INSTALLATION INSTRUCTIONS

Transcription

1 ,1,_2008 Lennox industries inc. Dallas, Texas, USA INSTALLATION INSTRUCTIONS XC21 Series Units AIR CONDITIONER _) Technical 504,966M j!jj Publications Litho U.S.A. Supersedes 11/07 RETAIN THESE INSTRUCTIONS FOR FUTURE REFERENCE WARNING A CAUTION XC21 Outdoor Unit... 1 Shipping and Packing List... 1 Unit Dimensions... 2 General Information... 2 Setting the Unit... 3 Removing Panels... 4 Electrical... 5 Refrigerant Piping... 6 Flushing Existing Line Set and Indoor Coil... 9 Refrigerant Metering Device Manifold Gauge Set Service Valves Leak Testing Evacuating the System Start-up Refrigerant Charge Check Indoor Airflow before Charging Determining Charge Method Weigh in Charge Approach TXV Charge Subcooling TXV Charge Pre-Charge Maintenance Checks System Operation Maintenance Homeowner Information Checklists A IMPORTANT A IMPORTANT Check the unit for shipping damage and listed items below are intact. If damaged, or if parts are missing, immediately contact the last shipping carrier, Assembled outdoor unit 1 - Bushing used for low voltage wiring 2 - Isolation grommets (for liquid and vapor lines, see figure 14 on page 8 XC21 outdoor units use HFC-410A refrigerant. This unit must be installed with a matching indoor coil and line set as outlined in the Lennox Engineering Handbook. XC21 outdoor units are designed for use in thermal expansion valve (TXV) systems only. Refer to the Lennox Engineering Handbook for TXV kits which must be ordered separately. 04/08 IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII Page 1 504,966M IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII

2 39-1/2 DISCHARGE (1003) AIR t ELECTRICAL 35-1/2 (902) \ SUCTION LINE INLET LIQUID LINE INLET 47 (1194) T 18-1/2 4-1/2 f 1 SIDE VIEW 1 (25) ACCESS VIEW UNITSUPPORT FEET 16-7/8 (429) 8-3/4 26-7/8 (683) 3-3/4 (95) CONTACTOR OPERATION MONITOR \ RUN CAPACITOR DISCHARGE LINE VAPOR VALVE AND GAUGE VAPOR LINE LOW SWITCH - OUTDOOR FAN TWO-STAGE COMPRESSOR PLUG HIGH PRESSURE SWITCH (79) 30-3/4 (781) 4-5/8 (117) BASE WITH ELONGATED LEGS XC21 PARTS ARRANGEMENT These instructions are intended as a general guide and do not supersede national or local codes in any way. Consult authorities having jurisdiction before installation. When servicing or repairing HVAC components, ensure caps and fasteners are appropriately tightened. Table 1 lists torque values for typical service/repair items. Table 1. Torque Requirements 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 Page M 04/08

3 WARNING SLAB MOUNTING When installing unit at grade level, the top of the slab should be high enough above grade so that water from higher ground will not collect around the unit. The slab should have a slope tolerance as described in figure 2. If necessary for stability, anchor unit to slab as described in Stabilizing Unit on Uneven Surfaces on page 4. INSTALL UNIT LEVEL OR, IF ON A SLOPE, MAINTAIN SLOPE TOLERANCE OF 2 DEGREES (OR 2 INCHES PER 5 FEET [50 MM PER 1.5 M]) AWAY FROM BUILDING STRUCTURE. il BUILDING STRUCTURE MOUNTING_ / SLAB --T GROUND LEVEL CAUTION See Unit Dimensions for sizing mounting slab, platforms or supports. Refer to figure 1 for installation clearances. Figure 2. Slab Mounting at Ground Level ELEVATING THE UNIT These units are outfitted with elongated feet as illustrated in figure 3. If additional elevation is necessary, raise the unit by extending the length of the unit support feet. This may be done with 2" SCH 40 female threaded adapter. The specified coupling will fit snuggly into the recess portion of the feet. Use additional 2" SCH 40 male threaded adaptors which can be threaded into the female threaded adaptors to make additional adjustments to the level of the unit. NOTE - Keep the height of extenders short enough to ensure a sturdy installation with no more than a maximum height of six inches. If it is necessary to extend further, consider adifferent type dfield-fabricated frame work that is sturdy enough for greater heights. NOTES NOTES Base See NOTES Box NOTES: Service clearance of 30 in, (762 mm) must be maintained on one of the sides adjacent to the control box. Clearance to one of the other three sides must be 36 inches (914 mm), Clearance to one of the remaining two sides may be 12 in. (305 mm) and the final side may be 6 inches (152 mm). Clearance of 24 in. (610 mm) must be maintained between two units. Clearance required on top of unit of 48 in. (1219 mm). Figure 1. Installation Clearances Leg Detail 2" (50.Smm) SCH 40 Female Threaded Adapter Figure 3. Elevated Slab Mounting using Feet Extenders Page 3 XC21 SERIES

4 STABILIZING UNIT ON UNEVEN SURFACES To help stabilize an outdoor unit, some installations may require strapping the unit to the pad using brackets and anchors commonly available in the marketplace. CAUTION A IMPORTANT I With unit positioned at installation site, remove two side Iouvered panels to expose the unit base pan. Install the brackets as illustrated in figure 4 using conventional practices; replace the panels after installation is complete. ACCESS PANEL Remove and reinstall the access panel as described in figure 5. _WARNING Remove 4 screws to remove panel for accessing compressor and controls. Install by positioning panel with holes aligned; install screws and tighten. ROOF ONE BRACKET PER SIDE (MIN.); FOR EXTRA STABILITY, 2 BRACKETS PER SIDE, 2" FROM EACH CORNER. Figure 4. Installing Stabilizer Brackets (Slab Side Mounting) MOUNTING Install unit at a minimum of four inches above the surface of the roof. Care must be taken to ensure weight of unit is properly distributed over roof joists and rafters. Either redwood or steel supports are recommended. LOUVERED Figure 5. Access PANELS Panel Remove the Iouvered panels as follows: 1. Remove two screws; allow 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 as illustrated in figure 6, Detail B. 3. Move panel down until lip of upper tab clears the top slot in corner post as illustrated in figure 6, Detail A. Position and Install Panel--Position the panel almost parallel with the unit as illustrated in figure 7, Detail D with the "screw side" as close to the unit as possible. Then, in a continuous motion: Page M 04/08

5 Slightlyrotateandguidethe lipof toptab inwardas illustratedinfigure6,detailsaandc;thenupwardinto thetopslotofthehingecornerpost. Rotatepaneltoverticaltofullyengagealltabs. Holdingthe panel'shingedsidefirmlyin place,close theright-handsideofthepanel,aligningscrewholes. Whenpanelis correctlypositionedandaligned,inserthe screwsandtighten. 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. In the U,S.A., wiring must conform with current local codes and the current National Electrical Code (NEC). In Canada, wiring must conform with current local codes and the current Canadian Electrical Code (CEC). Refer to the furnace or blower coil installation instructions for additional wiring application diagrams and refer to unit nameplate for minimum circuit ampacity and maximum overcurrent protection size. 1, Install line voltage power supply to unit from a properly sized disconnect switch as illustrated in figure 8, 2, Ground unit at unit disconnect switch or to earth ground, B4 OUTDOOR FAN C5 6ROUNOI LI SCREW HOLES RED RED F250 _R L_ OLUE.,5.EEo *' jg--i.-; YELLOW LOW SPEED COMPRESSOR BLACK COMMON 24V CONTACT Detail A AI32 DIAGNOSTIC MODULE Detail B iiiiiiiiiii,i!,i! ROTATE IN THIS DIRECTION; THEN DOWN TO REMOVE PANEL Figure 6. Removing/Installing Louvered Panels (Details A, B and C) MAINTAIN MINIMUM PANEL ANGLE (AS CLOSE TO PARALLEL WITH THE UNIT AS POSSIBLE) WHILE INSTALLING PANEL. HOLD DOOR FIRMLY TO THE HINGED ANGLE MAY BE TOO SIDE TO MAINTAIN EXTREME FULLY_ENGAGED TABS PREFERRED ANGLE FOR INSTALLATION Detail D Figure 7. Removing/Installing Louvered Panels (Details D) /60/1 WARNING! - ELECTRIC SHOCK HAZARD. Can cause INJURY or DEATH. Unit must be grounded in accordance with national and local codes. NOTE - For use with copper conductors only. Refer to unit rating plate for minimum circuit ampacity and maximum over-current protection size. Figure 8. Field Wiring Diagram 3. Connect conduit to the unit via the bottom hole using the bushing conduit fitting provided. NO TE - Units are approved conductors. for use only with copper NOTE - 24V, Class II circuit connections are made in the low voltage junction box. See figure 9 on page 6 for field wiring diagram. A complete unit wiring diagram is located on the back side of the access panel. NOTE - For proper voltages, select thermostat wire gauge per the following chart: Table 2. Wire Run Lengths Wire run length AWG # Insulation type less than 100' (30m) 18 color-coded, temperature more than 100' (30m) 16 rating 35 C minimum 4. Install room thermostat (ordered separately) on an inside wall approximately in the center of the conditioned area and 5 feet (1.5 m) from the floor. It should not be installed on an outside wall or where it can be affected by sunlight, drafts or vibrations. 5. Install low voltage wiring from outdoor to indoor unit and from thermostat to indoor unit as illustrated in figure 9 on page 6. Page 5 XC21 SERIES

6 I RE_L_, YLW _ --. CBSI MV, CBX32MV INDO_ UNIT 661V,B6OV SIGNATURE _' I NOIX_ THERMOSTAT UNIT A92 _ TBI _ A2 _ - DIM27 i... _ _i _-... B_ _)I []Z} _ --. &-- --!'1! _L-,,--._;_---;-@I,, BGNo-- ---_-- KI-I COMPRESSOR REQ B_ FA_ SIGNATURESTAT 81N27 UNIT TB I _0 BK-_---,--- -[_- 660 THERMOSTAT CB29,CBSO INDOOR UNIT THERMOSTAT I_L-li_ <_)1 I _} _) i i... _ _)I _ Co)I DAG,C_ UNIT TBI INDOOR THE_T_T Fi i, I [ ]- _ 71 l F _ I -till SWITCH _ HRI CONTACTOR F _-_ I o Bi $4 PRESSURE HIGH S_(ITCH CONPRESDOR_ EDOI_NT COMPRESSOR CO_WTACTOR i i I BLUE i " Y2 BL "'--I IIF" -c _1 Illl'_-L "._ _,, I _'_ ' I _",...Z_ I I I I,_ ON A92 DO NOT CUT GNBOARD '951 JUMPER I IDATA_., I I FROM R TO O. IT IS USED FOR APPLICATIONS J '0 A"_I _RN 1 11 FOR CONDENSING UNITS / I I "Z'..-_ ' /,_.FORoGNUENSIMO URITA_PL_0,,I0_ u_ / I ICON _,_ F_0 APPLICATIONS. 1 _ A_ REMOVE DS TO Y I JOMPER _#_GN DOTE-FOR USE IITH COPPER CGNDDOTORS ONLY. AND REMOVE JUMPER BETWEEN "R" AND "_2" REFER TO UNIT RATING PLATE FOR MINIB _ L3 SOLENOID IS LOCATED IN COMPRESSOR. CIREUIT AupACITY AND _AXIMOM OVERCURRGNT COIL IS 2 VOC. CO NOT C_CT 24VAC PROTECTION SIZE TO COIL TE_INALS. /2_ REFER TO COMPRESSORIN UNIT FOR _ SII IS OPTIONAL L(_ AMBIENT SWITCH ACTUAL TERMINAL ARRANGEMENT WARNING- NOTE: MINIMUM TRANSFORMER REQUIRED IN /_ ELECTRIC SHOCK HAZARD.CAN CAUSE INJURY INDOOR UNIT-CO VA OR UEATH.UNIT MOST BE GROUNDED IN ACCORDANCE _ITH NATIONAL AND LOCAL CORES. _ INDICATES OPTIONAL COMPONENTS Z_ REMOVEJUMPERFOR TWO STAGE COOL _ LINE VOLTAGEFIELD INSTALLED ON A92 CUT GNDOA 14 -lumperfromdo -- _ ICLASS II VOLTAGE FIELD INSTALLED TO R, WHEN HUMIDITY CONTROL IS USED UE VARIABLE FAN MOTOR (B4) THERMOSTAT SECOND-STAGE COOLING CONNECTIONS The Lennox XC21 requires a two-stage room thermostat to operate properly, Y2 room thermostat wire--connect the Y2 room thermostat output to the Y2 input (blue) field connection wire at the outdoor unit. L Terminal Wiring--Connect the L terminal room thermostat output to the L input (brown) field connection wire at the outdoor unit, Y2 DC Solenoid Connector (DC SOL)IThe two-pin DC solenoid connector is connected at the factory to the compressor second-stage solenoid connector. No connections are required for this component, If the XC21 unit is being installed with a new indoor coil and/or line set, make the refrigerant connections as outlined in this section, If an existing line set and/or indoor coil is going to be used to complete the XC21 system, refer to this section, as well as the flushing section which follows M 04/08 Figure 9. Typical Wiring Diagram Page 6 Field refrigerant piping consists of liquid and vapor lines from the outdoor unit (sweat connections) to the indoor coil (flare or sweat connections). Use Lennox L15 (sweat, non-flare) series line sets, or use field-fabricated refrigerant lines as listed in table 3, NOTE - When installing refrigerant lines longer than 50 feet, contact Lennox Technical Support Product Applications for assistance. To obtain the correct information from Lennox, be sure to communicate the following points: Line set diameters for the unit being installed as listed in table 3, Model (XC21) and size of unit (e,g, -060), Model Table 3. Refrigerant Field Connections Liquid Line Vapor Line /8 in. 7/8 in -048 (10 mm) (22 mm) /8 in, 1-1/8 in. (10 mm) (29 mm) Line Sets Recommended Line Set Liquid Vapor L15 Line Line Line Sets 3/8 in. 7/8 in L15-65 (lomm) (22mm) 15ft-50ft. (4.6 m- 15 m) 3/8 in, 1-1/8 in. Field (10 mm) (29 mm) Fabricated

7 IMPORTANT How to install line sets on vertical runs is illustrated in figure 13 on page 8, To hang line set from joist or rafter, use either metal strapping material or anchored hear, J WIRE (Around TIE vapor INSTALLING REFRIGERANT LINE (NEW OR REPLACEMENT) If refrigerant lines are routed through a wall, seal and isolate the opening so vibration is not transmitted to the building, Pay close attention to line set isolation during installation of any HVAC system. When properly isolated from building structures (walls, ceilings, floors), the refrigerant lines will not create unnecessary vibration and subsequent sounds. Also, consider the following when placing and installing a high-efficiency outdoor unit: 1, Placement--Some localities are adopting sound ordinances based on the unit's sound level registered from the adjacent property, not from the installation property, Install the unit as far as possible from the property line. When possible, do not install the unit directly outside a window. Glass has a very high level of sound transmission, For proper placement of unit in relation to a window see example illustrated in figure 10, STRAPPING MATERIAL (Around vapor line only) METAL 8 FEET TAPE OR WIRE TIE SLEEVE Strap the vapor line to the joist or TAPE OR rafter at 8 feet intervals then strap WIRE TIE the liquid line to the vapor line. ROOF RAFTER _ F OO,OS O _._,,11 I111 II Figure 11. Refrigerant Line Sets: Installing Horizontal Runs ANCHORED HEAVY NYLON WIRE TIE Due to sound considerations, do not install unit directly in front of a window. "_ STRAP LIQUID LINE TO VAPOR LINE LIQUID Two 90 elbows installed in line set will reduce line set vibration. METAL VAPOR LINE - SLEEVE WRAPPED IN ARMAFLEX AUTOMOTIVE MUFFLER-TYPE HANGER WALL o _1_ I Figure 10. Outside Unit Placement and Installation 2, Line Set Isolation--This reference illustrates procedures, which ensure proper refrigerant line set isolation: How to install line sets on horizontal runs is illustrated in figure 11, How to to make a transition from horizontal to vertical is illustrated in figure 12, METAL VAPOR LINE- LINE SLEEVE WRAPPED IN ARMAFLEX X STRAP LIQUID LINE LINE TO VAPOR LIQUID Figure 12. Refrigerant Line Sets: Transition from Vertical to Horizontal Page 7 XC21 SERIES

8 OUTSIDE WALLlinesmust IMPORTANT notcontact -Refrigerant wall. VAPOR LINE LIQUID LINE BRAZING CONNECTION PROCEDURE WARNING NOTE- Similar installation practices should be used if line set is to be installed on exterior of outside wall. WOOD BLOCK Before brazing, remove the access panel as illustrated in figure 5 on page 4; then remove the narrow piping panel to prevent burning off the paint as illustrated in figure 15, Remove two screws and remove panel before brazing. VAPOR LINE WRAPPED WITH ARMAFLEX LIQUID Line set connection points. PIPING Refrigerant lines must not contact structure. P PIPE FIBERGLASS INSULATIOi' CVC C kulk Figure 13. Refrigerant Line Sets: Installing Vertical Runs (New Construction Shown) INSTALLING ISOLATION GROMMETS Locate the isolation grommets (provided). Slide grommets onto vapor and liquid lines. Insert grommets into piping panel to isolate refrigerant lines from sheet metal edges, Suction Line Figure 14. Isolation PIPING PANEL Grommets., Figure 15. Piping Panel Removal Cut ends of the refrigerant lines square (free from nicks or dents), Debur the ends. The pipe must remain round, do not pinch end of the line. Flow dry nitrogen through the refrigerant piping while brazing line set connections; this prevents carbon deposits (oxidation) buildup on the inside of the joints being brazed, Such buildup may restrict refrigerant flow through screens and metering devices, To do this: Flow regulated nitrogen (at 1 to 2 psig) through the refrigeration gauge set into the Schrader port connection on the vapor service valve and out of the Schrader port connection on the liquid service valve. (Metering device (TXV) will allow low pressure nitrogen to flow through the system.) While nitrogen is flowing, braze refrigerant line set to the indoor and outdoor units, IMPORTANT: The flow of nitrogen must have an escape path other than through the joint to be brazed. 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 HFC-410A refrigerant, 4, To protect components during brazing, wrap a wet cloth around the valve body and copper tube stub and use another wet cloth underneath the valve body to protect the base paint, Also, shield the light maroon R-410A sticker, 5, Braze the line set to the service valve, Page M 04/08

9 6 Installthermalexpansionvalve(soldseparatelyand whichisapprovedforusewithhfc-410arefrigerant) intheliquidlineattheindoorcoil A IMPORTANT NOTE - The tube end must stay bottomed in the fitting during final assembly to ensure proper seating, sealing and rigidity kwarning A IMPORTANT REQUIRED EQUIPMENT Equipment required to flush the existing line set and indoor coil: CAUTION two clean HCFC-22 recovery bottles, oilless recovery machine with pump-down feature, two gauge sets (one for HCFC-22; one for HFC-410A), FLUSHING PROCEDURE 1 Remove existing HCFC22 refrigerant using the following appropriate procedure as illustrated in figure 16: ff the existing outdoor unit is not equipped with shutoff valves, or if the unit is not operational AND you plan to use the existing HCFC 22 refrigerant to flush the system Disconnect all power to the existing outdoor unit Connect to the existing unit a clean recovery cylinder and the recovery machine according to the instructions provided with the recovery machine Remove all HCFC 22 refrigerant from the existing system Check gauges after shutdown to confirm that the entire system is completely void of refrigerant Disconnect the liquid and vapor lines from the existing outdoor unit ff the existing outdoor unit is equipped with manual shutoff valves AND you plan to use NEW HCFC 22 refrigerant to flush the system Start the existing HCFC 22 system in the cooling mode and close the liquid line valve Pump all of the existing HCFC 22 refrigerant back into the outdoor unit (It may be necessary to bypass the low pressure switches to ensure complete refrigerant evacuation.) When the low side system pressures reach 0 psig, close the vapor line valve Disconnect all power to the existing outdoor unit Check gauges after shutdown to confirm that the valves are not allowing refrigerant to flow back into the low side of the system Disconnect the liquid and vapor lines from the existing outdoor unit 2 Remove the existing outdoor unit Set the new HFC-410A unit and follow the brazing connection procedure which begins on the previous page to make line set connections DO NOT install the provided fixed orifice yet Make low voltage and line voltage connections to the new outdoor unit Do NOT turn on power to unit or open the outdoor unit service valves at this time 3 Remove the existing refrigerant flow control orifice or thermal expansion valve before continuing with flushing procedures Existing devices are not approved for use with HFC-410A refrigerant and may prevent proper flushing, Use a field-provided fitting to reconnect lines. Page 9 XC21 SERIES

10 Inverted HCFC-22 Cylinder (Contains clean HCFC-22 to be used for flushing) Low Pressure High Pressure XISTING INDOOR CO Existing Vapor Line XC21 UNIT Existing Liquid Line RECOVERY A- j CYLINDER Liquid Line Service Valve )I /--7- Inlet NOTE - The inverted HCFC-22 Discharge RECOVERY MACHINE Opened I "Z/' _ cylinder must contain at least the same amount of refrigerant as was recovered from the existing system. Closed A IMPORTANT 4. Remove the pressure tap valve cores from the XC21 unit's service valves. Connect an HCFC-22 cylinder with clean refrigerant to the vapor service valve. Connect the HCFC-22 gauge set to the liquid line valve, Connect a recovery machine with an empty recovery tank to the gauge set 5. Set the recovery machine for liquid recovery and start the recovery machine. Open the gauge set valves to allow the recovery machine to pull a vacuum on the existing system line set and indoor coil. 6. Invert the cylinder of clean HCFC-22 and open its valve to allow liquid refrigerant to flow into the system through the vapor line valve. Allow the refrigerant to pass from the cylinder and through the line set and the indoor coil before it enters the recovery machine, 7. After all of the liquid refrigerant has been recovered, switch the recovery machine to vapor recovery so that all of the HCFC-22 vapor is recovered. Allow the recovery machine to pull a vacuum on the system, NOTE - A single system flush should remove all of the mineral oil from the existing refrigerant lines and indoor coil. A second flushing may be done (using clean refrigerant) if insufficient amounts of mineral oil were removed during the first flush. Each time the system is flushed, you must allow the recovery machine to pull a vacuum on the system at the end of the procedure M 04/08 Figure 16. Flushing Connection Page Close the valve on the inverted HCFC-22 drum and the gauge set valves. Pump the remaining refrigerant out of the recovery machine and turn the machine off. 9. Use dry nitrogen to break the vacuum on the refrigerant lines and indoor coil before removing the recovery machine, gauges and HCFC-22 refrigerant drum. Reinstall pressure tap valve cores into XC21 service valves. 10. Install the expansion valve in the liquid line at the indoor coil. XC21 units are used in thermal expansion valve (TXV) systems only. See the indoor coil installation instructions and the Lennox Engineering Handbook for approved TXV match-ups and application information. Table 3 on page 6 lists liquid and vapor line sizes and corresponding line sets. Expansion valves equipped with Chatleff type fittings are available from Lennox. Refer to the Engineering Handbook for expansion valves for use with specific match-ups. Table 4. Indoor Expansion Valve Kits MODELS KIT NUMBERS XC21-024, L51 XC21-048, M02 A, IMPORTANT If you install an expansion valve with an indoor coil that includes a fixed orifice, remove the orifice before the expansion valve is installed as illustrated in figure17.

11 (Uncased Coil Shown) I -_ TWO PATCHPIECE PLATE ORIoF_CE (uncased coil ORIFICE only) HOUSING EXPANSION VALVE I (see note) TUBES X SCHRADER SERVICE PORT CAP VALVE SERVICE PORT [open to line set (Valve Shown when valve is closed (front Closed) seated)] Insert hex wrench here (VALVE frontseated) STEM CAP To indoor coil To outdoor coil ACCESS FITTING (no valve core) On smaller suction lines, bulb may be mounted on top or side-mounted (preferably at 3 o'clock position). On 5/8" and larger lines, mount bulb approximately at the 4 or 8 o'clock posb tions; never mount on bottom of line. o _!clock NOTE - If necessary, remove HCFC-22 flow control device (fixed orifice/check expansion valve) from existing line set before installing H FC-410A approved expansion valve and o-ring. Figure 17. Metering Device Installation Manifold gauge sets used with systems charged with HFC-410A refrigerant must be capable of handling the higher system operating pressures, The gauges should be rated for use with pressures of on the high side and a low side of 30" vacuum to 250 psi with dampened speed to 500 psi. Gauge hoses must be rated for use at up to 800 psi of pressure with a 4000 psi burst rating, The liquid line and vapor line service valves as illustrated in figures 18 and 19, and gauge ports are used for leak testing, evacuating, charging and checking charge, See table 1 on page 2 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. SERVICE PORT SERVICE PORT CAP SCHRADER VALVE To indoor coil To outdoor Figure 18. Front-Seated To Access Port: coil (Valve Shown Open) insert hex wrench here STEM SAP Liquid Line Service Valve 1. Remove service port cap with an adjustable wrench. 2. Connect gauge to the service port. 3. When testing is completed, replace service port cap, Tighten finger tight and then torque per table 1 on page 2. To Open Front-SeatedServiceValves: 1. Remove stem cap with an adjustable wrench, 2. Use a service wrench with a hex-head extension (3/16" for liquid-line valve sizes; 5/16" for vapor-line valve sizes) to backthe stem out counterclockwise as far as it will go, 3, Replace the stem cap. Tighten finger tight and then torque per table 1 on page 2. To Close Front-SeatedService Valves: 1, Remove the stem cap with an adjustable wrench, 2. Use a service wrench with a hex-head extension (3/16" for liquid-line valve sizes; 5/16" for vapor-line valve sizes) to turn the stem clockwise to seat the valve. Tighten it firmly, 3. Replace the stem cap. Tighten finger tight and then torque per table 1 on page 2. Page 11 XC21 SERIES

12 VAPOR LINE (BALL TYPE) SERVICE VALVE Ball-type service valve as illustrated in figure 19 functions the same way as the other valves but cannot be rebuilt; if one fails, replace with a new valve, 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, USE ADJUSTABLE WRENCH TO OPEN: ROTATE STEM COUNTER-CLOCKWISE 90. TO CLOSE: ROTATE STEM CLOCKWISE 90. To indoor coil BALL (Shown closed) STEM 4, Connect a cylinder of dry nitrogen with a pressure regulating valve to the center port of the manifold gauge set, 5, Adjust dry nitrogen pressure to 150 psig (1034 kpa), Open the valve on the high side of the manifold gauge set in order to pressurize the line set and the indoor unit. 6, 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 dry nitrogen and HFC-410A mixture, Correct any leaks and recheck, WARNING SERVICE PORT SCHRADER VALVE SERVICE PORT CAP STEM CAP Figure 19. Bali-Type Vapor To outdoor coil Line valve (Valve Closed,WARNING After the line set has been connected to the indoor and outdoor units, check the line set connections and indoor unit for leaks, WARNING I IMPORTANT LEAK TEST WITH ELECTRONIC LEAK DETECTOR 1, Connect an HFC-410A manifold gauge set high pressure hose to the vapor valve service port. (Normally, the high pressure hose is connected to the liquid line port; however, connecting it to the vapor port better protects the manifold gauge set from high pressure damage.) 2, With both manifold valves closed, connect the cylinder of HFC-410A refrigerant to the center port of the manifold gauge set. Open the valve on the HFC-410A cylinder (vapor only). 3. Open the high pressure side of the manifold to allow HFC-410A into the line set and indoor unit. Weigh in a trace amount of HFC-410A. [A trace amount is a maximum of 2 ounces (57 g) refrigerant or 3 pounds (31 kpa) pressure]. Close the valve on the HFC-410A cylinder and the valve on the high pressure side of the manifold gauge set, Disconnect the HFC-410A cylinder M 04/08 Page 12 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 vapor combine with refrigerant to produce substances that corrode copper piping and compressor parts, A IMPORTANT FACTORY CHARGE 1. Connect manifold gauge set to the service valve ports as follows: low pressure gauge to vapor line service valve

13 high 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 the 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. Attach the manifold center port hose to a dry nitrogen cylinder with pressure regulator set to 150 psig (1034 kpa) and purge the hose. Open the manifold gauge valves to break the vacuum in the line set and indoor unit, Close the manifold gauge valves. A. WARNING 7, Shut off the dry nitrogen cylinder and remove the manifold gauge hose from the cylinder. Open the manifold gauge valves to release the dry nitrogen from the line set and indoor unit, 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 HFC-410A 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 HFC-410A cylinder and remove the manifold gauge set, UNITS DELIVERED VOID OF CHARGE If the system is void of refrigerant, clean the system using the procedure described below, 1, Use nitrogen to pressurize the system and check for leaks, Repair all leaks. 2. Evacuate the system to remove as much of the moisture as possible. 3, Use nitrogen to break the vacuum and install the provided filter drier in the system. 4, Evacuate the system again, Then, weigh the appropriate amount of HFC-410A refrigerant (listed on unit nameplate) into the system. 5, Monitor the system to determine the amount of moisture remaining in the oil. It may be necessary to replace the filter drier several times to achieve the required dryness level. If system dryness is not verified, the compressor will fail in the future. 1, Rotate fan to check for frozen bearings or binding, 2, Inspect all factory- and field-installed wiring for loose connections. 3, After evacuation is complete, open the liquid line and vapor line service valves to release the refrigerant charge (contained in outdoor unit) into the system. 4, Replace the stem caps and tighten to the torque listed in the table 1 on page 2, 5, Check voltage supply at the disconnect switch. The voltage must be within the range listed on the unit's nameplate. If not, do not start the equipment until you have consulted the power company and the voltage condition has been corrected, 6, Set the thermostat for a cooling demand. Turn on power to the indoor blower and close the outdoor unit disconnect switch to start the unit. 7, Recheck voltage while the unit is running. Power must be within range shown on the nameplate. IMPORTANT This system uses HFC-410A refrigerant which operates at much higher pressures than HCFC-22. The provided liquid line filter drier is approved for use with HFC-410A. Do not replace it with components designed for use with HCFC-22. This unit is NOT approved for use with coils which use capillary tubes as a refrigerant metering device, Page13 XC21 SERIES

14 NOTE - Be sure that filters and indoor and outdoor coils are clean before testing. Check indoor airflow using the step procedures as illustrated in figure 20. Temp. DT ofair entering._ indoor coil F ' _5_ Wet-bulb F n 19 All temperatures are NDOOR! _ WET expressed in F COiL BULB 6 DRY BULB I Step 1. Determine the desired DT--Measure entering air temperature using dry bulb (A) and wet bulb (B). DT is the intersecting value of A and B in the table (see triangle). Step 2. Find temperature drop across coil--measure the coil's dry bulb entering and leaving air temperatures (A and C). Temperature Drop Formula: (TDrop) = A minus C. Step 3. Determine if fan needs adjustment--if the difference between the measured TDrop and the desired DT (TDrop-DT) is within +3, no adjustment is needed. See examples: Assume DT = 15 and A temp. = 72, these C temperatures would necessitate stated actions: C TDrop- DT = F ACTION = 4 Increase the airflow Figure 20. Checking Indoor Coil Airflow Guide = -1 (within +3 range) no change = -5 Decrease the airflow Step 4. Adjust the fan speed--see indoor unit instructions to increase/decrease fan speed. Changing air flow affects all temperatures; recheck temperatures to confirm that the temperature drop and DT are within +3. WHEN TO CHARGE? Warm weather best Can charge in colder weather CHARGE METHOD? Determine by: Outdoor ambient temperature REQUIREMENTS: Sufficient heat load in structure Indoor temperature between F (21-26 C) Manifold gauge set connected to unit Thermometers: to measure outdoor ambient temperature to measure liquid line temperature to measure vapor line temperature 1, Confirm proper airflow across coil per instructions as illustrated in figure 20 on page 14. 2, Check Liquid and Vapor line pressures and compare with Normal Operating Pressures listed in table 6 on page 16, NOTE - Table 6 on page 16 is a general guide. Expect minor pressures variations. Significant differences may mean improper charge or other system problem. 3. Recover the refrigerant from the unit, 4. Conduct leak check; evacuate as previously outlined, 5. Weigh in the unit nameplate charge plus any charge required for linsets differences from 15 feet, Table 5. Refrigerant Charge per Line Set Lengths Liquid Line Set Ounces per 5 feet (g per 1.5 m) adjust Diameter from 15 feet (4.6 m) line set* 3/8 in. (9.5 mm) 3 ounce per 5 ft. (85 g per 1.5 m) NOTE - *ff line length is greater than 15 ft. (4.6 m), add this amount, ff line length is less than!5 ft. (4.6 m), subtract this amounl Page M 04/08

15 A I:' F'ROACH TXV I, va,ueisgreaterthansho 1 >[ J approach), add refrigerant; if less than shown (liquid temp too close to ambient temp, low approach), remove refrigerant. ABOVE If refrigerant added or removed, retest to confirm that unit is properly charged 1. Confirm proper airflow across coil using figure 20 on page Compare unit pressures with Table 6, Normal Operating Pressures - Second Stage (High Capacity). 3. Set thermostat to call for heat (must have a cooling load between F (21-26 C) 4. Connect gauge set 5. When heat demand is satisfied, set thermostat to call for second stage (high capacity) cooling. 6. Allow temperatures and pressures to stabilize 7. Record outdoor ambient temperature: AMB o = 8. Record line temperature: LIQ o = 9. Subtract to determine approach (APP ): LIQ o. AMB o = App o 10. Compare results with table to the left. Second Stage (High Capacity) APP (Approach) Values(F:+/-1.0 ; [C: +/-0.6 ]) F ( C)* Any 10 (5.6) 10 (5.6) 6 (3.3) 9 (5.0) *Temperah,re nf air entering nl, dnnr cnil shown, remove equal sections of air intake panels and move If refrigerant; value is greater if less than than er coverings pressures sideways are needed until the to check liquid charge. pressure Block is in shown, add refrigerant, the above noted ranges. 1. Confirm proper airflow across coil using figure 20 on page Compare unit pressures with Table 6, Normal Operating Pressures - Second Stage (High Capacity). 3. Set thermostat to call for heat (must have a cooling load between F (21-26 C) 4. Connect gauge set 5. Measure outdoor ambient temperature 6. When heat demand is satisfied, set thermostat to call for second stage (high capacity) cooling. 7. Allow temperatures and pressures to stabilize. NOTE - ff necessary, block outdoor coil to maintain psig 8. Record line temperature: LIQo = 9. Record liquid line pressure; use value to determine saturation temperature (see table 7): SAT o= 10. Subtract to determine subcooling (SC ): SAT o. LIQo = SC o 11. Compare results with table to the left, Second Stage (High Capacity) SC I F (Subcooling) ( C)* -036 Values -042 (F:+/-1.0 ; -048 [C: -060+/-0.6 ])... IAny 4(22_ 8(44_ 10(56_ 7(39_ I *Temneratur_ nfair entering nutdnnr cnil Page 15 XC21 SERIES

16 Table 6. Normal Operating Pressures - Expansion Valve (TXV), IMPORTANT Normal Operating Pressures* XC F ( C)** Liquid Vapor Liquid Vapor Liquid Vapor Liquid Vapor First Stage (Low Capacity) 65 (18.3) (23.9) (29.4) (35.0) (40.6) (46.1) Second Stage (High Capacity) 65 (18.3) (23.9) (29.4) (35.0) (40.6) (46.1) * Typical pressures only, expressed in psig (liquid +/- 10 and vapor+/- 5 psig); indoor match up, indoor air quality, and indoorload will cause the pressuresto vary. ** Temperatureof air entering outdoorcoil. Table 7. HFC-410A Temperature ( F) - Pressure (Psig) F Psig F Psig F Psig F Psig F Psig F Psig F Psig F Psig TWO-STAGE COMPRESSOR The two-stage scroll compressor operates much like the The outdoor unit and indoor blower cycle on demand from standard scroll compressor with the exception the two step the room thermostat. When the thermostat blower switch compressor steps between low capacity and full capacity. is in the ON position, the indoor blower operates The steps occurwhen gas is bypassed through a vent port continuously. Page M 04/08

17 in the first suction pocket. This bypassing of gas allows the compressor to operate at low capacity if thermostat demand allows, creating a more cost effective and efficient compressor, Full capacity is achieved by blocking the vent port with a slider ring. The slider ring (vent port cover) is controlled by a 24VDC internal solenoid in the open position allowing low capacity. When energized the internal solenoid closes the slider ring, blocking the vent port and bringing the compressor to full capacity, Stepping can occur during a single thermostat demand as the motor runs continuously while the compressor steps from low to full capacity. LOW PRESSURE SWITCH XC21 units are equipped with a low pressure switch that is located in the vapor line to the compressor. The switch is a SPST, auto-reset switch that is normal closed. The switch opens at 40 psi and closes at 90 psi. VARIABLE SPEED CONDENSER FAN MOTOR The XC21 is equipped with a variable speed condenser fan motor that operates at two speeds. The thermostat controls the speed selection, FILTER DRIER A drier is factory-installed in each XC21 unit. A replacement drier is available from Lennox, Refer to Lennox Repair Part Program. HIGH PRESSURE SWITCH XC21 units are equipped with a high pressure switch that is located in the liquid line to the compressor. The switch is a SPST, manual-reset switch that is normal closed. The switch opens at 590 psi, LENNOX SYSTEM OPERATIONS MONITOR (LSOM) IMPORTANT The diagnostic indicator detects the most common fault conditions in the air conditioning 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 21 for the system operation monitor. LED FUNCTIONS Flash code number - corresponds to a number of LED flashes, followed by a pause, and then repeated. See table 8 for LED troubleshooting codes. Power LED (green)--indicates voltage within the range of 19-28VAC is present at the system monitor power connection. 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. p== w _4-- D D D Figure 22. LSOM ==rq -"'4"---- POWER LED _-Y y L R C O_-'-- ALERT LED _ TRIP LED THERMOSTAT SECOND-STAGE COOLING _" _,_CONNECTOR.25"SPADE,----"CONNECTOR(5) SOLENOID --! DATA OUTPUT CONNECTOR / The Lennox XC21 unit and system operation monitor (LSOM) require a two-stage room thermostat to operate properly, Wiring is described under Electrical on page 5, 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 as referenced in table 8 on page 18 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 communicate 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 THERMOSTATS 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, Page 17 XC21 SERIES

18 Status LED Condition Table 8. System Operation Monitor LED Troubleshooting Codes Status LED Description Status LED Troubleshooting Information Green LED ON Module has power 24VAC control power is present at the module terminal. Determine/verify that both R and C module terminals are connected and voltage is present Green LED OFF Module not powering up at both terminals. Red LED ON Red and Yellow LEDs Flashing System and compressor check out OK Thermostat demand signal Y1 is present, but compressor not running 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. R and C wires are reversed. 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. Simultaneous flashing, Indicates that the control circuit voltage is too low for operation. Yellow One Flash* Yellow Two Flashes* Long Run Time - Compressor is running extremely long run cycles System Pressure Trip - Discharge or suction pressure out of limits or compressor overloaded 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. 1 High head pressure. 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 three Short Cycling - Compressor is Flashes* running only briefly Yellow Four Flashes* Locked Rotor 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 low pressure switch is present, see Flash Code 1 information. 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 Five Flashes* Yellow Six Flashes* Open Circuit Open Start Circuit - Current only in run 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. 1 Run capacitor has failed. 2 Open circuit in compressor start wiring or connections. 3 Compressor start winding is damaged. Yellow Seven Open Run Circuit - Current Flashes* only in start circuit Yellow Eight Welded Contactor - Compres- Flashes* sor always runs Yellow Nine Low Voltage - Control circuit Flashes* <17VAC 1 Open circuit in compressor star[ wiring or connec_ons. 2 Compressor start winding is damaged. 1 Compressor contactor failed to open, 2 Thermostat demand signal not connected to module. 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 24MAC power from monitor; last code will display for 1 minute after monitor is powered on. Note: Upon Y2 signal detection and after 5 seconds, the LSOM module will send 24 VAC to the solenoid. Once the solenoid is fully energized, the LSOM module reduces voltage to between 4 to!8 VDC. Every!5 minutes the solenoid voltage will be increase to 24 volts for a few seconds to ensure solenoid valve is engaged until Y2 signal is no longer presenl M 04/08 Page 18

19 Y2DCSolenoidConnector(DCSOL)--The24VDC solenoid,whichis internal to thecompressor, willnot operateproperlyif24vacisappliedtothecompressor solenoidterminals.a voltmeterattachedto the DC SOL outputwill measure4-18vdcwhen the solenoidis energized, IMPORTANT,&WARNING 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 8 on page 18 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. Disconnect 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 8 on page 18 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 continues to monitor the compressor and system. When/if conditions return to normal, the alert code is turned off automatically, Maintenance and service must be performed by a qualified installer or service agency. At the beginning of each cooling season, check the system as follows: NOTE - Outdoor fan motor is prelubricated further lubrication is needed. and sealed. No 1, Clean and inspect the outdoor coil. The coil may be flushed with a water hose. Ensure the power is turned off before you clean the coil, 2, Check connecting lines and coils for signs of oil leaks, 3, Check wiring for loose connections. 4, Check for correct voltage at unit (unit operating), 5, Check amp-draw outdoor fan motor. Unit nameplate Actual NOTE - If owner reports insufficient cooling, the unit should be gauged and refrigerant charge checked, Refer to section on refrigerant charging section, INDOOR COIL 1, Clean coil, if necessary, 2. Check connecting lines and coils for signs of oil leaks, 3, Check condensate line and clean, if necessary. INDOOR UNIT 1. Clean or change filters, 2, Adjust blower speed for cooling, Measure the pressure drop over the coil to determine the correct blower CFM. Refer to the unit information service manual for pressure drop tables and procedure. 3, Check blower for accumulation of dirt or debris, 4. Check all wiring for loose connections 5, Check for correct voltage at unit (blower operating), 6, Check amp-draw on blower motor Unit nameplate Actual Page19 XC21 SERIES

20 TWO-STAGE MODULATION COMPRESSORS CHECK IMPORTANT Use this check-out procedure on page 22 to verify part-load and full-load capacity operation of two-stage modulation compressors, Tools required Refrigeration gauge set rated for HFC-410A use. Digital volt/amp meter Electronic temperature thermometer On-off toggle switch Procedure NOTE - Block outdoor coil to maintain a minimum of 375 psig during testing). 1, Turn main power OFF to outdoor unit, 2. Adjust room thermostat set point 5 F above the room temperature, 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), 7, Record all of the readings for the Y1 demand, 8, Close switch to energize Y2 demand, Verify power is going to compressor solenoid, 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 with the Y1 and Y2 demand, 11, If temperatures and pressures change in the direction noted in chart, the compressor is properly modulating from low to high capacity. If no amperage, pressures or temperature readings change when this test is performed, the compressor is not modulating between low and high capacity and replacement is necessary after a few checks, 12. After testing is complete, return unit to original set up M 04/08 Page 20 MAINTENANCE In order to ensure peak performance, your system must be properly maintained. Clogged filters and blocked airflow prevent your unit from operating at its most efficient level. 1, Air Filter--Ask your Lennox dealer to show you where your indoor unit's filter is located. It will be either at the indoor unit (installed internal or external to the cabinet) or behind a return air grille in the wall or ceiling. Check the filter monthly and clean or replace it as needed, 2, Disposable Filter--Disposable filters should be replaced with a filter of the same type and size. NOTE - If you are unsure about the filter required for your system, call your Lennox dealer for assistance. A IMPORTANT 3, Reusable Filter--Many indoor units are equipped with reusable foam filters. Clean foam filters with a mild soap and water solution; rinse thoroughly; allow filter to dry completely before returning it to the unit or grille. NOTE - The filter and all access panels must be in place any time the unit is in operation. 4. Indoor Unit--The indoor unit's evaporator coil is equipped with a drain pan to collect condensate formed as your system removes humidity from the inside air. Have your dealer show you the location of the drain line and how to check for obstructions. This would also apply to an auxiliary drain, if installed., IMPORTANT Outdoor Unit--Make sure no obstructions restrict airflow to the outdoor unit. Leaves, trash or shrubs crowding the unit cause the outdoor unit to work harder and use more energy, Keep shrubbery trimmed away from the unit and periodically check for debris which collects around the unit, When removing debris from around the unit, be aware of metal edges on parts and screws. Although special care has been taken to keep exposed edges to a minimum, physical contact with metal edges and corners while applying excessive force or rapid motion can result in personal injury. Cleaning of the outdoor unit's coil should be performed by a trained service technician. Contact your dealer and set up a schedule (preferably twice a year, but at least once a year) to inspect and service your air conditioning or heat pump system.

21 THERMOSTAT OPERATIONS Thermostat operations vary from one thermostat to another. The following provides general operation procedures. Refer to the user's information manual provided with your thermostat for specific operation details. Temperature Setting Levers Set the lever or dial to the desired temperature setpoints for both heating and cooling. Avoid frequent temperature adjustment; turning the unit off--then back on--before pressures can equalize will put unusual stress on the unit's compressor. Fan Switch In AUTO or INT (intermittent) mode, the blower operates only when the thermostat calls for heating or cooling. This mode is generally preferred when humidity control is a priority. The ON or CONT mode provides continuous indoor blower operation, regardless of whether the compressor or furnace is operating, This mode is required when constant air circulation or filtering is desired. System Switch Set the system switch for heating, cooling or auto operation, The auto mode allows the system to automatically switch from heating mode to cooling mode to maintain predetermined comfort settings. Temperature Indicator The temperature indicator displays the actual room temperature. Programmable Thermostats Your Lennox system may be controlled by a programmable thermostat. These thermostats provide the added feature of programmable time-of-day setpoints for both heating and cooling. Refer to the user's information manual provided with your thermostat for detailed programming and operation details. Preservice Check If your system fails to operate, check the following before calling for service: Check that all electrical disconnect switches are ON. Make sure the room thermostat Temperature Selector and System Switch (Heat, Cool, Auto) are properly set. Check for any blown fuses or tripped circuit breakers. Make sure unit access panels are in place. Make sure air filter is clean. If service is needed, locate and write down the unit model and serial numbers and have it handy before calling. OPTIONAL ACCESSORIES Optional accessories for the XC21 include the following (also, see Engineering Handbook for more details): Timed-off control Low ambient kit Page21 XC21 SERIES

22 !! _i _! _!!!!!!!!!_!!!!_!!_!_!!!!!!!!! Expected results during Y2 Unit Readings Y1 - First Stage demand (Toggle switch On) Y2 - Second Stage COMPRESSOR Voltage Amperage CONDENSER FAN MOTOR Same Higher Amperage TEMPERATURE Ambient Same or Higher Same Outdoor Coil Discharge Air Higher Compressor Discharge Line Higher Indoor Return Air Same Indoor Coil Discharge Air Lower PRESSURES Suction (Vapor) Liquid Lower Higher START UP CHECKS Refrigerant Type: First Stage: Rated Load Amps Second Stage: Rated Load Amps. Condenser COOLING Fan Full Load Amps MODE Suction Pressure: First Stage: Liquid Pressure: First Stage: Supply Air Temperature: First Stage: Temperature: Ambient: Actual Amps Rated Volts Actual Volts Actual Amps Rated Volts Actual Volts Actual Amps: First Stage Second Stage Second Stage: Second Stage: Second Stage: Return Air: System Refrigerant Charge (Refer to manufacturer's information on unit or installation instructions for required subcooling and approach temperatures.) Subcooling: A B SUBCOOLING Saturated Condensing Temperature (A) -- = minus Liquid Line Temperature (B) Approach: A B APPROACH Liquid Line Temperature (A) -- = minus Outdoor Air Temperature (B) Indoor Coil Temperature Drop (18 to 22 F) A B COIL TEMP DROP Return Air Temperature (A) -- = minus Supply Air Temperature (B) M 04/08 Page 22