50 142.2 65 184.3 81 239.0 96 299.4 11 2 375.1 127 457.6 143 559.1

35 107.1 51 144.8 66 187.7 82 242.7 97 303.8 11 3 380.2 128 463.5 144 565.9

36 109.2 52 147.4 67 190.9 83 246.5 98 308.2 11 4 385.4 129 469.5 145 572.8

37 111.4 53 150.1 68 194.1 84 250.3 99 312.7 11 5 390.7 130 475.6 146 579.8

38 113.6 54 152.8 69 197.3 85 254.1 100 317.2 11 6 396.0 131 481.6 147 586.8

39 115.8 55 155.5 70 200.6 86 258.0 101 321.8 11 7 401.3 132 487.8 148 593.8

40 118.0 56 158.2 71 203.9 87 262.0 102 326.4 11 8 406.7 133 494.0 149 601.0

41 120.3 57 161.0 72 207.2 88 266.0 103 331.0 11 9 412.2 134 500.2 150 608.1

42 122.6 58 163.9 73 210.6 89 270.0 104 335.7 120 417.7 135 506.5 151 615.4

43 125.0 59 166.7 74 214.0 90 274.1 105 340.5 121 423.2 136 512.9 152 622.7

44 127.3 60 169.6 75 217.4 91 278.2 106 345.3 122 428.8 137 519.3 153 630.1

45 129.7 61 172.6 76 220.9 92 282.3 107 350.1 123 434.5 138 525.8 154 637.5

46 132.2 62 175.4 77 224.4 93 286.5 108 355.0 124 440.2 139 532.4 155 645.0

47 134.6 78 228.0 109 360.0 140 539.0

125 445.9

141 545.6

XC20

Page 78

XC20 — HFC-410A CHARGING INFORMATION

FOR COMPLETE CHARGING DETAILS, REFER TO THE OUTDOOR UNIT INSTALLATION AND SERVICE PROCEDURE (CORP 1407-L10).

IMPORTANT !

Room thermostat must be turned down at least 5°F from set point so charging occurs with system operating at 100% capacity. Seven-segment display on outdoor control will show outdoor unit running capacity.

The unit is factory‐charged with the amount of HFC-410A refrigerant indicated on the unit rating plate. This charge is based on a matching indoor coil and outdoor coil with 15 feet (4.6 m) line

set. The outdoor unit should be charged during warm weather. However, applications arise in which charging must occur in the colder months. The method of charging is determined by the outdoor ambient temperature. Before charging the unit, determine the liquid line temperature and the outdoor ambient temperature.

Charge Using the Weigh-In Method — Outdoor Temperature < 64ºF (17.7ºC)

If the system is void of refrigerant, or if the outdoor ambient temperature is 64°F (17.7°C) and below, the refrigerant charge should be weighed into the unit. Do this after any leaks have been repaired.

NOTE - See system Installation Instructions to calculate charge required for longer line sets.

1. Recover the refrigerant from the unit.

2. Conduct a leak check, then evacuate the system as shown in the installation instructions.

3. Weigh in the unit nameplate charge. If weighing facilities are not available, or if you are charging the unit during warm weather, follow one of the other procedures outlined below.

Charge Using The Subcooling Method — Outdoor Temperature > 65ºF (18.3ºC)

When the outdoor ambient temperature is 65ºF (18.3ºC) and above, use the subcooling method to charge the unit. It may be necessary to restrict the air flow through the outdoor coil to achieve pressures in the 325-375 psig (2240-2485 kPa) range. These higher pressures are necessary for checking the charge. Block equal sections of air intake panels and move obstructions sideways until the liquid pressure is in the 325-375 psig (2240-2485 kPa) range. See figure 1.

Block coil one side at a time with cardboard/plastic until proper testing pressures are reached.

Figure 1. Blocking Outdoor Coil

CARDBOARD OR PLASTIC SHEET

1. With the manifold gauge connected to the liquid line service port, allow the unit pressures to stabilize, then, use a digital thermometer to record the liquid line temperature.

2. At the same time, record the liquid line pressure reading.

3. Use a temperature/pressure chart for HFC-410A to determine the saturation temperature for the liquid line pressure reading.

4. Subtract the liquid line temperature from the saturation temperature (according to the chart) to determine subcooling (Saturation temperature - Liquid line temperature = Subcooling Value).

5. Compare the subcooling value with those in table 1. If subcooling is greater than shown, recover some refrigerant. If subcooling is less than shown, add refrigerant.

Charge Using Normal Operating Pressures/Approach or Subcooling Methods

(High Capacity) —Outdoor Temperature >65ºF (18.3ºC) When the outdoor ambient temperature is 65ºF (18.3ºC) and above, use the approach or subcooling methods to charge the system. For best results, indoor temperature should be 70°F (21°C) to 80°F (26°C). Monitor system pressures while charging.

1. Record outdoor ambient temperature using a digital thermometer.

2. Attach high pressure gauge set and operate unit for several minutes to allow system pressures to stabilize.

3. Compare stabilized pressures with those provided in table 3, “Normal Operating Pressures.” Minor variations are to be expected; significant differences could mean that the system is not properly charged or that a problem exists with some component in the system. Pressures higher than those listed indicate that the system is overcharged. Pressures lower than those listed indicate that the system is undercharged. Verify adjusted charge using the approach method.

4. Use the same digital thermometer used to check outdoor ambient temperature to check liquid line temperature. Verify the unit charge using the approach method.

5. The difference between the liquid and ambient temperatures should match values given in table 2. If the values don't agree with the those in table 2, add refrigerant to lower the approach temperature or recover refrigerant from the system to increase the approach temperature.

Using the Normal Operating Pressures Table

Table 3 may be used to help perform maintenance checks. This table is not a procedure for charging the system and any minor variations in the pressures may be expected due to differences in installations. However, significant deviations could mean that the system is not properly charged or that a problem exists with some component in the system.

Charging Temperatures and Pressures – High Speed Only

XC20 Model -024 -036 -048 -060

Table 1 - Subcooling Values (High Capacity)

Saturation Temperature minus Liquid Line Temperature ºF (ºC) + 1ºF (0.5ºC)

Temp. °F (°C)

9 (5) 13 (7.2) 12 (6.7) 7 (3.9)

Table 2 - Approach Values (High Capacity)

Liquid Line Temperature minus Outdoor Ambient Temperature ºF (ºC) + 1ºF (0.5ºC)

Temp. °F (°C)

5 (2.8) 4 (2.2) 6 (3.3) 8 (4.4)

Table 3 - Normal Operating Pressures (Liquid +10 & Suction +5 psig)

Air

Temperature

Entering

Outside Coil

The values below are typical pressures; indoor evaporator match-up, in door air quantity, and evaporator load will cause the pressures to vary.

Liquid Line Pressure / Vapor Line Pressure

65 (18.3) 235 / 139 247 / 141 247 / 137 238 / 133 70 (21.1) 252 / 140 262 / 142 267 / 139 255 / 134 75 (23.9) 272 / 141 284 / 143 288 / 139 274 / 135 80 (26.6) 293 / 142 304 / 144 310 / 140 295 / 136 85 (29.4) 316 / 144 327 / 145 332 / 142 316 / 137 90 (32.2) 340 / 144 350 / 146 358 / 143 338 / 138 95 (35.0) 364 / 145 375 / 147 383 / 143 362 / 139

100 (37.7) 390 / 146 400 / 148 410 / 144 388 / 141 105 (40.6) 417 / 147 426 / 149 437 / 145 415 / 142 110 (43.3) 445 / 149 457 / 150 467 / 146 442 / 143 115 (46.1) 474 / 150 487 / 150 497 / 148 470 / 144

Lennox XC20-036-230-01, XC20-060-230-01, XC20-024-230-01, XC20-048-230-01 Installation And Service Procedure

Specifications and Main Features

Frequently Asked Questions

User Manual