Lennox XP19-024, XP19-036, XP19-048, XP19-060 Instruction Manual

Page 1
© 2005 Lennox Industries Inc.
Corp. 0510−L4
XP19
Service Literature
Revised 06−2008
The XP19 is a high efficiency residential split−system heat pump unit, which features a two−step scroll compressor and R410A refrigerant. XP19 units are available in 2, 3 , 4 and 5 ton sizes. The series is designed for use with an ex­pansion valve only (approved for use with R410A) in the in­door unit. This manual is divided into sections which dis­cuss the major components, refrigerant system, charging procedure, maintenance and operation sequence. Information contained in this manual is intended for use by qualified service technicians only. All specifications are subject to change.
CAUTION
Physical contact with metal edges and corners while applying excessive force or rapid motion can result in personal injury. Be aware of, and use caution when working nearby these areas during installation or while servicing this equipment.
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.
WARNING
Improper installation, adjustment, alteration, service or maintenance can cause property damage, person­al injury or loss of life. Installation and service must be performed by a qualified installer or service agency.
DANGER
Shock Hazard Remove all power at disconnect be-
fore removing access panel. XP19 units use single-pole contac­tors. Potential exists for electrical shock resulting in injury or death. Line voltage exists at all components (even when unit is not in operation).
Table of Contents
General 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Specifications / Electrical Data 2. . . . . . . . . . . . . . . . . .
I Application 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
II Unit Components 3. . . . . . . . . . . . . . . . . . . . . . . . . . . .
III Refrigerant System 18. . . . . . . . . . . . . . . . . . . . . . . . . .
IV Charging 20. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
V Service and Recovery 24. . . . . . . . . . . . . . . . . . . . . . . .
VI Maintenance 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VIIBrazing Procedure 24. . . . . . . . . . . . . . . . . . . . . . . . . .
VIII Diagrams and Operating Sequence 25. . . . . . . . . .
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SPECIFICATIONS
General
Model No. XP19−024 XP19−036 XP19−048 XP19−060
Data
Nominal Tonnage (kW) 2 (7.0)
3 (10.6) 4 (14.1) 5 (17.6)
Connections
Liquid line (o.d.) − in. (mm) 3/8 (9.5) 3/8 (9.5) 3/8 (9.5) 3/8 (9.5)
(sweat)
Vapor line (o.d.) − in. (mm) 7/8 (22.2)
7/8 (22.2) 7/8 (22.2) 1−1/8 (28.6)
Refrigerant
1
R−410A charge furnished 12 lbs. 0 oz. (5.4
kg)
12 lbs. 5 oz. (5.6
kg)
13 lbs. 8 oz. (6.1
kg)
16 lbs. 5 oz. (7.4
kg)
Outdoor
Net face area − sq. ft. (m2) Outer coil 20.50 (1.90) 20.50 (1.90) 26.92 (2.50) 26.92 (2.50)
Coil
Inner coil 19.86 (1.85)
19.86 (1.85) 26.07 (2.42) 26.07 (2.42)
Tube diameter − in. (mm) 5/16 (0.52) 5/16 (0.52) 5/16 (0.52) 5/16 (0.52)
No. of rows 2 2 2 2
Fins per inch (m) 22 (866) 22 (866) 22 (866) 22 (866)
Outdoor
Diameter − in. (mm) 26 (660) 26 (660) 26 (660) 26 (660)
Fan
No. of blades 3
3 3 3
Motor hp (W) 1/3 (249) 1/3 (249) 1/3 (249) 1/3 (249)
Cfm (L/s) 1st stage 2500 (1180) 2500 (1180) 2800 (1320) 2800 (1320)
2nd stage 2500 (1180) 2800 (1320) 3400 (1605) 3400 (1605)
Rpm − 1st stage 700 700 700 700
2nd stage 700 820 820 820
Watts − 1st stage 70 70 150 150
2nd stage 70 105 220 220
Shipping Data − lbs. (kg) 1 pkg. 304 (138) 315 (143) 352 (160) 387 (176)
ELECTRICAL DATA
Line voltage data − 60hz 208/230V−1ph 208/230V−1ph 208/230V−1ph 208/230V−1ph
3
Maximum overcurrent protection (amps) 25 40 50 60
2
Minimum circuit ampacity 15.7 23.7 29.3 34.9
Compressor
Rated load amps 10.3 16.7 21.2 25.7
p
Locked rotor amps 52 82 96 118
Power factor 0.98 0.98 0.98 0.98
Outdoor Coil Fan Motor
Full load amps 2.8 2.8 2.8 2.8
OPTIONAL ACCESSORIES − must be ordered extra
Compressor Hard Start Kit
10J42
p
81J69
Compressor Low Ambient Cut−Off 45F08
Freezestat
3/8 in. tubing 93G35
1/2 in. tubing 39H29
5/8 in. tubing 50A93
Indoor Blower Relay 40K58
Low Ambient Kit 68M04
Monitor Kit − Service Light 76F53
Mounting Base 69J07
Outdoor
Thermostat 56A87
Thermostat
Mounting Box − US 31461
Kit
Canada 33A09
SignatureStatt Home Comfort Control 81M28
Refrigerant Line Sets
L15−65−15 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.
1
Refrigerant charge sufficient for 15 ft. (4.6 m) length of refrigerant lines.
2
Refer to National or Canadian Electrical Code manual to determine wire, fuse and disconnect size requirements.
3
HACR type breaker or fuse.
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I−APPLICATION
All major components (indoor blower and coil) must be matched according to Lennox recommendations for the compressor to be covered under warranty. Refer to the En­gineering Handbook for approved system matchups. A misapplied system will cause erratic operation and can re­sult in early compressor failure.
II−Unit Components
Remove 4 screws to remove panel for accessing compressor and controls.
Install by positioning panel with holes aligned; install screws and tighten.
FIGURE 1
Access Panel
Removing Access Panels
Remove and reinstall the access panel as described in fig­ure 1.
Remove the louvered panels as follows:
1−. Remove 2 screws, allowing the panel to swing open
slightly.
2−. Hold the panel firmly throughout this procedure.
Rotate 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).
Position and Install PanelPosition the panel almost parallel 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.
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.
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FIGURE 3
XP19 PARTS ARRANGEMENT
OUTDOOR FAN
COMPRESSOR
CONTACTOR
DEFROST
CONTROL
LSOM
LOW PRESSURE
SWITCH
HIGH PRESSURE
SWITCH
DRIER
REVERSING
VALV E
CAPACITOR
ELECTROSTATIC DISCHARGE (ESD)
Precautions and Procedures
CAUTION
Electrostatic discharge can affect electronic components. 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 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.
A−Two−Stage Scroll Compressor (B1)
The scroll compressor design is simple, efficient and re­quires 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 properties. Figure 5 shows the basic scroll form. Two iden­tical scrolls are mated together forming concentric spiral shapes (figure 6). One scroll remains stationary, while the other is allowed to orbit" (figure 7). Note that the orbiting scroll does not rotate or turn but merely orbits" the station­ary scroll.
FIGURE 4
TWO−STAGE MODULATED SCROLL
slider ring
solenoid actuator coil
FIGURE 5
SCROLL FORM
FIGURE 6
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 7 − 1). The centrifugal action of the orbiting scroll seals off the flanks of the scrolls (figure 7 − 2). As the orbiting motion continues, the gas is forced toward the center of the scroll and the gas pocket becomes compressed (figure 7
−3). When the compressed gas reaches the center, it is dis­charged vertically into a chamber and discharge port in the top of the compressor (figure 7 − 4). The discharge pressure forcing down on the top scroll helps seal off the upper and lower edges (tips) of the scrolls (figure 6). During a single or­bit, several pockets of gas are compressed simultaneously providing smooth continuous compression.
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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.
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.
NOTE − During operation, the head of a scroll compressor may be hot since it is in constant contact with discharge gas.
The scroll compressors in all XP19 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.
TWO−STAGE OPERATION
The two−stage scroll compressor operates like any stan­dard scroll compressor with the exception the two−stage compressor modulates between first stage (low capacity approximately 67%) and second stage (high capacity). Modulation occurs when gas is bypassed through bypass ports (figure 8 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. Indoor 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 8 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 inter- nal solenoid closes the slider ring, blocking the bypass ports and bringing the compressor to high capacity. Two− stage modulation can occur during a single thermostat de­mand as the motor runs continuously while the compressor modulates from first−stage to second− stage.
FIGURE 7
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
3
4
SUCTION
INTERMEDIATE
PRESSURE
GAS
SUCTION
POCKET
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FIGURE 8
Bypass Ports
Closed
High Capacity
Bypass Ports
Open
Low Capacity
TWO−STAGE MODULATION
INTERNAL SOLENOID (L34)
The internal unloader solenoid controls the two−stage op-
eration of the compressor by shifting a slide ring mecha-
nism to open (low capacity) or close (high capacity), two
by−pass ports in the first compression pocket of the scrolls
in the compressor. The internal solenoid is activated by a
24 volt direct current solenoid coil. 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 connection is made to the compressor
with a molded plug assembly. The molded plug receives 24
volt DC power from the LSOM II.
If it is suspected 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 air­flow over coils, and correct system refrigerant charge. All components in the system must be func­tioning proper to correctly perform compressor modulation 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 operation
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 op-
eration 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 min­utes).
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 com­pressor does not cycle from low stage to high stage on the first attempt, it may be necessary to recycle the com­pressor 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 readings follow what table 1 specifies, the compressor is operating and shifting to high capacity as designed. If the readings do not follow what table1 specifies, continue to step 2 to determine if problem is with external solenoid plug power.
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TABLE 1
Compressor Operation
Unit Readings
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 in Cooling
Lower in Heating
Compressor Discharge Line Higher Indoor Return Air Same Indoor Coil Discharge Air Lower in Cooling
Higher in Heating
Pressures
Suction (Vapor) Lower Liquid Higher
STEP 2 Confirm DC voltage output on compressor solenoid plug
1−. Shut power off to the outdoor unit.
2−. Insert lead wires from voltmeter into back of the red
and black wire plug jack that feeds power to compres­sor solenoid coil. Set voltmeter to DC volt scale to read DC voltage output from LSOM II plug. See figure 9.
FIGURE 9
3−. Apply a Y1 and Y2 demand from the indoor thermostat
to the LSOM II.
4−. Turn power back on to unit.
5−. Compressor should cycle ON" when Y1 is calling.
6−. With Y2 calling, 5 seconds after compressor cycles
ON", LSOM II will output 24 volt DC signal to the com­pressor solenoid plug. Once the solenoid has pulled in, the LSOM II will reduce the DC voltage to a pulsating 6 to 18 volt DC output to the solenoid to allow the sole­noid to remain energized.
IMPORTANT
When checking compressor for two−stage operation, always cycle Y1 to Y2 from terminals on the LSOMII or room thermostat connections. DO NOT cycle sec­ond stage (Y2) of compressor by unplugging the 24VDC solenoid LSOM II end of plug. The LSOM II will only output a 6 to 18VDC signal which will be insuffi­cient voltage to pull the solenoid coil in for second stage.
If compressor solenoid is still not shifting to high capac­ity, this check will verify that DC power is being fed from the LSOM II.
7−. Shut power off to unit (main and low voltage)
8−. Unplug the 2 pin solenoid plug from the fusite connec-
tion on the compressor and the plug end from the LSOM II.
9−. Using an OHM meter, check for continuity on the plug
harness wire ends (red to red, black to black). Wires should have continuity between same colors and no continuity between opposite color wires.
If the above checks verify that the solenoid plug is pro­viding 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
proper resistance
1−. Shut all power off to unit (main and low voltage)
2−. Unplug the molded plug from the compressor solenoid
2−pin fusite.
3−. Using a volt meter set on the 200 ohm scale
Replace the Compressor under these conditions:
Page 8
Bad Solenoid
a. Measure the resistance at the 2−pin fusite. The resist­ance should be 32 to 60 ohms depending on compressor temperature. If no resistance replace compressor.
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.
B−Contactor (K1)
The compressor is energized by a contactor located in the control box. All XP19 units are single phase and use single− pole contactors.
C−Low Pressure Switch (S87)
The XP19 is equipped with an auto−reset low pressure switch which is located on the suction line. The switch shuts off the compressor when the suction pressure falls below the factory setting. This switch is ignored during the first 90 seconds of compressor start up, during defrost operation, 90 seconds after defrost operation, during test mode and when the outdoor temperature drops below 15°F.
The switch closes when it is exposed to 55 psig and opens at 25 psig. It is not adjustable.
D−High Pressure Switch (S4)
IMPORTANT
Pressure switch settings for R410A refrigerant will be significantly higher than units with R22.
An auto-reset, single-pole/single-throw high pressure switch is located in the liquid line. This switch shuts off the compres­sor when liquid line pressure rises above the factory setting. The switch is normally closed and is permanently adjusted to trip (open) at 590 +
15 psi and close at 418 + 15 psi. See fig-
ure 3 for switch location.
E−Capacitor (C12)
The compressor in XP19−024, −036, −048 and −060 units use a permanent split capacitor (see unit wiring diagram). The capacitor is located inside the unit control box. Ratings are on capacitor side.
F−Condenser Fan with Variable Speed Motor(B4)
The variable speed condenser fan motor (figure 10) used in all units is a three-phase, electronically controlled d.c. brushless motor (controller converts single phase a.c. to three phase d.c.), with a permanent-magnet-type rotor, manufactured by GE. Because this motor has a permanent magnet rotor it does not need brushes like conventional D.C. motors. The motors consist of a control module and motor . Internal components are shown in figure 11. The stator windings are split into three poles which are electrically connected to the controller. This ar­rangement allows motor windings to be turned on and off in sequence by the controller.
The controller is primarily an a.c. to d.c. converter. Con­verted d.c. power is used to drive the motor. The control­ler contains a microprocessor which monitors varying conditions inside the motor (such as motor workload).
The controller uses sensing devices to know what position the rotor is in at any given time. By sensing the position of the rotor and then switching the motor windings on and off in sequence, the rotor shaft turns the blower.
VARIABLE SPEED CONDENSER FAN MOTOR
FIGURE 10
RED
YELLOW
BLACK
RED
BLUE
motor
control module
BLOWER MOTOR COMPONENTS
FIGURE 11
STATOR
(WINDINGS)
OUTPUT
SHAFT
BEARING
ROTOR
Internal Operation
The condenser fan motor is a variable speed motor with RPM settings at 700 (Y1) and 820 (Y2). The variation in speed is accomplished each time the controller switches a stator wind­ing (figure10) on and off, it is called a pulse." The length of time each pulse stays on is called the pulse width." By vary­ing the pulse width the controller varies motor speed (called pulse-width modulation"). This allows for precise control of motor speed and allows the motor to compensate for varying load conditions as sensed by the controller. In this case, the controller monitors the static workload on the motor and var­ies motor rpm in order to maintain constant airflow (cfm).
Motor rpm is continually adjusted internally to maintain constant static pressure against the fan blade. The control­ler monitors the static work load on the motor and motor amp-draw to determine the amount of rpm adjustment. Blower rpm is adjusted internally to maintain a constant cfm. The amount of adjustment is determined by the incre­mental taps which are used and the amount of motor load­ing sensed internally. The motor constantly adjusts rpm to maintain a specified cfm.
Page 9
Initial Power Up
When line voltage is applied to the motor, there will be a large inrush of power lasting less than 1/4 second. This in­rush charges a bank of DC filter capacitors inside the con­troller. If the disconnect switch is bounced when the discon­nect is closed, the disconnect contacts may become welded. Try not to bounce the disconnect switch when ap­plying power to the unit.
The DC filter capacitors inside the controller are connected electrically to the speed tap wires. The capacitors take approximately 5 minutes to discharge when the disconnect is opened. For this reason it is necessary to wait at least 5 minutes after turning off power to the unit before attempting to service motor.
DANGER
Disconnect power from unit and wait at least five minutes to allow capacitors to discharge before attempting to ser­vice motor. Failure to wait may cause personal injury or death.
Motor Start-Up
At start-up, the motor may gently rock back and forth for a moment. This is normal. During this time the electronic controller is determining the exact position of the rotor. Once the motor begins turning, the controller slowly eases the motor up to speed (this is called soft-start"). The motor may take as long as 10-15 seconds to reach full speed. If the motor does not reach 200rpm within 13 seconds, the motor shuts down. Then the motor will im­mediately attempt a restart. The shutdown feature pro­vides protection in case of a frozen bearing or blocked fan blade. The motor may attempt to start eight times. If the motor does not start after the eighth try, the controller locks out. Reset controller by momentarily turning off power to unit.
Troubleshooting
If first or second stage thermostat call for cool is present and the variable speed condenser fan motor does not ener­gize, check voltage at the breaker box. If voltage is present do the following and reference figure 12.
1− Check for 240 volts between the compressor RED wi-
res.
2− Initiate a first stage call for cool. Check for 24 volts be-
tween the fan motor YELLOW wire and fan motor BLACK wire.
3− Initiate a second stage call for cool. Check for 24 volts
between the fan motor YELLOW wire and fan motor BLACK wire, then check for 24 volts between the fan motor BLUE wire and fan motor BLACK.
4− Repeat steps 1 and 2 with a HEAT call.
FIGURE 12
RED
RED
240V
YELLOW
BLUE
BLACK
common
1st Stage (low capacity − 700 rpm)
2nd Stage (High capacity − 820 rpm)
B4
24V
Y1
Y2
RED
RED
YELLOW
BLUE
BLACK
B4
240V
24V
common
Y2
Y1
24V
0V
24V
24V
240V
240V
Page 10
Replacement
See figure 13 if condenser fan motor replacement is nec­essary.
FIGURE 13
A" See Table 2
TABLE 2
XP19 UNIT "A" DIM. + 1/8"
−024, −036 3/4"
−048, −060 Flush
G−Filter Drier
A filter drier designed for all XP19 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.
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 3 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 R410A 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.
H−Accumulator (XP19−060−1 and −2 only)
5 ton XP19−1 and −2 units are equipped with an accumula­tor. The purpose of the accumulator is to trap and evapo­rate all liquid refrigerant returning to the compressor.
TABLE 3
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
Page 11
I−Lennox System Operation Monitor (A132)
The Lennox system operation monitor (LSOM) is a 24 volt powered module, (see diagnostic module A132 on wiring diagram and figure 14) wired directly to the indoor unit. The LSOM is located in the control box and is used to trouble shoot problems in the system. The module has three LED’s for troubleshooting: GREEN indicates power status, YEL­LOW indicates an abnormal condition and RED indicates thermostat demand, but compressor not operating. See table 4 for troubleshooting codes.
The diagnostic indicator detects the most common fault conditions in the heat pump system. When an abnormal condition is detected, the module communicates the spe­cific condition through its ALERT and TRIP lights. The module is capable of detecting both mechanical and elec­trical system problems. See figure 14 for the system opera­tion monitor.
FIGURE 14
Lennox System Operation Monitor
DATA OUTPUT CONNECTOR
.25" SPADE CONNECTOR (5)
SOLENOID CONNECTOR
POWER LED
Y2
Y
L
R
C
ALERT LED
TRIP LED
IMPORTANT − The LSOM is not a safety component and cannot shutdown or control the XP19. The LSOM is a monitoring device only.
LED Functions
Alert LED (green) − Indicates voltage within the range of
19−28VAC is present at the system monitor connections. Alert LED (yellow) − communicates an abnormal system
condition through a unique Flash Code the alert LED flashes a number of times consecutively; then pauses; then repeats the process. This consecutive flashing corre­lates to a particular abnormal condition.
Trip LED (red) − indicates there is a demand signal from the thermostat but no current to the compressor is detected by the module.
Flash code number − corresponds to a number of LED flashes, followed by a pause, and then repeated.
Trip & Alert LEDs flashing simultaneously − indicates that the control circuit voltage is too low for operation. Reset ALERT flash code by removing 24VAC power from moni­tor. Last ALERT flash code will display for 1 minute after monitor is powered on.
Thermostat Second-Stage Cooling
The Lennox system operation monitor (LSOM) requires a two-stage room thermostat to operate properly.
Y2 room thermostat connectionWhile the compressor
is not running, LSOM will not power the solenoid, re­gardless of the state of Y2. If alert codes 1 or 9 (see table 4) appear while the compressor is running, LSOM will turn off the solenoid to prevent solenoid damage from overheating conditions.
L terminal connectionThe L connection is used to com-
municate alert codes to the room thermostat. On se­lected Lennox SignatureStat thermostats, a blinking check" LED will display on the room thermostat and on select White-Rodgers room thermostats, an icon on the display will flash. Either will flash at the same rate as the LSOM yellow alert LED.
NOTE − ROOM THERMOSTAT WITH SERVICE OR CHECK LIGHT FEATURE − The room thermostat may blink the Check" or Service" LED or it may come on solid. Confirm fault by observing and interpreting the code from the LSOM yellow alert LED at the unit.
Y2 DC Solenoid Connector (DC SOL)The 24VDC so-
lenoid, which is internal to the compressor, will not op­erate properly if 24VAC is applied to the compressor solenoid terminals. A voltmeter attached to the DCSOL output will measure 4−18 VDC when the sole­noid is be energized.
Installation verification-LSOMTo verify correct LSOM
installation, two functional tests can be performed. Dis­connect power from the compressor and force a ther­mostat call for cooling. The red trip LED should turn on indicating a compressor trip as long as 24VAC is mea­sured at the Y terminal. If the red LED does not function as described, refer to table 4 to verify the wiring. Dis­connect power from the compressor and 24VAC power from LSOM. Remove the wire from the Y terminal of LSOM and reapply power to the compressor, allowing the compressor to run. The yellow alert LED will begin flashing a code 8 indicating a welded contactor. Dis- connect power from the compressor and 24VAC power from the LSOM. While the LSOM is off, reattach the wire to the Y terminal. Reapply power to the compres­sor and 24VAC power to the LSOM; the yellow alert LED will flash the previous code 8 for one minute and then turn off. If the yellow LED does not function as de­scribed, refer to table 4 to verify the wiring.
Resetting alert codesAlert codes can be reset manual­ly or automatically:
Manual reset: Cycle the 24VAC power to LSOM off and on.
Automatic reset: After an alert is detected, the LSOM con-
tinues to monitor the compressor and system. When/if conditions return to normal, the alert code is turned off automatically.
Page 12
TABLE 4
System Operation Monitor LED Troubleshooting Codes
Status LED Condition Status LED Description Status LED Troubleshooting Information
Green Power" LED ON Module has power 24VAC control power is present at the module terminal.
Green Power" LED OFF
Module not powering up Determine/verify that both R and C module terminals are connected
and voltage is present at both terminals.
Red Trip" LED ON System and compressor
check out OK
1
Verify Y terminal is connected to 24VAC at contactor coil.
2
Verify voltage at contactor coil falls below 0.5VAC when off.
3
Verify 24VAC is present across Y and C when thermostat demand signal is present; if not present, Y and C wires are reversed.
Thermostat demand signal Y1 is present, but compres­sor not running
NOTE − During 5-minute delay in defrost board, the red trip" LED will be on.
1
Compressor protector is open.
2
Outdoor unit power disconnect is open.
3
Compressor circuit breaker or fuse(s) is open.
4
Broken wire or connector is not making contact.
5
Low pressure switch open if present in the system.
6
Compressor contactor has failed to close.
Red Trip" & Yellow Alert" LEDs Flashing
Simultaneous flashing. Indicates that the control circuit voltage is too low for operation.
Yellow Alert" Flash Code 1*
Long Run Time − Compres-
sor is running extremely long run cycles
1
Low refrigerant charge.
2
Evaporator blower is not running.
3
Evaporator coil is frozen.
4
Faulty metering device.
5
Condenser coil is dirty
.
6
Liquid line restriction (filter drier blocked if present)
.
7
Thermostat is malfunctioning
.
Yellow Alert" Flash Code 2*
System Pressure Trip or Discharge Sensor Fault
Discharge or suction pres­sure out of limits or compressor overloaded
1
Check high head pressure or discharge line sensor.
2
Condenser coil poor air circulation (dirty, blocked, damaged).
3
Condenser fan is not running.
4
Return air duct has substantial leakage.
5
If low pressure switch is present, see Flash Code 1 information.
Yellow Alert" Flash Code 3*
Short Cycling − Compres-
sor is running only briefly
1
Thermostat demand signal is intermittent.
2
Time delay relay or control board is defective.
3
If high pressure switch is present, see Flash Code 2 information.
4
If discharge sensor is present, see Flash Code 2 information.
Yellow Alert" Flash Code 4*
Locked Rotor
1
Run capacitor has failed.
2
Low line voltage (contact utility if voltage at disconnect is low).
3
Excessive liquid refrigerant in the compressor.
4
Compressor bearings are seized.
Yellow Alert" Flash Code 5*
Open Circuit
1
Outdoor unit power disconnect is open.
2
Unit circuit breaker or fuse(s) is open.
3
Unit contactor has failed to close.
4
High pressure switch is open and requires manual reset.
5
Open circuit in compressor supply wiring or connections.
6
Unusually long compressor protector reset time due to extreme ambi­ent temperature.
7
Compressor windings are damaged.
Yellow Alert" Flash Code 6*
Open Start Circuit − Cur-
rent only in run circuit
1
Run capacitor has failed.
2
Open circuit in compressor start wiring or connections.
3
Compressor start winding is damaged.
Yellow Alert" Flash Code 7*
Open Run Circuit − Current
only in start circuit
1
Open circuit in compressor start wiring or connections.
2
Compressor start winding is damaged.
Yellow Alert" Flash Code 8*
Welded Contactor − Com-
pressor always runs
1
Compressor contactor failed to open.
2
Thermostat demand signal not connected to module.
Yellow Alert" Flash Code 9*
Low Voltage − Control cir-
cuit <17VAC
1
Control circuit transformer is overloaded.
2
Low line voltage (contact utility if voltage at disconnect is low).
*Flash code number corresponds to a number of LED flashes, followed by a pause, and then repeated. Reset ALERT flash code by removing 24VAC power from monitor; last code will display for 1 minute after monitor is powered on.
Page 13
J−Defrost System
The demand defrost controller measures differential tem­peratures to detect when the system is performing poorly because of ice build−up on the outdoor coil. The controller self−calibrates" when the defrost system starts and after each system defrost cycle. The defrost control board com­ponents are shown in figure 15.
Defrost Control Board
24V TERMINAL STRIP CONNECTIONS
DIAGNOSTIC LEDS
PRESSURE
SWITCH
CIRCUIT
CONNECTIONS
TEST PINS
Note − Component Locations Vary by Board Manufacturer.
SENSOR PLUG IN
(COIL, AMBIENT,
& DISCHARGE-
SENSORS)
FIGURE 15
REVERSING
VALV E
DELAY
PINS
LOW AMBIENT THERMOSTAT PINS
DEFROST
TERMINATION
PIN SETTINGS
The control monitors ambient temperature, outdoor coil temperature, and total run time to determine when a de­frost cycle is required. The coil temperature probe is de­signed with a spring clip to allow mounting to the outside coil tubing. The location of the coil sensor is important for proper defrost operation.
NOTE − The demand defrost board accurately measures the performance of the system as frost accumulates on the outdoor coil. This typically will translate into longer running time between defrost cycles as more frost accumulates on the outdoor coil before the board initiates defrost cycles.
Diagnostic LEDs
The state (Off, On, Flashing) of two LEDs on the defrost board (DS1 [Red] and DS2 [Green]) indicate diagnostics conditions that are described in table 6.
Defrost Board Pressure Switch Connections
The unit’s automatic reset pressure switches (LO PS − S87 and HI PS − S4) are factory−wired into the defrost board on the LO−PS and HI−PS terminals, respectively.
Low Pressure Switch (LO−PS)When the low pressure switch trips, the defrost board will cycle off the compressor, and the strike counter in the board will count one strike. The low pressure switch is ignored under the following condi­tions:
during the defrost cycle and 90 seconds after the termina-
tion of defrost
when the average ambient sensor temperature is below
15° F (−9°C) for 90 seconds following the start up of the compressor during "test" mode High Pressure Switch (HI−PS)When the high pressure
switch trips, the defrost board will cycle off the compressor, and the strike counter in the board will count one strike.
Defrost Board Pressure Switch Settings
High Pressure (auto reset) − trip at 590 psig; reset at 418
psig.
Low Pressure (auto reset) − trip at 25 psig; reset at 40 psig.
5−Strike Lockout Feature
The internal control logic of the board counts the pressure switch trips only while the Y1 (Input) line is active. If a pres­sure switch opens and closes four times during a Y1 (In­put), the control logic will reset the pressure switch trip counter to zero at the end of the Y1 (Input). If the pressure switch opens for a fifth time during the current Y1 (Input), the control will enter a lockout condition.
The 5−strike pressure switch lockout condition can be reset by cycling OFF the 24−volt power to the control board or by shorting the TEST pins between 1 and 2 seconds. All timer functions (run times) will also be reset.
If a pressure switch opens while the Y1 Out line is engaged, a 5−minute short cycle will occur after the switch closes.
Defrost System Sensors
Sensors connect to the defrost board through a field-re­placeable harness assembly that plugs into the board. Through the sensors, the board detects outdoor ambient, coil, and discharge temperature fault conditions. As the de­tected temperature changes, the resistance across the sensor changes. Sensor resistance values can be checked by ohming across pins shown in table 5. The graph in figure 16 shows sensor temperature to resistance range.
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 table 5, 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.
TABLE 5
Sensor Temperature / Resistance Range
Sensor
Temperature Range °F (°C)
Resistance values range (ohms)
Pins/Wire Color
Outdoor −35 (−37) to 120
(48)
280,000 to 3750 3 & 4
(Black)
Coil −35 (−37) to 120
(48)
280,000 to 3750 5 & 6
(Brown)
Discharge (if applicable)
24 (−4) to 350 (176)
41,000 to 103 1 & 2
(Yellow)
Note: Sensor resistance increases as sensed temperature decreases.
Page 14
Ambient and Coil Sensor Discharge Sensor
RESISTANCE (OHMS) RESISTANCE (OHMS)
TEMPERATURE (ºF)
TEMPERATURE (ºF)
5750
7450
9275
11775
15425
19975
26200
34375
46275
62700
200
325
250
425
600
825
1175
1700
2500
3750
5825
100
90
80
70
60
50
40
30
20
10
0
300
280
260
240
220
200
180
160
140
120
100
10000 30000 50000 70000 90000 1000 2000 50004000 60003000
4650
3000
2025
1400
1000
700
225
275
375
500
85300
FIGURE 16
FIGURE 17
Sensor Locations
24 tubes up
(after April
2006)
SLEEVE
AMBIENT SENSOR − Extend tip of plastic sensor just outside of plastic sleeve.
Place ambient sensor and wire from defrost board inside of plastic sleeve and route thru gap between corner post and coil support as shown. Secure with wire tie.
DISCHARGE SENSOR
WIRE TIE
COIL SENSOR − Clip coil temperature sensor from the defrost board on the return bend shown on models as follows:
Model −024 & −036: 12 tubes up from bottom (11−1/2"); Model −048 & −060 (before April 2006): 16 tubes up from bottom (15−1/2") Model −048 & −060 (after April 2006): 24 tubes up from bottom (23−1/2")
Models −024 & −036
Models −048 & −060
16 tubes
up (before
April 2006)
12 tubes up
Ambient SensorThe ambient sensor (shown in detail A, figure 17) considers outdoor temperatures below −35°F (−37°C) or above 120°F (48°C) as a problem. If the ambient sensor is detected as being open, shorted or out of the tem­perature range of the sensor, the board will not perform de­mand defrost operation. The board will revert to time/tem­perature defrost operation and will display the appropriate fault code. Heating and cooling operation will be allowed in this fault condition.
Coil SensorThe coil temperature sensor (shown in de­tail B, figure 17) considers outdoor temperatures below
−35°F (−37°C) or above 120°F (48°C) as a problem. If the coil temperature sensor is detected as being open, shorted or out of the temperature range of the sensor, the board will not perform demand or time/temperature defrost operation and will display the appropriate fault code. Heating and cooling operation will be allowed in this fault condition.
Discharge Line SensorIf the discharge line tempera­ture (shown in figure 17) exceeds a temperature of 285°F (140°C) during compressor operation, the board will de−en­ergize the compressor contactor output (and the defrost output, if active). The compressor will remain off until the discharge temperature has dropped below 225°F (107°C) and the 5-minute anti−short cycle delay has been satisfied. This sensor has two fault and lockout codes:
3−. If the board recognizes five high discharge line temper-
ature faults during a single (Y1) compressor demand, it reverts to a lockout mode and displays the appropri­ate code. This code detects shorted sensor or high dis­charge temperatures. (Code on board is Discharge Line Temperature Fault and Lockout").
Page 15
4−. If the board recognizes five temperature sensor range
faults during a single (Y1) compressor demand, it re­verts to a lockout mode and displays the appropriate code. The board detects open sensor or out-of-tem­perature sensor range. This fault is detected by allow­ing the unit to run for 90 seconds before checking sen­sor resistance. If the sensor resistance is not within range after 90 seconds, the board will count one fault. After 5 faults, the board will lockout. (Code on board is
Discharge Sensor Fault and Lockout"). The discharge line sensor, which covers a range of 150°F (65°C) to 350°F (176°C), is designed to mount on a ½" re­frigerant discharge line.
NOTE − Within a single room thermostat demand, if 5−strikes occur, the board will lockout the unit. Defrost board 24 volt power R" must be cycled OFF" or the TEST" pins on board must be shorted between 1 to 2 sec­onds to reset the board.
Second−Stage OperationIf the board receives a call for second−stage compressor operation Y2" in heating or cooling mode and the first-stage compressor output is ac­tive, the second-stage compressor solenoid output will be energized by the LSOM.
NOTE − The LSOM has a 5 second delay between Y2 being powered and the solenoid energizing.
If first-stage compressor output is active in heating mode and the outdoor ambient temperature is below the selected compressor lock−in temperature, the second-stage com­pressor solenoid output will be energized without the Y2" room thermostat input. If the jumper is not connected to one of the temperature selection pins on P3 (40, 45, 50, 55°F), the default lock−in temperature of 40°F (4.5°C) will be used.
The board de−energizes the second-stage compressor so­lenoid output immediately when the Y2" signal is removed or the outdoor ambient temperature is 5°F above the se­lected compressor lock−in temperature, or the first-stage compressor output is de−energized for any reason.
Defrost Temperature Termination Shunt (Jumper) PinsThe defrost board selections are: 50, 70, 90, and
100°F (10, 21, 32 and 38°C). The shunt termination pin is factory set at 50°F (10°C). If the temperature shunt is not installed, the default termination temperature is 90°F (32°C).
Delay Mode
The defrost board has a field−selectable function to reduce occasional sounds that may occur while the unit is cycling in and out of the defrost mode. When a jumper is installed on the DELAY pins, the compressor will be cycled off for 30 seconds going in and out of the defrost mode. Units are shipped with jumper installed on DELAY pins.
NOTE − The 30 second off cycle is NOT functional when jumpering the TEST pins.
Operational Description
The defrost control board has three basic operational modes: normal, calibration, and defrost.
Normal ModeThe demand defrost board monitors the O line, to determine the system operating mode (heat/cool), outdoor ambient temperature, coil temperature (outdoor coil) and compressor run time to determine when a defrost cycle is required.
Calibration ModeThe board is considered uncalibrated when power is applied to the board, after cool mode opera­tion, or if the coil temperature exceeds the termination tem­perature when it is in heat mode.
Calibration of the board occurs after a defrost cycle to en­sure that there is no ice on the coil. During calibration, the temperature of both the coil and the ambient sensor are measured to establish the temperature differential which is required to allow a defrost cycle. See figure 19 for calibra­tion mode sequence.
Defrost ModeThe following paragraphs provide a de­tailed description of the defrost system operation.
Detailed Defrost System Operation
Defrost CyclesThe demand defrost control board initi-
ates a defrost cycle based on either frost detection or time. Frost DetectionIf the compressor runs longer than 34
minutes and the actual difference between the clear coil and frosted coil temperatures exceeds the maxi­mum difference allowed by the control, a defrost cycle will be initiated.
TimeIf 6 hours of heating mode compressor run time has
elapsed since the last defrost cycle while the coil tem­perature remains below 35°F (2°C), the demand de­frost control will initiate a defrost cycle.
Page 16
ActuationWhen the reversing valve is de−energized, the Y1 circuit is energized, and the coil temperature is below 35°F (2°C), the board logs the compressor run time. If the board is not calibrated, a defrost cycle will be initiated after 34 minutes of heating mode compressor run time. The con­trol will attempt to self−calibrate after this (and all other) de­frost cycle(s).
Calibration success depends on stable system tempera­tures during the 20−minute calibration period. If the board fails to calibrate, another defrost cycle will be initiated after 45 minutes (90 minutes for −1 to −4 boards) of heating mode compressor run time. Once the defrost board is calibrated, it initiates a demand defrost cycle when the difference be­tween the clear coil and frosted coil temperatures exceeds the maximum difference allowed by the control OR after 6 hours of heating mode compressor run time has been logged since the last defrost cycle.
NOTE − If ambient or coil fault is detected, the board will not execute the TEST" mode.
TerminationThe defrost cycle ends when the coil tem­perature exceeds the termination temperature or after 14 minutes of defrost operation. If the defrost is terminated by the 14−minute timer, another defrost cycle will be initiated after 34 minutes of run time.
Test ModeWhen Y1 is energized and 24V power is be­ing applied to the board, a test cycle can be initiated by placing the termination temperature jumper across the Test" pins for 2 to 5 seconds. If the jumper remains across the Test" pins longer than 5 seconds, the control will ignore the test pins and revert to normal operation. The jumper will initiate one cycle per test.
Enter the TEST" mode by placing a shunt (jumper) across the TEST" pins on the board after power−up. (The TEST" pins are ignored and the test function is locked out if the shunt is applied on the TEST" pins before power−up). Board timings are reduced, the low−pressure switch and loss of charge detection fault is ignored and the board will clear any active lockout condition.
Each test pin shorting will result in one test event. For each TEST" the shunt (jumper) must be removed for at least 1 second and reapplied. Refer to flow chart (figure 18) for TEST" operation.
Note: The Y1 input must be active (ON) and the O" room thermostat terminal into board must be inactive.
Defrost Board Diagnostics
See table 6 to determine defrost board operational condi­tions and to diagnose cause and solution to problems.
If in COOLING Mode If in HEATING Mode If in DEFROST Mode
Short test pins for longer
than 1 second but less than
2.0 seconds
Short test pins for more than 2.0 seconds
Y1 Active (0" line inactive)
FIGURE 18
Test Mode
Test pin short REMAINS in place for more than 5 seconds Test pins short REMOVED before a
maximum of 5 seconds
Clear any short cycle lockout
and 5 strike fault lockout
function, if applicable. No
other functions will be executed and unit will
continue in the mode it was
operating.
No further test mode
operation will be
executed until the test
short is removed and
reapplied.
The controller will check for
ambient and coil faults (open or
shorted). If a fault exists, the
unit will remain in Heat Mode
and no further test mode
operation will be executed until
the test short is removed and re
applied. If no fault exists, the
unit will go into Defrost mode.
The unit will terminate
defrost and enter Heat
Mode uncalibrated with
defrost timer set for 34 minute test. No further
test mode operation will
be executed until the test
short is removed and
reapplied.
Clear any short cycle lockout and 5 strike
fault lockout function, if applicable.
The unit will return to Heat mode uncalibrated with defrost
timer set for 34 minutes. No further test mode operation will
be executed until the test short is removed and re applied.
The unit will remain in Defrost mode
until termination on time or temperature
Page 17
Calibration Mode Sequence
Occurs after power up, after cooling operation, or if the coil temperature exceeds the termination
temperature while in Heat Mode.
DCB defaults to 34 minutes Time/Temperature Mode Reset Compressor Runtime / Reset Three / Five Strike Counter
DEMAND MODE
Accumulate compressor run­time while coil temperature is below 35° F (2°C). When the accumulated compres­sor time exceeds 6 hours or if the coil sensor indicates frost is present on coil, go to Defrost.
34 MIN. TIME/TEMP. MODE
Accumulate compressor run­time while coil temperature is below 35° F (2°C). When the accumulated compressor time exceeds 34 minutes go to Defrost.
45 MIN. TIME/TEMP. MODE (90 min for −1 to −4 boards)
Accumulate compressor run­time while coil temperature is below 35° F (2°C). When the accumulated compressor time exceeds 90 minutes go to Defrost.
DEFROST
OUTDOOR FAN Off
Reversing Valve ON
W1 line ON
Monitor coil temperature
and time in defrost mode.
HOW DID DEFROST TERMINATE?
Coil temperature was above 35°F (2°C) for 4 min. of the 14 min. de-
frost OR reached defrost
termination temp.
DCB’s 60L3901 and 46M8201
LO−PS Termination Option
selected. Defrost terminated by
pressure.
Defrosted for 14 min. with-
out the coil temp. going
above 35°F (2°C) for 4
min and coil did not reach
termination temp.
At termination of defrost the compressor
runtime counter is reset/Turn on Outdoor
FAN /Rev Valve & W1 turn off.
At Termination of Defrost
the compressor runtime
counter is reset/Turn on
Outdoor FAN/Rev valve &
W turn OFF
Attempt to Calibration−Temperature measurements are not taken
for the first few minutes of each heat demand. This is to allow coil
temperatures to stabilize. DCB has a maximum of 20 minutes of accumulated compressor runtime in heat mode to calibrate DCB
This may involve more than one heating demand.
YES, calibration occurred
Was stable coil temp. attained
within 20 minutes?
NO, DCB reverts to 45 min. (90
min. for −1 to −4 boards) time/temp.
FIGURE 19
Page 18
TABLE 6
Defrost Control Board Diagnostic LEDs
DS2 Green
DS1 Red
Condition/Code Possible Cause(s) Solution
OFF OFF Power problem No power (24V) to board termi-
nals R & C or board failure.
1
Check control transformer power (24V).
2
If power is available to board and LED(s) do not light, replace board.
Simultaneous SLOW Flash
Normal operation Unit operating normally or in
standby mode.
None required.
Alternating SLOW Flash
5−minute anti−short cycle delay
Initial power up, safety trip, end of room thermostat demand.
None required (Jumper TEST pins to override)
Simultaneous FAST Flash
Ambient Sensor Problem Sensor being detected open or shorted or out of temperature range. Board will re-
vert to time/temperature defrost operation. (System will still heat or cool).
Alternating FAST Flash
Coil Sensor Problem Sensor being detected open or shorted or out of temperature range. Board will not
perform demand or time/temperature defrost operation. (System will still heat or cool).
ON ON Circuit Board Failure Indicates that board has internal component failure. Cycle 24 volt power to board. If
code does not clear, replace board.
FAULT & LOCKOUT CODES (Each fault adds 1 strike to that code’s counter; 5 strikes per code = LOCKOUT)
OFF SLOW
Flash
Low Pressure Fault
1
Restricted air flow over indoor or outdoor coil.
2
Improper refrigerant charge in
1
Remove any blockages or restrictions from coils and/or fans. Check indoor and outdoor fan motor for proper current draws.
OFF ON Low Pressure LOCKOUT
pp g g
system.
3
Improper metering device
pp
2
Check system charge using approach & sub­cooling temperatures.
SLOW Flash
OFF High Pressure Fault
installed
or incorrect operation
of metering device.
4
Incorrect or improper sensor location or connection to sys-
3
Check
system operating pressures an
d
compare to unit charging charts.
4
Make sure all pressure switches and sensors have secure connections to system to prevent
ON OFF High Pressure LOCKOUT
location or connection to sys
tem.
have secure connections to system to prevent
refrigerant leaks or errors in pressure and temperature measurements.
SLOW Flash
ON Discharge Line Tempera-
ture Fault
This code detects shorted sensor or high discharge temperatures. If the discharge line temperature exceeds a temperature of 285ºF (140ºC) during compressor op-
-
FAST Flash
ON Discharge Line Tempera-
ture LOCKOUT
eration, the board w
ill d
e−energize the compressor contactor output (and the de­frost output if active). The compressor will remain off until the discharge tempera­ture has dropped below 225ºF (107ºC).
OFF Fast
Flash
Discharge Sensor Fault The board detects open sensor or out of temperature sensor range. This fault is
detected by allowing the unit to run for 90 seconds before checking sensor resist-
Fast Flash
OFF Discharge Sensor
LOCKOUT
ance. If the sensor resistance is not within range after 90 seconds, the board will count one fault. After 5 faults, the board will lockout.
Page 19
K−Crankcase Heater (HR1)
Compressors in all units are equipped with a 70 watt belly­band type crankcase heater. HR1 prevents liquid from ac­cumulating in the compressor. HR1 is controlled by the crankcaseheater thermostat.
L− Crankcase heater Thermostat (S40)
Thermostat S40 controls the crankcase heater in all units. S40 is located on the liquid line. When liquid line tempera­ture drops below 50° F the thermostat S40 closes energizing HR1. The thermostat will open, de−energizing HR1 once liq­uid line temperature reaches 70° F .
III−REFRIGERANT SYSTEM
IMPORTANT
The Clean Air Act of 1990 bans the intentional vent­ing of (CFC’s and HFC’s) as of July 1, 1992. Approved methods of recovery, recycling or reclaiming must be followed. Fines and/or incarceration my be levied for noncompliance.
Field refrigerant piping consists of liquid and vapor lines from the outdoor unit (sweat connections). Use Lennox L15 series line sets as shown in table 7. Separate liquid and suction service ports are provided at the service valves for connection of gauge manifold during charging procedure. Figure 20 shows XP19 refrigerant flow and gauge manifold connections.
TABLE 7
Valve Field Size
Connections
Recommended Line Set
Model
Liquid
Line
Vapor
Line
Liquid
Line
Vapor
Line
L15
Line Sets
−024,− 036
3/8 in.
10 mm
7/8 in.
22 mm
3/8 in.
10 mm
7/8 in.
19 mm
L15−65
15 ft. − 50 ft.
4.6 m − 15 m
−048
3/8 in.
10 mm
1−1/8 in.
29 mm
3/8 in.
10 mm
7/8 in.
22 mm
L15−65
15 ft. − 50 ft.
4.6 m − 15 m
−060
3/8 in.
10 mm
1−1/8 in.
29 mm
3/8 in.
10 mm
1−1/8 in.
29 mm
Field
Fabricated
XP19 COOLING CYCLE
(Showing Gauge Manifold Connections)
NOTE−Use gauge ports on vapor line valve and liquid valve for evacuating refrigerant lines and indoor coil. Use suction gauge port to measure suction pressure during charging.
OUTDOOR
COIL
EXPANSION/
CHECK VALVE
BIFLOW
FILTER / DRIER
TO
R410A
DRUM
LOW
PRESSURE
HIGH
PRESSURE
COMPRESSOR
REVERSING VALVE
VAPOR
LINE
VALV E
MUFFLER
NOTE − ARROWS INDICATE
DIRECTION OF REFRIGERANT FLOW.
REFRIGERANT WILL FLOW IN OPPOSITE
DIRECTION IN HEATING CYCLE.
SERVICE
PORT
SUCTION
EXPANSION/CHECK
VALV E
INDOOR UNIT
OUTDOOR UNIT
LIQUID
LINE
SERVICE
PORT
GAUGE MANIFOLD
DISTRIBUTOR
INDOOR
COIL
FIGURE 20
Page 20
A−Service Valves
Access the liquid line and vapor line service valves (figures 21 and 22) and gauge ports are used for leak testing, eva­cuating, charging and checking charge. See table 8 for torque requirements.
Each valve is equipped with a service port which has a fac­tory−installed Schrader valve. A service port cap protects the Schrader valve from contamination and serves as the primary leak seal.
TABLE 8
Part 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
IMPORTANT
Service valves are closed to the outdoor unit and open to line set connections. Do not open the valves until refrigerant lines have been leak tested and evacuated. All precautions should be exercised to keep the system free from dirt, moisture and air.
To Access Schrader Port:
1 − Remove service port cap with an adjustable wrench. 2 − Connect gauge to the service port. 3 − When testing is complete, replace service port cap.
Tighten finger tight, then an additional 1/6 turn.
To Open Service Valve:
1 − Remove stem cap with an adjustable wrench. 2 − Using service wrench and hex head extension, back
the stem out counterclockwise as far as it will go.
NOTE − Use a 3/16" hex head extension for liquid line size.
3 − Replace stem cap and tighten it firmly. Tighten finger
tight, then tighten an additional 1/6 turn.
To Close Service Valve:
1 − Remove stem cap with an adjustable wrench. 2 − Using service wrench and hex head extension, turn
stem clockwise to seat valve. Tighten it firmly.
NOTE − Use a 3/16" hex head extension for liquid line size.
3 − Replace stem cap. Tighten finger tight, then tighten an
additional 1/6 turn.
Vapor Line (Ball Type) Valve
Vapor line service valves function the same way as the oth­er valves, the difference is in the construction. These valves are not rebuildable. If a valve has failed, you must replace it. A ball valve valve is illustrated in figure 22.
The ball valve is equipped with a service port with a factory− installed Schrader valve. A service port cap protects the Schrader valve from contamination and assures a leak− free seal.
Front-Seated Liquid Line Service Valve
(Valve Shown Closed)
Insert hex wrench here
SCHRADER VALV E
SERVICE
PORT
To outdoor coil
STEM CAP
STEM CAP
(VALVE front-
seated)
To outdoor coil
SCHRADER
VALV E
[open to line set
when valve is
closed (front
seated)]
(Valve Shown Open)
insert hex wrench here
To
indoor coil
SERVICE PORT CAP
SERVICE PORT
SERVICE PORT CAP
To
indoor coil
FIGURE 21
Vapor Line (Ball Type) Service Valve
(Valve Open)
FIGURE 22
BALL (Shown closed)
STEM
STEM CAP
SERVICE
PORT
SCHRADER
VALV E
SERVICE
PORT CAP
To indoor coil
To outdoor coil
Use Adjustable Wrench To close: rotate Stem Counter-clockwise 90°. To open: rotate Stem Clockwise 90°.
Page 21
IV−CHARGING
Units are factory charged with the amount of R410A refrig­erant indicated on the unit rating plate. This charge is based on a matching indoor coil and outdoor coil with 15 ft. (4.6m) line set. For varying lengths of line set, refer to table 9 for refrigerant charge adjustment.
TABLE 9
Liquid Line Set
Diameter
Ozs. per 5 ft. (grams per 1.5m) adjust
from 15 ft. (4.6m) line set*
3/8 in.
(9.5mm)
3 ounces per 5 feet
(85g per 1.5m)
*If line length is greater than 15 ft. (4.6m), add this amount. If line length is less than 15 ft. (4.6), subtract this amount.
A−Leak Testing
After the line set has been connected to the indoor and out­door units, the line set connections and indoor unit must be checked for leaks.
WARNING
Refrigerant can be harmful if inhaled. Refrigerant must be used and recovered responsibly. Failure to follow this warning can lead to injury or death.
WARNING
Fire, Explosion and Personal Safety Hazard. Failure to follow this warning could result 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 damage by fire and or an explosion, that could result in personal injury or death.
WARNING
Danger of explosion: Can cause equipment damage, injury or death. When using a high pressure gas such as dry 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).
Using an Electronic Leak Detector
1 − Connect a cylinder of R410A to the center port of the
manifold gauge set.
2 − With both manifold valves closed, open the valve on
the R410A cylinder (vapor only).
3 − Open the high pressure side of the manifold to allow
the R410A into the line set and indoor unit. Weigh in a trace amount of R410A . [A trace amount is a maximum of 2 ounces (57 g) or 3 pounds (31 kPa) pressure.] Close the valve on the R410A cylinder and the valve on the high pressure side of the manifold gauge set. Disconnect the R410A cylinder.
4 − Connect a cylinder of nitrogen with a pressure regulat-
ing valve to the center port of the manifold gauge set.
5 − Connect the manifold gauge set high pressure hose to
the vapor valve service port. (Normally, the high pres-
sure 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.)
6 − Adjust the nitrogen pressure to 150 psig (1034 kPa).
Open the valve on the high side of the manifold gauge set which will pressurize line set and indoor unit.
7 − After a few minutes, open a refrigerant port to ensure
the refrigerant you added is adequate to be detected. (Amounts of refrigerant will vary with line lengths.) Check all joints for leaks. Purge nitrogen and R410A mixture. Correct any leaks and recheck.
IMPORTANT
Leak detector must be capable of sensing HFC re­frigerant.
B−Evacuating
Evacuating the system of noncondensables is critical for proper operation of the unit. Noncondensables are defined as any gas that will not condense under temperatures and pressures present during operation of an air conditioning system. Noncondensables and water vapor combine with refrigerant to produce substances that corrode copper pip­ing and compressor parts.
IMPORTANT
Use a thermocouple or thermistor electronic vacuum gauge that is calibrated in microns. Use an instrument that reads from 50 microns to at least 23,000 microns.
1 − Connect the manifold gauge set to the service valve
ports as follows:
low pressure gauge to vapor line service valvehigh pressure gauge to liquid line service valve
2 − Connect micron gauge.
3 − Connect the vacuum pump (with vacuum gauge) to the
center port of the manifold gauge set.
4 − Open both manifold valves and start vacuum pump.
5 − Evacuate the line set and indoor unit to an absolute
pressure of 23,000 microns (29.01 inches of mercu­ry). During the early stages of evacuation, it is desir­able to close the manifold gauge valve at least once to determine if there is a rapid rise in absolute pressure. A rapid rise in pressure indicates a relatively large leak. If this occurs, repeat the leak testing procedure.
NOTE − The term absolute pressure means the total actual pressure within a given volume or system, above the absolute zero of pressure. Absolute pres­sure in a vacuum is equal to atmospheric pressure mi­nus vacuum pressure.
6 − 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.
Page 22
Attach the manifold center port hose to a 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.
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.
7 − Shut off the nitrogen cylinder and remove the manifold
gauge hose from the cylinder. Open the manifold gauge valves to release the nitrogen from the line set and indoor unit.
8 − Reconnect the manifold gauge to the vacuum pump,
turn the pump on, and continue to evacuate the line set and indoor 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.
9 − 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 R410A refrigerant. Open the manifold gauge valves to break the vacuum from 1 to 2 psig positive pressure in the line set and indoor unit. Close manifold gauge valves and shut off the R410A cylinder and remove the manifold gauge set.
C−Charging
This system is charged with R410A refrigerant which oper­ates at much higher pressures than R22. The check/ex­pansion valve provided with the unit is approved for use with R410A. Do not replace it with a valve designed for use with R22. This unit is NOT approved for use with coils which include metering orifices or capillary tubes.
Processing Procedure
The unit is factory−charged with the amount of R410A re­frigerant indicated on the unit rating plate. This charge is based on a matching indoor coil and outdoor coil with a 15 foot (4.6m) line set. For varying lengths of line set, refer to table 9 for refrigerant charge adjustment. .
IMPORTANT
Mineral oils are not compatible with R410A. If oil must be added, it must be a polyol ester oil.
It is desirable to charge the system in the cooling cycle if weather conditions permit. However, if the unit must be charged in the heating season, one of the following proce­dures must be followed to ensure proper system charge.
Weighing in the Charge TXV Systems –
Outdoor Temp. < 65F (18C)
If the system is void of refrigerant, or if the outdoor ambient temperature is cool, the refrigerant charge should be weighed into the unit. Do this after any leaks have been re­paired.
1 − Recover the refrigerant from the unit. 2 − Conduct a leak check, then evacuate as previously
outlined. 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.
Subcooling Method
Outdoor Temp. < 65°F (18°C)
When the outdoor ambient temperature is below 65°F (18°C), 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 (2240−2585 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 (2240−2585 kPa) range. Figure 23 shows a four sided unit for example..
Blocking Outdoor Coil
cardboard or
plastic sheet
Outdoor coil should be
blocked one side
at a time with cardboard
or plastic sheet until proper
testing pressures
are reached.
FIGURE 23
1 − With the manifold gauge hose still on the liquid service
port and the unit operating stably, use a digital ther-
mometer to record the liquid line temperature. 2 − At the same time, record the liquid line pressure reading. 3 − Use a temperature/pressure chart for R410A to deter-
mine the saturation temperature for the liquid line pres-
sure reading. See table 14. 4 − Subtract the liquid line temperature from the saturation
temperature (according to the chart) to determine sub-
cooling. (Saturation temperature − Liquid line tem-
perature = Subcooling)
5 − Compare the subcooling value with those in table 10. If
subcooling is greater than shown, recover some refrig-
erant. If subcooling is less than shown, add some re-
frigerant. Be aware of the R410A refrigerant cylinder. It
will be light maroon−colored. Refrigerant should be
added through the vapor line valve in the liquid state.
Some R410A cylinders are equipped with a dip
tube that allows you to draw liquid refrigerant from
the bottom of the cylinder without turning the cyl-
inder upside−down. The cylinder will be marked if it
is equipped with a dip tube.
Page 23
TABLE 10
2nd stage High Capacity
Subcooling Values for Charging
Model
Second-Stage (High Capacity) Subcooling Values
− Conversion Temp. − Liquid Line Temp. °F (°C)
XP19−024 8.0 + 1 (4.4 + .5)
XP19−036 6.0 + 1 (3.3 + .5)
XP19−048 6.0 + 1 (3.3 + .5)
XP19−060 6.0 + 1 (3.3 + .5)
Charging Using Normal Operating Pressures
and the Approach Method
Outdoor Temp. >
65F (18C)
The following procedure is intended as a general guide and is for use on expansion valve systems only. 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
tables 12 and 13, Normal Operating Pressures." Mi­nor variations in these pressures may be expected due to differences in installations. 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.
Approach Method
4 − Use the same digital thermometer used to check out-
door ambient temperature to check liquid line tempera­ture. Verify the unit charge using the approach method.
5 − The difference between the ambient and liquid temper-
atures should match values given in table 11. If the val­ues don’t agree with the those in table 11, add refriger­ant to lower the approach temperature or recover re­frigerant from the system to increase the approach temperature.
TABLE 11
2nd Stage High Capacity
Approach Values for Charging
Model
Second-Stage (High Capacity) Approach Temp. − Liquid Line Temp. − Outdoor Ambient °F (°C)
XP19−024 7.0 + 1 (3.9 + .5)
XP19−036 9.0 + 1 (5.0 + .5)
XP19−048 7.0 + 1 (3.9 + .5)
XP19−060 9.0 + 1 (5.0 + .5)
IMPORTANT
Use table 12 and table 13 as a general guide when performing maintenance checks. This is not a proce­dure for charging the unit (Refer to Charging/Check­ing Charge section). Minor variations in these pres­sures may be expected due to differences in installa­tions. Significant differences could mean that the system is not properly charged or that a problem ex­ists with some component in the system.
TABLE 12
Normal Operating Pressure (Heating
Operation) − Liquid +
10 & Vapor +5 PSIG*
XP19−024 XP19−036 XP19−048 XP19−060
Outd
oor Co
il
Entering Air Temperature 5F (5C)
LIQ ­UID
VA-
PO
R
LIQ ­UID
VA-
PO
R
LIQ ­UID
VA-
PO
R
LIQ ­UID
VA-
PO
R
First Stage (Low Capacity)
40 (4.4) 302 99 301 95 324 93 342 90
50 (10) 318 121 317 11 4 351 117 388 112
Second Stage (High Capacity)
20 (−7.0) 280 67 280 57 337 74 346 60
30 (−1.0) 297 82 298 75 342 76 365 71
40 (4.4) 317 99 313 89 352 89 390 84
50 (10) 330 118 328 87 379 107 402 104
*These are typical pressures only. Indoor match up, indoor air quality, and indoor load will cause the pressures to vary.
TABLE 13
Normal Operating Pressure (Cooling
Operation) − Liquid +
10 & Vapor +5 PSIG*
XP19−024 XP19−036 XP19−048 XP19−060
Outd
oor Co
il
Entering Air Temperature 5F (5C)
LIQ ­UID
VA-
PO
R
LIQ ­UID
VA-
PO
R
LIQ ­UID
VA-
PO
R
LIQ ­UID
VA-
PO
R
First Stage (Low Capacity)
65 (18.3) 226 152 230 148 210 136 234 135
75 (23.9) 262 151 267 150 242 138 274 137
85 (29.4) 304 152 309 153 286 140 314 142
95 (35.0) 351 155 355 155 328 142 361 147
105 (40.6) 400 158 404 157 374 144 413 147
115 (49.0) 454 161 460 159 426 146 470 149
Second Stage (High Capacity)
65 (18.3) 228 146 236 144 227 114 237 131
75 (23.9) 267 148 275 145 265 123 276 133
85 (29.4) 309 149 318 148 306 132 320 135
95 (35.0) 358 151 365 150 348 138 369 138
105 (40.6) 410 152 416 153 397 141 423 140
115 (49.0) 465 154 473 155 453 143 482 144
*These are typical pressures only. Indoor match up, indoor air quality, and indoor load will cause the pressures to vary.
Page 24
Table 14
R410A Temperature/Pressure Chart
Temperature°FPressure
Psig
Temperature°FPressure
Psig
Temperature°FPressure
Psig
Temperature°FPressure
Psig
32 100.8 63 178.5 94 290.8 125 445.9 33 102.9 64 181.6 95 295.1 126 451.8
34 105.0 65 184.3 96 299.4 127 457.6 35 107.1 66 187.7 97 303.8 128 463.5 36 109.2 67 190.9 98 308.2 129 469.5 37 111.4 68 194.1 99 312.7 130 475.6 38 113.6 69 197.3 100 317.2 131 481.6 39 115.8 70 200.6 101 321.8 132 487.8 40 118.0 71 203.9 102 326.4 133 494.0 41 120.3 72 207.2 103 331.0 134 500.2 42 122.6 73 210.6 104 335.7 135 506.5 43 125.0 74 214.0 105 340.5 136 512.9 44 127.3 75 217.4 106 345.3 137 519.3 45 129.7 76 220.9 107 350.1 138 525.8 46 132.2 77 224.4 108 355.0 139 532.4 47 134.6 78 228.0 109 360.0 140 539.0 48 137.1 79 231.6 11 0 365.0 141 545.6 49 139.6 80 235.3 111 370.0 142 552.3 50 142.2 81 239.0 11 2 375.1 143 559.1 51 144.8 82 242.7 11 3 380.2 144 565.9 52 147.4 83 246.5 11 4 385.4 145 572.8 53 150.1 84 250.3 11 5 390.7 146 579.8 54 152.8 85 254.1 11 6 396.0 147 586.8 55 155.5 86 258.0 11 7 401.3 148 593.8 56 158.2 87 262.0 11 8 406.7 149 601.0 57 161.0 88 266.0 11 9 412.2 150 608.1 58 163.9 89 270.0 120 417.7 151 615.4 59 166.7 90 274.1 121 423.2 152 622.7 60 169.6 91 278.2 122 428.8 153 630.1 61 172.6 92 282.3 123 434.5 154 637.5 62 195.5 93 286.5 124 440.2 155 645.0
Page 25
V−SERVICE AND RECOVERY
WARNING
Polyol ester (POE) oils used with R410A 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.
IMPORTANT − Use recovery machine rated for R410 refrigerant.
If the XP19 system must be opened for any kind of service, such as compressor or filter drier replacement, you must take extra precautions to prevent moisture from entering the system. The following steps will help to minimize the amount of moisture that enters the system during recovery of R410A.
1 − Use a regulator−equipped nitrogen cylinder to break
the system vacuum. Do not exceed 5 psi. The dry ni­trogen will fill the system, and will help purge any mois­ture.
2 − Remove the faulty component and quickly seal the
system (using tape or some other means) to prevent additional moisture from entering the system.
3 − Do not remove the tape until you are ready to install
new component. Quickly install the replacement com­ponent.
4 − Evacuate the system to remove any moisture and oth-
er non−condensables.
The XP19 system MUST be checked for moisture any time the sealed system is opened.
Any moisture not absorbed by the polyol ester oil can be re­moved by triple evacuation. Moisture that has been ab­sorbed by the compressor oil can be removed by replacing the filter drier.
IMPORTANT
Evacuation of system only will not remove mois­ture from oil. Filter drier must be replaced to elimi­nate moisture from POE oil.
VI−MAINTENANCE
WARNING
Electric shock hazard. Can cause inju­ry or death. Before attempting to per­form any service or maintenance, turn the electrical power to unit OFF at dis­connect switch(es). Unit may have multiple power supplies.
Maintenance and service must be performed by a quali­fied installer or service agency. At the beginning of each cooling or heating season, the system should be checked as follows:
Outdoor Unit
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 prelubricated 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 and compres-
sor (high and low capacity).
7 − Inspect drain holes in coil compartment base and
clean if necessary.
NOTE − If owner complains of insufficient cooling, the unit should be gauged and refrigerant charge checked. Refer to
section on refrigerant charging in this instruction.
VII−BRAZING
Before brazing remove access panels and any piping pan­els to avoid burning off paint. Be aware of any components ie, service valves, reversing valve, pressure switches that may be damaged due to brazing heat.
When making line set connections, use 1 to 2 psig dry nitro­gen to purge the refrigerant piping. This will help to prevent oxidation into the system.
WARNING
Danger of explosion: Can cause equipment damage, injury or death. When using a high pressure gas such as dry 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).
1 − .Cut ends of copper square (free from nicks or dents).
Debur the ends. The pipe must remain round, do not
pinch end of line.
2 − Wrap wet rag around any components that may be da-
maged.
3 − Use silver alloy brazing rods (5 or 6 percent minimum
silver alloy for copper to copper brazing or 45 percent silver alloy for copper to brass or copper to steel braz­ing) which are rated for use with R−22 and R−410A re­frigerant.
4 − After brazing quench the joints with a wet rag to prevent
possible heat damage to any components.
Page 26
VIII−DIAGRAM / OPERATING SEQUENCE
Page 27
Sequence of Operation XP19−024/060
First Stage Cool (low capacity)
Transformer from indoor unit supplies 24VAC power to the thermostat and outdoor unit controls.
1− Internal wiring energizes terminal O by cooling mode
selection, energizing the reversing valve. Cooling de­mand initiates at Y1 in the thermostat.
2− 24VAC passes through high pressure switch S4 and
discharge thermostat switch S5 energizing compres­sor contactor K1.
3− K1−1 N.O. closes energizing compressor B1 and out-
door fan motor B4.
4− Solenoid L34 is NOT energized. The slider ring re-
mains open limiting compressor to low capacity.
Second Stage Cool (high capacity)
5− Second stage thermostat demand sends voltage to the
LSOM. After a 5 second delay the LSOM converts the AC voltage to DC voltage and energizes solenoid L34. L34 then closes the slider ring, allowing the compres­sor to operate at high capacity. Variable speed outdoor fan operates on high speed (blue tap).
Heating
A – Low Capacity
1 − Room thermostat in heating mode. Room thermostat
outputs Y1 signal to the defrost board in the heat pump and to the indoor air handler.
2 − The defrost board checks for open low or high−pres-
sure switches and proper coil, ambient and discharge sensor readings. If checks show no issues, the defrost board sends 24 volts through Y1 OUT signal to the K1 compressor contactor coil, the Y1 terminal on the diag­nostic module (A132) and the yellow wire to the out­door fan motor.
3 − K1−1 closes, energizing the compressor and puts 240
volts into the outdoor fan motor through the normally closed fan relay contacts on the defrost board.
4 − The compressor will run on low capacity and the 24volt
input on the yellow wire to the outdoor fan motor will al­low it to run on low speed.
B – High Capacity (Ambient temperature above
de-
frost board Y2 lock−in temperature)
1 − Room thermostat in heating mode. Room thermostat
outputs Y1 and Y2 (if applicable to that room thermo­stat) signal to the defrost board in the heat pump and to the indoor unit.
2 − The defrost board checks for open low or high−pres-
sure switches and proper coil, ambient and discharge sensor readings. If checks show no issues, the defrost board sends 24 volts through Y1 OUT signal to the K1 compressor contactor coil, the Y1 terminal on the diag­nostic module (A132) and the yellow wire to the out­door fan motor.
3 − The defrost board sends 24 volts through Y2 OUT sig-
nal to the Y2 terminal on the diagnostic module (A132) and the blue wire to the outdoor fan motor.
4 − K1−1 closes, energizing the compressor and puts 240
volts into the outdoor fan motor through the normally closed fan relay contacts on the defrost board.
5 − The compressor will run on low capacity for 5 seconds.
The diagnostic module (LSOM) will confirm low stage operation and then output a 24volt DC signal to the L34 internal high capacity solenoid valve in the compres­sor. Once the solenoid is energized, the diagnostic module will continue pulsing 6 to 18 volt DC signal to the solenoid to keep it energized during the Y2 room thermostat demand.
6 − The 24volt inputs to the yellow and blue wires of the
outdoor fan motor will provide high−speed operation.
B – High Capacity (Ambient temperature below
de-
frost board Y2 lock−in temperature)
1 − Room thermostat in heating mode. Room thermostat
outputs Y1 signal to the defrost board in the heat pump and to the indoor unit.
2 − The defrost board checks for open low or high−pres-
sure switches and proper coil, ambient and discharge sensor readings. If checks show no issues, the defrost board sends 24 volts through Y1 OUT signal to the K1 compressor contactor coil, the Y1 terminal on the diag­nostic module (A132) and the yellow wire to the out­door fan motor.
3 − The defrost board Y2 locks in
sends 24 volts through Y2 OUT signal to the Y2 terminal on the diagnostic module (A132) and the blue wire to the outdoor fan mo­tor.
4 − K1−1 closes, energizing the compressor and puts 240
volts into the outdoor fan motor through the normally closed fan relay contacts on the defrost board.
5 − The compressor will run on low capacity for 5 seconds.
The diagnostic module (LSOM) will confirm low stage operation and then output a 24volt DC signal to the L34 internal high capacity solenoid valve in the compres­sor. Once the solenoid is energized, the diagnostic module will continue pulsing 6 to 18 volt DC signal to the solenoid to keep it energized during the Y2 opera­tion.
6 − The 24volt inputs to the yellow and blue wires of the
outdoor fan motor will provide high−speed operation.
Defrost Mode
When a defrost cycle is initiated, the control ener­gizes the reversing valve solenoid and turns off the condenser fan. The control will also put 24VAC on the W1" (auxiliary heat) line. The unit will stay in this mode until either the coil sensor temperature is above the selected termination temperature, the de­frost time of 14 minutes has been completed, or the room thermostat demand cycle has been satisfied. (If the temperature select shunt is not installed, the default termination temperature will be 90°F.) If the room thermostat demand cycle terminates the cycle, the defrost cycle will be held until the next room thermostat demand cycle. If the coil sensor temperature is still below the selected termination temperature, the control will continue the defrost cycle until the cycle is terminated in one of the meth­ods mentioned above. If a defrost is terminated by time and the coil temperature did not remain above 35°F (2°C) for 4 minutes the control will go to the 34−minute Time/Temperature mode.
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