Lennox Elite XC16-024 Installation and operation manual

Page 1 ©2006 Lennox Industries Inc.
Corp. 0625−L5 XC16
Service Literature Revised 07−2006
XC16 SERIES UNITS
The XC16 is a high efficiency residential split−system con-
densing unit, which features a two speed scroll compressor
and R−410A refrigerant. XC16 units are available in 2, 3, 4
and 5 tons. XC16 units are rated for 230 volts only. Applica-
tions where supply voltage is less requires a hard start kit.
The series is designed for use with an expansion valve (ap-
proved for use with R−410A) in the indoor unit. This manual
is divided into sections which discuss the major compo-
nents, refrigerant system, charging procedure, mainte-
nance and operation sequence.
Information contained in this manual is intended for use by
qualified service technicians only. All specifications are sub-
ject to change.
WARNING
Improper installation, adjustment, alteration, service
or maintenance can cause property damage, person-
al injury or loss of life. Installation and service must
be performed by a qualified installer or service
agency.
WARNING
Warranty will be voided if covered equipment is re-
moved from original installation site. Warranty will
not cover damage or defect resulting from:
Flood, wind, lightning, or installation and operation
in a corrosive atmosphere (chlorine, fluorine, salt,
recycled waste water, urine, fertilizers, or other dam-
aging chemicals).
DANGER
Shock Hazard
Remove all power at disconnect
before removing access panel.
Single phase XC16 units use single-
pole contactors. Potential
exists for electrical shock resulting
in injury or death.
Line voltage exist at all components
(even when unit is not in operation).
IMPORTANT
Operating pressures of this R−410A unit are higher
than pressures in R−22 units. Always use service
equipment rated for R410A.
TABLE OF CONTENTS
General Page 1. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Specifications / Electrical Data Page 2. . . . . . . . .
I Application Page 3. . . . . . . . . . . . . . . . . . . . . . . . .
II Unit Components Page 3. . . . . . . . . . . . . . . . . .
III Refrigeration System Page 11. . . . . . . . . . . . . . .
IV Charging Page 12. . . . . . . . . . . . . . . . . . . . . . . . .
V Service and Recovery Page 16. . . . . . . . . . . . . .
VI Maintenance Page 16. . . . . . . . . . . . . . . . . . . . . .
VII Wiring and Sequence of Operation Page 17. .

Page 2
SPECIFICATIONS
General
Dt
Model No. XC16−024 XC16−036 XC16−048 XC16−060
Data Nominal Tonnage 2 345
Connections
(t)
Liquid line (o.d.) − in. 3/8 3/8 3/8 3/8
(sweat) Suction line (o.d.) − in. 3/4 7/8 7/8 1−1/8
Refrigerant 1R−410A charge furnished 7 lbs. 5 oz. 8 lbs. 9 oz. 11 lbs. 4 oz. 14 lbs. 2 oz.
Outdoor
Cil
Net face area − sq. ft. Outer coil 13.22 16.33 21.00 24.93
Coil Inner coil 12.65 15.76 20.27 24.14
Tube diameter − in. 5/16 5/16 5/16 5/16
No. of rows 2 222
Fins per inch 22 22 22 22
Outdoor
F
Diameter − in. 18 22 22 26
Fan No. of blades 3 443
Motor hp 1/10 1/6 1/4 1/3
Cfm 2320 3060 3955 4380
Rpm 1130 845 835 850
Watts 165 215 320 280
Shipping Data − lbs. 1 pkg. 208 238 268 323
ELECTRICAL DATA
Line voltage data − 60hz 4230V−1ph 4230V−1ph 4230V−1ph 4230V−1ph
3Maximum overcurrent protection (amps) 20 35 45 55
2Minimum circuit ampacity 13.6 22.0 28.2 33.9
Compressor Rated load amps 10.3 16.7 21.2 25.6
p
Locked rotor amps 52 82 96 118
Power factor 0.98 0.99 0.99 0.99
Outdoor Fan
Mt
Full load amps 0.7 1.1 1.7 1.8
Motor Locked Rotor amps 2 2.1 3.1 2.9
OPTIONAL ACCESSORIES − must be ordered extra
Compressor Hard Start Kit 10J42  
p
81J69  
Compressor Low Ambient Cut−Off 45F08    
Compressor Time−Off Control 47J27    
Freezestat 3/8 in. tubing 93G35    
5/8 in. tubing 50A93    
Indoor Blower Relay 40K58    
Low Ambient Kit 68M04    
SignatureStattHome Comfort Control 81M27    
Refrigerant
Line Sets
L15−41−20
L15−41−30
L15−65−40
L15−65−50

L15−65−30
L15−65−40
L15−65−50
 
Field Fabricate 
Time Delay Relay 58M81    
NOTE − Extremes of operating range are plus 10% and minus 5% of line voltage.
1Refrigerant charge sufficient for 15 ft. length of refrigerant lines.
2Refer to National or Canadian Electrical Code manual to determine wire, fuse and disconnect size requirements.
3HACR type breaker or fuse.
4Hard start kit is required in applications where the supply voltage is less than 230V.

Page 3
I − APPLICATION
XC16 condensing units are available in 2, 3, 4 and 5 ton capac-
ities. All major components (indoor blower and coil) must be
matched according to Lennox recommendations for the com-
pressor to be covered under warranty. Refer to the Engineer-
ing Handbook for approved system matchups.
II − UNIT COMPONENTS
Unit components are illustrated in figure 1.
XC16 PARTS ARRANGEMENT
FIGURE 1
DUAL CAPACITOR
CONTACTOR
OUTDOOR FAN
COMPRESSOR
HIGH
PRESSURE
SWITCH
FILTER DRIER
LOW
PRESSURE
SWITCH
CAUTION
To prevent personal injury, or damage to panels, unit
or structure, be sure to observe the following:
While installing or servicing this unit, carefully stow
all removed panels out of the way, so that the panels
will not cause injury to personnel, nor cause damage
to objects or structures nearby, nor will the panels be
subjected to damage (e.g., being bent or scratched).
While handling or stowing the panels, consider any
weather conditions, especially windy conditions, that
may cause panels to be blown around and battered.
Remove the louvered panels as follows:
1 − Remove 2 screws, allowing the panel to swing open
slightly (see figure 2).
Detail
A
Detail C
Detail
B
FIGURE 2
Removing/Installing Louvered Panels
MAINTAIN MINIMUM PANEL ANGLE (AS CLOSE TO PARALLEL WITH THE UNIT
AS POSSIBLE) WHILE INSTALLING PANEL.
PREFERRED ANGLE
FOR INSTALLATION
Detail D
ROTATE IN THIS DIRECTION;
THEN DOWN TO REMOVE PANEL
SCREW
HOLES
ANGLE MAY BE TOO
EXTREME
HOLD DOOR FIRMLY TO THE HINGED
SIDE TO MAINTAIN
FULLY−ENGAGED TABS
LIP
IMPORTANT! Do not allow panels to hang on unit by top tab. Tab
is for 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.
2 − Hold the panel firmly throughout this procedure. Ro-
tate bottom corner of panel away from hinge corner post
until lower 3 tabs clear the slots (see figure 2, Detail B).
3 − Move panel down until lip of upper tab clears the top slot
in corner post (see figure 2, Detail A).

Page 4
Position and Install PanelPosition the panel almost par-
allel with the unit (figure 2, Detail D) with the screw side" as
close to the unit as possible. Then, in a continuous motion:
Slightly rotate and guide the lip of top tab inward (figure 2,
Details A and C); then upward into the top slot of the
hinge corner post.
Rotate panel to vertical to fully engage all tabs.
Holding the panel’s hinged side firmly in place, close the
right−hand side of the panel, aligning the screw holes.
When panel is correctly positioned and aligned, insert the
screws and tighten.
A − Control Box (Figure 3)
XC16 units are not equipped with a 24V transformer. All 24
VAC controls are powered by the indoor unit. Refer to wir-
ing diagram.
Electrical openings are provided under the control box cov-
er. Field thermostat wiring is made to color-coded pigtail
connections.
ELECTROSTATIC DISCHARGE (ESD)
Precautions and Procedures
CAUTION
Electrostatic discharge can affect electronic com-
ponents. Take precautions 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 con-
trol and the technician at the same electrostatic po-
tential. Neutralize electrostatic charge by touching
hand and all tools on an unpainted unit surface be-
fore performing any service procedure.
FIGURE 3
DUAL CAPACITOR
(C12)
COMPRESSOR
CONTACTOR
(K1)
CONTROL BOX
GROUNDING
LUG
TIMED OFF
CONTROL.
(OPTION)
1 − Compressor Contactor (K1)
The compressor is energized by a single−pole contactor lo-
cated in the control box. See figure 3. K1 is energized by the
indoor thermostat terminal Y1 (24V) when thermostat de-
mand is present.
2 − Dual Capacitor (C12)
The compressor and fan in XC16 series units use perma-
nent split capacitor motors. The capacitor is located in-
side the unit control box (see figure 3). A single dual" ca-
pacitor (C12) is used for both the fan motor and the com-
pressor (see unit wiring diagram). The fan side and the
compressor side of the capacitor have different MFD rat-
ings. See side of capacitor for ratings.
3 − Start Kit (option)
The start kit consists of a potential relay K31 and start capac-
itor C7. The potential relay controls the operation of the
starting circuit. The relay is normally closed when contactor
K1 is de−energized. When K1 is energized, the compressor
immediately begins start up. K31 remains closed during
compressor start up and and start capacitor C7 remains in
the circuit. When compressor reaches approximately 75%
of its speed, K31 is energized. When K31 energizes, the
contacts open and start capacitor C7 is taken out of the cir-
cuit.
4 − Timed Off Control TOC (option)
The time delay is electrically connected between thermostat
terminal Y and the compressor contactor. Between cycles,
the compressor contactor is delayed for 5 minutes ±2 min-
utes but may last as long as 8 minutes. At the end of the
delay, the compressor is allowed to energize. When thermo-
stat demand is satisfied, the time delay opens the circuit to
the compressor contactor coil and the compressor is de−en-
ergized.

Page 5
B − Two−Stage Scroll Compressor (B1)
CAUTION
In order to avoid injury, take precaution when
lifting heavy objects.
FIGURE 1
TWO−STAGE MODULATED SCROLL
solenoid actuator coil
slider ring
The scroll compressor design is simple, efficient and re-
quires few moving parts. A cutaway diagram of the scroll
compressor is shown in figure 1.The scrolls are located in
the top of the compressor can and the motor is located just
below. The oil level is immediately below the motor.
The scroll is a simple compression concept centered around
the unique spiral shape of the scroll and its inherent proper-
ties. Figure 2 shows the basic scroll form. Two identical
scrolls are mated together forming concentric spiral shapes
(figure 3 ). One scroll remains stationary, while the other is
allowed to orbit" (figure 4). Note that the orbiting scroll does
not rotate or turn but merely orbits" the stationary scroll.
FIGURE 2
SCROLL FORM
FIGURE 3
STATIONARY
SCROLL
ORBITING SCROLL
DISCHARGE
SUCTION
CROSS−SECTION OF SCROLLS
TIPS SEALED BY
DISCHARGE PRESSURE
DISCHARGE
PRESSURE
The counterclockwise orbiting scroll draws gas into the outer
crescent shaped gas pocket created by the two scrolls (figure
4 − 1). The centrifugal action of the orbiting scroll seals off the
flanks of the scrolls (figure 4 − 2). As the orbiting motion con-
tinues, the gas is forced toward the center of the scroll and the
gas pocket becomes compressed (figure 4 −3). When the
compressed gas reaches the center, it is discharged vertical-
ly into a chamber and discharge port in the top of the com-
pressor (figure1). The discharge pressure forcing down on
the top scroll helps seal off the upper and lower edges (tips) of
the scrolls (figure 3 ). During a single orbit, several pockets of
gas are compressed simultaneously providing smooth con-
tinuous compression.
The scroll compressor is tolerant to the effects of liquid re-
turn. If liquid enters the scrolls, the orbiting scroll is allowed
to separate from the stationary scroll. The liquid is worked
toward the center of the scroll and is discharged. If the com-
pressor is replaced, conventional Lennox cleanup practices
must be used.
Due to its efficiency, the scroll compressor is capable of
drawing a much deeper vacuum than reciprocating com-
pressors. Deep vacuum operation can cause internal fusite
arcing resulting in damaged internal parts and will result in
compressor failure. This type of damage can be detected
and will result in denial of warranty claims. The scroll com-
pressor can be used to pump down refrigerant as long as
the pressure is not reduced below 7 psig.
The scroll compressors in all XC16 model units are de-
signed for use with R410A refrigerant and operation at high
pressures. Compressors are shipped from the factory with
3MA (32MMMA) P.O.E. oil. See electrical section in this
manual for compressor specifications.
NOTE − During operation, the head of a scroll compressor
may be hot since it is in constant contact with discharge
gas.

Page 6
TWO−STAGE OPERATION
NOTE − During operation, the head of a scroll compressor
may be hot since it is in constant contact with discharge
gas.
The two−stage scroll compressor operates like any standard
scroll compressor with the exception the two−stage com-
pressor modulates between first stage (low capacity
approximately 67%) and second stage (high capacity).
Modulation occurs when gas is bypassed through bypass
ports (figure 5 bypass ports open) in the first suction pocket.
This bypassing of gas allows the compressor to operate on
first stage (low capacity) if thermostat demand allows. In-
door thermostat setting will determine first or second stage
operation. The compressor will operate on first−stage until
demand is satisfied or the indoor temperature reaches the
thermostat set point calling for second−stage.
Second−stage (high capacity) is achieved by blocking the
bypass ports (figure 5 bypass ports closed) with a slider ring.
The slider ring begins in the open position and is controlled
by a 24VDC internal solenoid. On a Y2 call the internal sole-
noid closes the slider ring, blocking the bypass ports and
bringing the compressor to high capacity. Two−stage modu-
lation can occur during a single thermostat demand as the
motor runs continuously while the compressor modulates
from first−stage to second− stage.
FIGURE 4
SCROLL
HOW A SCROLL WORKS
SUCTION SUCTION
SUCTION
MOVEMENT OF ORBIT
STATIONARY SCROLL
ORBITING
CRESCENT
SHAPED GAS
POCKET
HIGH
PRESSURE
GAS
DISCHARGE
POCKET
FLANKS
SEALED BY
CENTRIFUGAL
FORCE
12
34
SUCTION
INTERMEDIATE
PRESSURE
GAS
SUCTION
POCKET
FIGURE 5
Bypass Ports
Closed
High Capacity
Bypass Ports
Open
67% Capacity
TWO STAGE MODULATION

Page 7
INTERNAL SOLENOID (L34)
The internal unloader solenoid controls the two−stage op-
eration of the compressor by shifting a slide ring mechanism
to open two by−pass ports in the first compression pocket of
the scrolls in the compressor. The internal solenoid is acti-
vated by a 24 volt direct current solenoid coil. The coil
power requires 20VAC. The internal wires from the solenoid
in the compressor are routed to a 2 pin fusite connection on
the side of the compressor shell. The external electrical con-
nection is made to the compressor with a molded plug as-
sembly. This plug contains a full wave rectifier that converts
24 volt AC into 24 volt DC power to power the unloader sole-
noid. Refer to unit diagram for internal circuitry view of plug).
If it is suspect the unloader is not operating properly, check
the following
IMPORTANT
This performance check is ONLY valid on systems
that have clean indoor and outdoor coils, proper air-
flow over coils, and correct system refrigerant
charge. All components in the system must be func-
tioning proper to correctly perform compressor mod-
ulation operational check. (Accurate measurements
are critical to this test as indoor system loading and
outdoor ambient can affect variations between low
and high capacity readings).
STEP 1 Confirm low to high capacity compressor op-
eration
Tools required
Refrigeration gauge set
Digital volt/amp meter
Electronic temperature thermometer
On-off toggle switch
Procedure
1 − Turn main power "OFF" to outdoor unit.
2 − Adjust room thermostat set point above (heating opera-
tion on heat pump) or below (cooling operation) the
room temperature 5ºF.
3 − Remove control access panel. Install refrigeration
gauges on unit. Attach the amp meter to the common
(black wire) wire of the compressor harness. Attach
thermometer to discharge line as close as possible to
the compressor.
4 − Turn toggle switch "OFF" and install switch in series with
Y2 wire from room thermostat.
5 − Cycle main power "ON."
6 − Allow pressures and temperatures to stabilize before
taking any measured reading (may take up to 10 min-
utes).
NOTE − Block outdoor coil to maintain a minimum of 375 psig
during testing).
7 − Record all of the readings for the Y1 demand on table 1.
8 − Close switch to energize Y2 demand.
9 − Allow pressures and temperatures to stabilize before
taking any measured reading (this may take up to 10
minutes).
10 − Record all of the readings of Y2 demand on table 1.
NOTE − On new installations or installations that have
shut down for an extended period of time, if the compres-
sor does not cycle from low stage to high stage on the
first attempt, it may be necessary to recycle the compres-
sor back down to low stage and back up to high stage a
few times in order to get the bypass seals to properly seat
Compare Y1 readings with Y2 readings in table 1. Some
readings should be higher, lower or the same. If the read-
ings follow what table 1 specifies, the compressor is oper-
ating and shifting to high capacity as designed. If the
readings do not follow what table 1 specifies, continue to
step 2 to determine if problem is with external solenoid
plug power.

Page 8
TABLE 1
Unit Readings
Cooling Operation
U
n
it
R
ea
di
ngs Y1 − 1st-Stage Expected Results Y2 − 2nd-Stage
Compressor
Voltage Same
Amperage Higher
Condenser Fan motor
Amperage Same or Higher
Temperature
Ambient Same
Outdoor Coil Discharge Air Higher
Compressor Discharge Line Higher
Indoor Return Air Same
Indoor Coil Discharge Air Lower
Pressures
Suction (Vapor) Lower
Liquid Higher
STEP 2 Confirm DC voltage output on compressor
solenoid plug
11 − Shut power off to outdoor unit.
12 − Supply 24 volts AC control voltage to the wire ends of
the full wave rectifier plug. Listen for a click" as the sole-
noid is energized. See figure 6.
compressor
solenoid fusite
terminals
compressor
fusite
terminals meter
rectifier plug leads apply 24vac
FIGURE 6
13 − Unplug the full wave rectifier plug from the fusite con-
nection on the compressor.
14 − Turn the low voltage power back onto the unit. Supply
24VAC to the wires of the full wave rectifier plug. Set volt
meter to DC volts and measure the DC voltage at the fe-
male connector end of the full wave rectifier plug. The
DC voltage reading should be 1.5 to 3 volts lower than
the input voltage to the plug wire leads. (EX: Input volt-
age is 24VAC output voltage is 22VDC). See figure 7.
meter
rectifier plug leads
compressor
fusite
terminals
solenoid
fusite
terminals
compressor
apply 24vac
FIGURE 7
If the above checks verify that the solenoid plug is provid-
ing power to cycle into high capacity operation, continue
to step 3 to determine if problem is with solenoid coil in
compressor
STEP 3 Confirm internal unloader solenoid has prop-
er resistance
15 − Shut all power off to unit (main and low voltage)
16 − Unplug the molded plug from the compressor solenoid
2−pin fusite.
17 − Using a volt meter set on the 200 ohm scale
meter
rectifier plug leads
compressor
fusite
terminals
solenoid
fusite
terminals
compressor
FIGURE 8
Replace the Compressor under these conditions:
Bad Solenoid
a. Measure the resistance at the 2−pin fusite. See figure 8.
The resistance should be 32 to 60 ohms depending on
compressor temperature. If no resistance replace com-
pressor.
b. Measure the resistance from each fusite pin to ground.
There should not be continuity to ground. If solenoid coil
is grounded, replace compressor.
Good Solenoid
a. Seals not shifting, replace compressor
b. Slider ring not shifting, replace compressor.

Page 9
C − Drier
A filter drier designed for all XC16 model units is factory
installed in the liquid line. The filter drier is designed to re-
move moisture and foreign matter, which can lead to com-
pressor failure.
Moisture and / or Acid Check
Because POE oils absorb moisture, the dryness of the
system must be verified any time the refrigerant system
is exposed to open air. A compressor oil sample must be
taken to determine if excessive moisture has been
introduced to the oil. Table 2 lists kits available from Lennox
to check POE oils.
If oil sample taken from a system that has been exposed to
open air does not test in the dry color range, the filter drier
MUST be replaced.
IMPORTANT
Replacement filter drier MUST be approved for
R−410A refrigerant and POE application.
Foreign Matter Check
It is recommended that a liquid line filter drier be replaced
when the pressure drop across the filter drier is greater than
4 psig.
TABLE 2
KIT CONTENTS TUBE SHELF LIFE
10N46 − Refrigerant Analysis Checkmate−RT700
10N45 − Acid Test Tubes Checkmate−RT750A (three pack) 2 − 3 years @ room temperature. 3+
years refrigerated
10N44 − Moisture Test Tubes Checkmate − RT751 Tubes (three
pack)
6 − 12 months @ room temperature. 2
years refrigerated
74N40 − Easy Oil Test Tubes Checkmate − RT752C Tubes (three
pack)
2 − 3 years @ room temperature. 3+
years refrigerated
74N39 − Acid Test Kit Sporlan One Shot − TA−1
FIGURE 9
1− Shut off power to unit.
2− Remove high pressure switch from fitting next to filter drier.
(A schrader core is located under the high pressure switch).
3− Install high pressure gauge hose onto high pressure switch fitting.
4− Turn power on to unit and turn room thermostat to call for cooling.
5− Record pressure reading on gauge.
6− Remove hose from high pressure fitting and install on liquid line valve.
7− Read liquid line valve pressure.
8− High pressure fitting pressure − liquid line valve pressure = filter drier
pressure drop.
9− If pressure drop is greater than 4 psig replace filter drier. See figure 10.
10− Re−install high pressure switch.
MEASURING FILTER DRIER PRESSURE DROP
FIGURE 10
REPLACING FILTER DRIER
1− Recover all refrigerant from unit.
2− Remove original filter drier.
3− Install new filter drier in existing location or alternate location as
shown. Proper brazing procedures should be followed.
4− Evacuate system. See section IV − part B − .
5− Recharge system. See section IV − part C − .

Page 10
D − Condenser Fan Motor (B4)
All units use single−phase PSC fan motors which require a run
capacitor. In all units, the condenser fan is controlled by
the compressor contactor.
ELECTRICAL DATA tables in this manual show specifi-
cations for condenser fans used in XC16’s.
Access to the condenser fan motor on all units is gained
by removing the four screws securing the fan assembly.
See figure 4. The grill fan assembly can be removed from
the cabinet as one piece. See figure 5. The condenser fan
motor is removed from the fan guard by removing the four
nuts found on top of the grill. See figure 5 if condenser fan
motor replacement is necessary.
Make sure all power is disconnected before
beginning electrical service procedures.
DANGER
FIGURE 4
Remove
screws
Remove
screws
ALIGN FAN HUB FLUSH WITH END OF SHAFT
FIGURE 5
E − Low Pressure Switch (S87)
All XC16 units are equipped with an auto-reset, single-pole/
single-throw low pressure switch is located in the vapor line.
This switch shuts off the compressor by de−energizing K1
when vapor line pressure drops below the factory setting.
The switch is closed during normal operating pressure con-
ditions and is permanently adjusted to trip (open) at 40 + 5
psi. The switch automatically resets when vapor line pres-
sure rises above 90 + 5 psi.
F − High Pressure Switch (S4)
XC16 units are equipped with a high pressure switch that is
located in the liquid line of the compressor. The switch
(SPST, manual reset, normally closed) removes power from
the compressor contactor control circuit when discharge
pressure rises above factory setting at 590 + 10 psi.
G − Crankcase Heater (HR1) &
Thermostat (S40) −048 and −060 units only
Compressor in the XC16−048 and −060 units are equipped
with a 70 watt, belly band type crankcase heater. HR1 pre-
vents liquid from accumulating in the compressor. HR1 is
controlled by a thermostat located on the liquid line. When liq-
uid line temperature drops below 50° F the thermostat closes
energizing HR1. The thermostat will open, de−energizing
HR1 once liquid line temperature reaches 70° F .