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Service Literature
The XPG20−036 is a high efficiency residential split−system
heat pump unit, which features a solar assisted DC motor,
two−step scroll compressor and HFC−410A refrigerant. The
XPG20 is designed for use with an expansion valve only
(approved for use with HFC−410A) in the indoor unit. This
manual is divided into sections which discuss the major
components, refrigerant system, charging procedure,
maintenance and operation sequence.
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 bat-
tered.
WARNING
Improper installation, adjustment, alteration, service
or maintenance can cause personal injury, loss of
life, or damage to property.
Installation and service must be performed by a
licensed professional installer (or equivalent) or a
service agency.
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Corp. 0907−L3
XPG20 SERIES UNITS
Table of Contents
1
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2
3
3
18
Page 1
DANGER
Shock Hazard
Remove all power at disconnect before
removing access panel.
XPG20 units use single-pole contac-
tors. Potential exists for electrical
shock resulting in injury or death.
Line voltage exists at all components
(even when unit is not in operation).
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VII Brazing Procedure
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VIII Diagrams and Operating Sequence
XPG20
26
34
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35
© 2009 Lennox Industries Inc.
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Summary of Contents for Lennox XPG20
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Page 1: Table Of Contents
DC motor, two−step scroll compressor and HFC−410A refrigerant. The XPG20 is designed for use with an expansion valve only (approved for use with HFC−410A) in the indoor unit. This manual is divided into sections which discuss the major components, refrigerant system, charging procedure, maintenance and operation sequence. -
Page 2: General
SPECIFICATIONS General Model No. XPG20−036 Data Nominal Tonnage (kW) 3 (10.6) Connections Liquid line (o.d.) − in. (mm) 3/8 (9.5) (sweat) Vapor line (o.d.) − in. (mm) 7/8 (22.2) Refrigerant R−410A charge furnished 12 lbs. 5 oz. (5.6 kg) Outdoor Net face area −... -
Page 3: I Application
All major components (indoor blower and coil) must be When panel is correctly positioned and aligned, insert the matched according to Lennox recommendations for the screws and tighten. compressor to be covered under warranty. Refer to the En- gineering Handbook for approved system matchups. - Page 4 AC FAN MOTOR AC FAN MOTOR MOUNT OUTDOOR FAN CONTACTOR SOLAR ASSIST DC MOTOR COUPLER DEFROST CONTROL SOLAR ASSIST DC MOTOR LENNOX SYSTEM OPERATION MONITOR (LSOM) RUN CAPACITOR SOLAR PANEL TERMINAL BLOCK VAPOR VALVE AND GAUGE PORT TWO−STAGE COMPRESSOR DISCHARGE LINE...
- Page 5 SCROLL FORM The scroll compressors in all XPG20 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.
- Page 6 TWO−STAGE OPERATION stage operation. The compressor will operate on first−stage until demand is satisfied or the indoor temperature reaches The two−stage scroll compressor operates like any stan- the thermostat set point calling for second−stage. dard scroll compressor with the exception the two−stage Second−stage (high capacity) is achieved by blocking the compressor modulates between first stage (low capacity bypass ports (figure 9 bypass ports closed) with a slider...
- Page 7 INTERNAL SOLENOID (L34) Procedure 1−. Turn main power "OFF" to outdoor unit. The internal unloader solenoid controls the two−stage op- 2−. Adjust room thermostat set point above (heating op- eration of the compressor by shifting a slide ring mecha- eration on heat pump) or below (cooling operation) the nism to open (low capacity) or close (high capacity), two room temperature 5ºF.
- Page 8 TABLE 1 Compressor Operation Y1 − Y2 − 1st-Stage Expected Results 2nd-Stage Unit Readings 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...
- Page 9 YELLOW tactors. BLACK C−Low Pressure Switch (S87) BLUE The XPG20 is equipped with an auto−reset low pressure motor switch which is located on the suction line. The switch shuts control module off the compressor when the suction pressure falls below FIGURE 11 the factory setting.
- Page 10 Initial Power Up Troubleshooting When line voltage is applied to the motor, there will be a If first or second stage thermostat call for cool is present large inrush of power lasting less than 1/4 second. This in- and the variable speed condenser fan motor does not ener- rush charges a bank of DC filter capacitors inside the con- gize, check voltage at the breaker box.
- Page 11 Replacement Disconnect DC solar motor wires and AC outdoor fan motor wires (highlted in figure 14). Follow the steps below if condenser fan motor replacement is necessary. Disconnect power at the main disconnect switch or main fuse box/breaker panel. FIGURE 14 Remove 4 screws on top of grille.
- Page 12 When replacing outdoor fan assembly make note of I−Drier fan location. See figure 16. A filter drier designed for the XPG20 is factory installed in the liquid line. The filter drier is designed to remove mois- ture and foreign matter, which can lead to compressor fail- ure.
- Page 13 Y2 room thermostat connection While the compressor is not running, LSOM will not power the solenoid, re- The Lennox system operation monitor (LSOM) is a 24 volt gardless of the state of Y2. If alert codes 1 or 9 (see...
- Page 14 TABLE 3 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 Module not powering up Determine/verify that both R and C module terminals are connected and voltage is present at both terminals.
- Page 15 K−Defrost System during the defrost cycle and 90 seconds after the termina- tion of defrost The demand defrost controller measures differential tem- when the average ambient sensor temperature is below peratures to detect when the system is performing poorly 15° F (−9°C) because of ice build−up on the outdoor coil.
- Page 16 Ambient and Coil Sensor Discharge Sensor 5750 7450 9275 11775 15425 19975 1000 1175 26200 1400 1700 34375 2025 46275 2500 3000 62700 3750 85300 4650 5825 10000 30000 50000 70000 90000 1000 2000 3000 4000 5000 6000 RESISTANCE (OHMS) RESISTANCE (OHMS) FIGURE 19 Sensor Locations...
- Page 17 4−. If the board recognizes five temperature sensor range Operational Description faults during a single (Y1) compressor demand, it re- The defrost control board has three basic operational verts to a lockout mode and displays the appropriate modes: normal, calibration, and defrost. code.
- Page 18 Actuation When the reversing valve is de−energized, the Test Mode When Y1 is energized and 24V power is be- Y1 circuit is energized, and the coil temperature is below ing applied to the board, a test cycle can be initiated by 35°F (2°C), the board logs the compressor run time.
- Page 19 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 34 MIN.
- Page 20 (ECM) that is coupled directly to the AC powered ECM mo- The solar module should be mounted in a location where it tor used in the XPG20 heat pump. This DC motor is wired will receive maximum sunlight throughout the year. When directly to the output of the single solar module.
- Page 21 LONGITUDE 130º W 120º W 110º W 100º W 90º W 80º W 70º W 50º 33º 45º 30º 40º 26º 35º 23º 30º 20º 25º 17º LATITUDE TILT ANGLE FIGURE 23 Solar module should be mounted according to manufactur- er’s recommendations.
- Page 22 CONDUIT ELBOWS CONDUIT (FIELD PROVIDED) TO EARTH GROUND PER (FIELD PROVIDED) NEC 690 SECTION V FIELD WIRING (FIELD PROVIDED) PIPING MODULE COMPLETE BOX AVAILABLE AS XPG20 CONTROL BOX CAT # 48W03 WEATHERPROOF ELECTRICAL ENCLOSURE (FIELD PROVIDED) CONTACTOR GROUND LUG WATERTIGHT FLEXIBLE...
- Page 23 MOTOR ALIGNMENT ADJUSTMENT OPERATIONS Before start up of the XPG20 unit, perform the procedure The DC motor is an electronically commutated brushless outlined in Figure 26. DC external rotor motor. The motor is rated at 1/5 HP and 8.5A FLA. The motor requires a 24 VDC nominal input (16 min to 28 max).
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Page 24: Refrigerant System
III−REFRIGERANT SYSTEM Separate liquid and suction service ports are provided at the service valves for connection of gauge manifold during charging procedure. Figure 27 shows XPG20 refrigerant IMPORTANT flow and gauge manifold connections. The Clean Air Act of 1990 bans the intentional vent- TABLE 7 ing of (CFC’s and HFC’s) as of July 1, 1992. - Page 25 A−Service Valves The ball valve is equipped with a service port with a factory− installed Schrader valve. A service port cap protects the Access the liquid line and vapor line service valves (figures Schrader valve from contamination and assures a leak− 28 and 29) and gauge ports are used for leak testing, eva- free seal.
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Page 26: Charging
IV−CHARGING IMPORTANT Units are factory charged with the amount of R410A refrig- erant indicated on the unit rating plate. This charge is Leak detector must be capable of sensing HFC refrigerant. based on a matching indoor coil and outdoor coil with 15 ft. (4.6m) line set. - Page 27 B−Evacuating Evacuating the system of non−condensables is critical for proper operation of the unit. Non−condensables are defined as any gas that will not condense under temperatures and pressures present during operation of an air conditioning system. Non−condensables and water suction combine with refrigerant to produce substances that corrode copper piping and compressor parts. MANIFOLD GAUGE SET HIGH A34000 1/4...
- Page 28 C−Charging TESTING CHARGE MANIFOLD TEMPERATURE GAUGE SET SENSOR OUTDOOR UNIT REFRIGERANT TO SUCTION TANK SERVICE VALVE CHARGE IN LIQUID PHASE DIGITAL SCALE TO LIQUID TEMPERATURE SENSOR LINE SERVICE (LIQUID LINE) VALVE Close manifold gauge set valves and connect the center hose to a cylinder of HFC−410A. Set for liquid phase charging. Connect the manifold gauge set’s low pressure side to the suction line service port.
- Page 29 80 24 24 24 23 23 22 22 22 20 19 18 17 16 15 Temperature of air entering indoor 78 23 23 23 22 22 21 21 20 19 18 17 16 15 14 coil ºF 76 22 22 22 21 21 20 19 19 18 17 16 15 14 13 74 21 21 21 20 19 19 18 17 16 16 15 14 13 12 72 20 20 19 18 17 17 16 15 15 14 13 12 11 10 70 19 19 18 18 17 17 16 15 15 14 13 12 11 10...
- Page 30 HEATING MODE INDOOR AIRFLOW CHECK Adding or Removing Refrigerant Blower airflow (CFM) may be calculated by energizing electric heat and measuring: IMPORTANT Temperature rise between the return air and supply air tem- peratures at the indoor coil blower unit, Mineral oils are not compatible with R410A. If oil Measuring voltage supplied to the unit, must be added, it must be a polyol ester oil.
- Page 31 SUBCOOLING 1−. Check the airflow as illustrated in Figure 31 to be sure the indoor airflow is as required. (Make any air flow adjustments before continuing with the following procedure.) 2−. Measure outdoor ambient temperature; determine whether to use cooling mode USE COOLING or heating mode to check charge.
- Page 32 TABLE 10 TABLE 11 HFC−410A Normal Operating Pressures XPG20−036 Matchups * Target Subcooling This table is used to perform maintenance checks and is INDOOR HEAT **Add Heating Cooling MATCH−UP PUMP (+5ºF) (+1ºF) charge not a procedure for charging the system. Minor variations in these pressures may be due to differences in installa- tions.
- Page 33 Table 12 HFC−410A Temperature/Pressure Chart Temperature Pressure Temperature Pressure Temperature Pressure Temperature Pressure °F Psig °F Psig °F Psig °F Psig 100.8 178.5 290.8 445.9 102.9 181.6 295.1 451.8 105.0 184.3 299.4 457.6 107.1 187.7 303.8 463.5 109.2 190.9 308.2 469.5 111.4 194.1...
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Page 34: Service And Recovery
5 − Check for correct voltage at unit (unit operating). R410 refrigerant. 6 − Check amp−draw on outdoor fan motor and compres- If the XPG20 system must be opened for any kind of ser- sor (high and low capacity). vice, such as compressor or filter drier replacement, you must take extra precautions to prevent moisture from en- 7 −... - Page 35 VIII−DIAGRAM / OPERATING SEQUENCE Page 35...
- Page 36 Sequence of Operation XPG20 4 − K1−1 closes, energizing the compressor and puts 240 volts into the outdoor fan motor through the normally NOTE − Solar motor will assist outdoor fan motor B1 closed fan relay contacts on the defrost board.