HVAC Supplier | LennoxPros
Installation Guide for LENNOX models including: ML18XC2 Outdoor Air Conditioner, ML18XC2, Outdoor Air Conditioner, Air Conditioner, Conditioner
Dec 11, 2023 — Cut ends of the refrigerant lines square (free from nicks or dents) and debur the ends. The pipe must remain round. Do not crimp end of the line. Remove service ...
Merit Series Small Split Systems ML18XC2 | Lennox Commercial
File Info : application/pdf, 17 Pages, 1.87MB
DocumentDocument©2023 Lennox Industries Inc. Dallas, Texas, USA THIS MANUAL MUST BE LEFT WITH THE HOMEOWNER FOR FUTURE REFERENCE General This ML18XC2 outdoor air conditioner with all-aluminum coil is designed for use with HFC-410A refrigerant only. This unit must be installed with an approved indoor air handler or coil. For AHRI Certified system match-ups and expanded ratings, visit www.LennoxPros.com. These instructions are intended as a general guide and do not supersede local codes in any way. Consult authorities having jurisdiction before installation. NOTICE! Charging information is given on the charging procedure sticker on the unit access panel. For more indepth information, consult the Installation and Service Procedures manual on LennoxPros.com or through the Technical Support department at 800-453-6669. STEP 1 SETTING THE UNIT Clearances INSTALLATION INSTRUCTIONS Merit® Series ML18XC2 Units AIR CONDITIONER 508277-01 9/2023 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 licensed professional HVAC installer or equivalent, or service agency. CAUTION As with any mechanical equipment, contact with sharp sheet metal edges can result in personal injury. Take care while handling this equipment and wear gloves and protective clothing. IMPORTANT: Special procedures are required for cleaning the all-aluminum coil in this unit. See page 16 in this instruction for information. See NOTES See NOTES See NOTES CONTROL 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 in. (914 mm). Clearance to one of the remaining two sides may be 12 in. (305 mm) and the final side may be 6 in. (152 mm). A clearance of 24 in. must be maintained between two units. 48 in. (1219 mm) clearance required on top of unit. NOTICE: Specific applications may require adjustment of the listed installation clearances to provide protection for the unit from physical damage or to avoid conditions which limit operating efficiency. (Example: Clearances may have to be increased to prevent snow or ice from falling on the top of the unit. Additional clearances may also be required to prevent air recirculation when the unit is installed under a deck or in another tight space.) FIGURE 1 Page 1 UNIT DIMENSIONS - INCHES (MM) A B SIDE VIEW FIGURE 2 TABLE 1 UNIT DIMENSIONS Model Numbers A ML18XC2-024-230A 28.25 (718) ML18XC2-036-230A 28.25 (718) ML18XC2-048-230A 32.25 (817) ML18XC2-060-230A 32.25 (817) B 29.25 (743) 33.25 (845) 33.25 (845) 43.25 (1099) STEP 1 SETTING THE UNIT (Continued) Unit Placement CAUTION Before attempting to perform any service or maintenance, turn the electrical power to unit OFF at disconnect switch. WARNING To prevent personal injury, as well as damage to panels, unit or structure, observe the following: While installing or servicing this unit, carefully stow all removed panels so that the panels will not cause injury to personnel, objects or nearby structures. Also, take care to store panels where they will not be subject to damage (e.g., being bent or scratched). While handling or stowing the panels, consider any weather conditions (especially wind) that may cause panels to be blown around and damaged. NOTICE! Roof Damage! This system contains both refrigerant and oil. Some rubber roofing material may absorb oil, causing the rubber to degrade. Failure to follow this notice could result in damage to roof surface. IMPORTANT This unit must be matched with an indoor coil as specified with AHRI. For AHRI Certified system matchups and expanded ratings, visit www.LennoxPros.com Coils previously charged with HCFC-22 must be flushed. IMPORTANT Exhaust vents from dryers, water heaters and furnaces should be directed away from the outdoor unit. Prolonged exposure to exhaust gases and the chemicals contained within them may cause condensation to form on the steel cabinet and other metal components of the outdoor unit. This will diminish unit performance and longevity. PLACEMENT INSTALL UNIT AWAY FROM WINDOWS TWO 90º ELBOWS INSTALLED IN LINE SET WILL REDUCE LINE SET VIBRATION FIGURE 3 SLAB MOUNTING 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. BUILDING STRUCTURE DISCHARGE AIR MOUNTING SLAB FIGURE 4 GROUND LEVEL STEP 2 REFRIGERANT PIPING Flushing Existing Line Set & Indoor Coil WARNING Refrigerant can be harmful if it is inhaled. Refrigerant must be used and recovered responsibly. Failure to follow this warning may result in personal injury or death. Page 2 IMPORTANT If this unit is being matched with an approved line set or indoor unit coil that was previously charged with mineral oil, or if it is being matched with a coil which was manufactured before January of 1999, the coil and line set must be flushed prior to installation. Take care to empty all existing traps. Polyvinyl ether (PVE) oils are used in Lennox variable-capacity units charged with HFC-410A refrigerant. Residual mineral oil can act as an insulator, preventing proper heat transfer. It can also clog the expansion device and reduce system performance and capacity. Failure to properly flush the system per this instruction and the detailed Installation and Service Procedures manual will void the warranty. Flush the existing line set per the following instructions. For more information, refer to the Installation and Service Procedures manual available on LennoxPros.com. CAUTION - DO NOT attempt to flush and re-use existing line sets or indoor coil when the system contains contaminants (i.e., compressor burn out). If a new line set is being installed, size the piping per table 2. WARNING When using a high pressure gas such as nitrogen to pressurize a refrigeration or air conditioning system, use a regulator that can control the pressure down to 1 or 2 psig (6.9 to 13.8 kPa). WARNING Polyol ester (POE) oils used with HFC-410A refrigerant absorb moisture very quickly. It is very important that the refrigerant system be kept closed as much as possible. DO NOT remove line set caps or service valve stub caps until you are ready to make connections. 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 fire and/ or an explosion, that could result in property damage, personal injury or death. LIQUID LINE FILTER DRIER INSTALLATION The provided filter drier must be field installed in the liquid line between the outdoor unit's liquid line service valve and the indoor coil's metering device (fixed orifice or TXV) as illustrated in figure 5. This filter drier must be installed to ensure a clean, moisture-free system. Failure to install the filter drier will void the warranty. A replacement filter drier is available from Lennox. See Brazing Connections page 6 for special procedures on brazing filter drier connections to the liquid line. Typical Liquid Line Filter Drier Installation BRAZE CONNECTION POINTS LIQUID LINE SERVICE VALVE OUTDOOR UNIT LINE LIQUID LINE FILTER DRIER FIGURE 5 LIQUID LINE Model Number ML18XC2-024-230 ML18XC2-036-230 ML18XC2-048-230 ML18XC2-060-230 TABLE 2 REFRIGERANT LINE SET INCHES (MM) Valve Size Connections Liquid Line Suction Line 3/8" (10 mm) 3/4" (19 mm) L15 Line Set Model L15-41-20 L15-41-30 L15-41-40 L15-41-50 Recommended Line Sets Line Set Length Catalog Number 20 feet (6.1 m) 30 feet (9.1 m) 40 feet (12.2 m) 50 feet (15.2 m) 89J56 89J57 89J58 89J59 L15-65-30 30 feet (9.1 m) 89J60 3/8" (10 mm) 7/8" (22 mm) L15-65-40 40 feet (12.2 m) 89J61 L15-65-50 50 feet (15.2 m) 89J62 3/8" (10 mm) 1-1/8" (29 mm) * Field-fabricated N/A N/A * Some applications may require a field-provided 1-1/8" to 7/8" adapter. NOTE - When installing refrigerant lines longer than 50 feet, refer to the Refrigerant Piping Design and Fabrication Guidelines manual available on LennoxPros.com (Corp. 9351-L9), or contact the Technical Support Department Product Application group for assistance. NOTE - For new or replacement line set installation, refer to Service and Application Note - Corp. 9112-L4 (C-91-4). Page 3 LINE SET IMPORTANT -- Refrigerant lines must not contact structure. INSTALLATION Line Set Isolation - The following illustrations are examples of proper refrigerant line set isolation: REFRIGERANT LINE SET -- TRANSITION FROM VERTICAL TO HORIZONTAL ANCHORED HEAVY NYLON WIRE TIE OR AUTOMOTIVE MUFFLER-TYPE HANGER AUTOMOTIVE MUFFLER-TYPE HANGER REFRIGERANT LINE SET -- INSTALLING VERTICAL RUNS (NEW CONSTRUCTION SHOWN) NOTE - Insulate liquid line when it is routed through areas where the surrounding ambient temperature could become higher than the temperature of the liquid line or when pressure drop is equal to or greater than 20 psig. IMPORTANT - Refrigerant lines must not contact wall OUTSIDE WALL SUCTION LINE LIQUID LINE WALL STUD STRAP LIQUID LINE TO SUCTION LINE NON-CORROSIVE METAL SLEEVE LIQUID LINE SUCTION LINE WRAPPED IN ARMAFLEX WOOD BLOCK BETWEEN STUDS WIRE TIE INSIDE WALL STRAP NON-CORROSIVE METAL SLEEVE WIRE TIE WOOD BLOCK WIRE TIE STRAP REFRIGERANT LINE SET -- INSTALLING HORIZONTAL RUNS To hang line set from joist or rafter, use either metal strapping material or anchored heavy nylon wire ties. 8 FEET (2.43 METERS) WIRE TIE (AROUND SUCTION LINE ONLY) STRAPPING MATERIAL (AROUND SUCTION LINE ONLY) FLOOR JOIST OR ROOF RAFTER TAPE OR WIRE TIE 8 FEET (2.43 METERS) NON-CORROSIVE METAL SLEEVE TAPE OR WIRE TIE FLOOR JOIST OR ROOF RAFTER STRAP THE SUCTION LINE TO THE JOIST OR RAFTER AT 8 FEET (2.43 METERS) INTERVALS THEN STRAP THE LIQUID LINE TO THE SUCTION LINE. SLEEVE SUCTION LINE WRAPPED WITH ARMAFLEX OUTSIDE WALL LIQUID LINE PVC PIPE CAULK FIBERGLASS INSULATION NOTE - Similar installation practices should be used if line set is to be installed on exterior of outside wall. FIGURE 6 Page 4 STEP 2 REFRIGERANT PIPING Removing Existing Indoor Metering Device 1A TYPICAL EXISTING FIXED ORIFICE REMOVAL PROCEDURE (UNCASED COIL SHOWN) DISTRIBUTOR TUBES LIQUID LINE ORIFICE HOUSING TEFLON® RING FIXED ORIFICE OR 1B TYPICAL EXISTING EXPANSION VALVE REMOVAL PROCEDURE (UNCASED COIL SHOWN) TWO-PIECE PATCH PLATE (UNCASED COIL ONLY) DISTRIBUTOR TUBES STUB END LIQUID LINE ORIFICE HOUSING CHECK EXPANSION VALVE TEFLON® RING BRASS NUT TEFLON® RING SENSING LINE DISTRIBUTOR ASSEMBLY REMOVE AND DISCARD WHITE TEFLON® SEAL (IF PRESENT) LIQUID LINE ASSEMBLY (INCLUDES STRAINER) A - On fully cased coils, remove the coil access and plumbing panels. DISTRIBUTOR ASSEMBLY EQUALIZER LINE LIQUID LINE ASSEMBLY WITH BRASS NUT B sembly. C - Using two wrenches, disconnect liquid line from liquid line ing. T cess. D - Remove and discard fixed orifice, valve stem assembly (if present) and Teflon® washer as illustrated above. E - Use a field-provided fitting to temporarily reconnect the liquid line to the indoor unit's liquid line orifice housing. MALE EQUALIZER LINE FITTING SENSING BULB VAPOR LINE LIQUID LINE A - On fully cased coils, remove the coil access and plumbing panels. B - Remove any shipping clamps from the liquid line and distributor assembly. C - Disconnect the equalizer line from the check expansion valve equalizer line fitting on the vapor line. 2 CONNECT GAUGES AND EQUIPMENT FOR FLUSHING PROCEDURE D - Remove the vapor line sensing bulb. E - Disconnect the liquid line from the check expansion valve at the liquid line assembly. CYLINDER CONTAINING CLEAN HCFC-22 TO BE USED FOR FLUSHING (Positioned to deliver liquid A refrigerant) GAUGE MANIFOLD F - Disconnect the check expansion valve from the liquid line orifice housing. Take care not to twist or damage distributor tubes during this process. G - Remove and discard check expansion valve and the two Teflon® 1 LOW HIGH rings. VAPOR LINE SERVICE VALVE NEW OUTDOOR H - Use a field-provided fitting to temporarily reconnect the liquid line to the indoor unit's liquid line orifice housing. EXISTING INDOOR UNIT UNIT B OPENED CLOSED 3FLUSHING LINE SET The line set and indoor unit coil must be flushed with at least the same amount of clean refrigerant that previously charged the system. Check the charge in the flushing cylinder before proceeding. VAPOR LIQUID LIQUID LINE SERVICE VALVE RECOVERY CYLINDER D TANK RETURN C INLET DISCHARGE RECOVERY MACHINE A - Set the recovery machine for liquid recovery and start the recovery machine. Open the gauge set valves to allow the recovery machine to pull a vacuum on the existing system line set and indoor unit coBil. B - Position the cylinder of clean HCFC-22 for delivery of liquid refrigerant 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 unit coil before it enters the recovery machine. C - After all of the liquid refrigerant has been recovered, switch the A - HCFC-22 cylinder with clean refrigerant (positioned to deliver liquid refrigerant) to the vapor service valve. recovery machine to vapor recovery so that all of the HCFC-22 vapor is recovered. Allow the recovery machine to pull the system B - HCFC-22 gauge set (low side) to the liquid line valve. down to 0. C - HCFC-22 gauge set center port to inlet on the recovery machine with an D - Close the valve on the inverted HCFC-22 drum and the gauge set empty recovery tank connected to the gauge set. valves. Pump the remaining refrigerant out of the recovery D - Connect recovery tank to recovery machine per machine instructions. machine and turn the machine off. FIGURE 7 Page 5 STEP 2 REFRIGERANT PIPING Brazing Procedures 1CUT AND DEBUR Cut ends of the refrigerant lines square (free from nicks or dents) and debur the ends. The pipe must remain round. Do not crimp end of the line. 2 CAP AND CORE REMOVAL Remove service cap and core from both the vapor and liquid line service ports. CUT AND DEBUR LINE SET SIZE MATCHES SERVICE VALVE CONNECTION COPPER TUBE STUB SERVICE VALVE CONNECTION REDUCER SERVICE PORT CAP SERVICE PORT CORE SERVICE PORT CORE LIQUID LINE SERVICE VALVE SERVICE PORT CAP VAPOR LINE SERVICE VALVE LINE SET SIZE IS SMALLER THAN CONNECTION REFRIGERANT LINE DO NOT CRIMP SERVICE VALVE CONNECTOR WHEN PIPE IS SMALLER THAN CONNECTION 3 ATTACH THE MANIFOLD GAUGE SET FOR BRAZING LIQUID AND VAPOR LINE SERVICE VALVES Flow regulated nitrogen (at 1 to 2 psig) through the low-side refrigeration gauge set into the liquid line service port valve, and out of the vapor line service port valve. A - Connect gauge set low pressure side to liquid line service valve (service port). B - Connect gauge set center port to bottle of nitrogen with regulator. LOW HIGH USE REGULATOR TO FLOW NITROGEN AT 1 TO 2 PSIG. C - Remove core from valve in vapor line service port to allow nitrogen to escape. ATTACH GAUGES VAPOR SERVICE PORT MUST BE OPEN C TO ALLOW EXIT POINT FOR NITROGEN INDOOR UNIT VAPOR LINE VAPOR LINE SERVICE VALVE B OUTDOOR UNIT LIQUID LINE LIQUID LINE SERVICE VALVE NITROGEN A WHEN BRAZING LINE SET TO SERVICE VALVES, POINT FLAME AWAY FROM SERVICE VALVE. FIGURE 8 CAUTION Brazing alloys and flux contain materials which are hazardous to your health. Avoid breathing vapors or fumes from brazing operations. Perform operations only in well-ventilated areas. Wear gloves and protective goggles or face shield to protect against burns. Wash hands with soap and water after handling brazing alloys and flux. WARNING Danger of fire. Bleeding the refrigerant charge from only the high side may result in pressurization of the low side shell and suction tubing. Application of a brazing torch to a pressurized system may result in ignition of the refrigerant and oil mixture. Check the high and low pressures before applying heat. Page 6 4 WRAP SERVICE VALVES To help protect service valve seals during brazing, wrap water-saturated cloths around service valve bodies and copper tube stubs. Use additional water-saturated cloths underneath the valve body to protect the base paint. 5 FLOW NITROGEN Flow regulated nitrogen (at 1 to 2 psig) through the refrigeration gauge set into the valve stem port connection on the liquid service valve and out of the vapor valve stem port. See steps 3A, 3B and 3C on manifold gauge set connections. 6 BRAZE LINE SET Wrap both service valves with water-saturated cloths as illustrated here and as mentioned in step 4, before brazing to line set. Cloths must remain water-saturated throughout the brazing and cool-down process. LIQUID LINE SERVICE VALVE WHEN BRAZING LINE SET TO SERVICE VALVES, POINT FLAME AWAY FROM SERVICE VALVE. IMPORTANT -- Allow braze joint to cool. Apply additional water-saturated cloths to help cool brazed joint. Do not remove water-saturated cloths until piping has cooled. Temperatures above 250ºF will damage valve seals. WARNING FIRE, PERSONAL INJURY, OR PROPERTY DAMAGE may result if you do not wrap a water-saturated cloth around both liquid and suction line service valve bodies and copper tube stub while brazing the line set! The braze, when complete, must be quenched with water to absorb any residual heat. Do not open service valves until refrigerant lines and indoor coil have been leak-tested and evacuated. Refer to Installation and Service Procedures manual found on LennoxPros.com. WATER-SATURATED CLOTH LIQUID LINE VAPOR LINE SERVICE VALVE WHEN BRAZING LINE SET TO SERVICE VALVES, POINT FLAME AWAY FROM SERVICE VALVE. VAPOR LINE WATER-SATURATED CLOTH 7 PREPARATION FOR NEXT STEP After all connections have been brazed, disconnect manifold gauge set from service ports. Apply additional water-saturated cloths to both services valves to cool piping. Once piping is cool, remove all water-saturated cloths. FIGURE 8 (CONTINUED) Page 7 STEP 2 REFRIGERANT PIPING Install Indoor Expansion Valve This outdoor unit is designed for use in systems that use an expansion valve metering device (purchased separately) at the indoor coil. See the ML18XC2 Product Specifications bulletin (EHB) for approved expansion valve kit match ups. The expansion valve unit can be installed internal or external to the indoor coil. In applications where an uncased coil is being installed in a field-provided plenum, install the expansion valve in a manner that will provide access for field servicing of the expansion valve. Refer to below illustration for reference during installation of expansion valve unit. INDOOR EXPANSION VALVE INSTALLATION TWO PIECE PATCH PLATE (UNCASED COIL ONLY) DISTRIBUTOR TUBES (Uncased Coil Shown) LIQUID LINE ORIFICE HOUSING STUB END CHECK EXPANSION VALVE TEFLON® RING DISTRIBUTOR ASSEMBLY TEFLON® RING EQUALIZER LINE SENSING LINE 1/2 Turn 3 - Install one of the provided Teflon® rings around the stubbed end of the check expansion valve and lightly lubricate the connector threads and expose surface of the Teflon® ring with refrigerant oil. 11 12 10 9 1 2 3 4 - Attach the stubbed end of the check expansion valve to the liquid line orifice housing. Finger tighten and use an 8 76 4 5 appropriately sized wrench to turn an additional 1/2 turn clockwise as illustrated in the figure above, or tighten to 20 ft-lb. 5 - Place the remaining Teflon® washer around the other end of the check expansion valve. Lightly lubricate connector threads and expose surface of the Teflon® ring with refrigerant oil. 6 - Attach the liquid line assembly to the check expansion valve. Finger tighten and use an appropriately sized wrench to turn an additional 1/2 turn clockwise as illustrated in the figure above or tighten to 20 ft-lb. LIQUID LINE ASSEMBLY WITH BRASS NUT SENSING BULB INSTALLATION 1 - Attach the vapor line sensing bulb in the proper orientation as illustrated belowusing the clamp and screws provided. MALE EQUALIZER LINE FITTING (SEE EQUALIZER LINE INSTALLATION FOR FURTHER DETAILS) VAPOR LINE LIQUID LINE ON LINES SMALLER THAN 3/4", MOUNT SENSING BULB AT EITHER THE 1 OR 11 O'CLOCK POSITION. Sensing bulb insulation is required if mounted external to the coil casing. sensing bulb installation for bulb positioning. EQUALIZER LINE INSTALLATION 1 - Remove and discard either the flare seal cap or flare nut with copper flare seal bonnet from the equalizer line port on the vapor line as illustrated in the figure below. 2 - Remove the field-provided ON 3/4" AND LARGER LINES, MOUNT SENSING BULB AT EITHER THE 3 OR 9 O'CLOCK POSITION. sembly. NOTE - NEVER MOUNT THE SENSING BULB ON BOTTOM OF LINE. FLARE SEAL CAP FLARE NUT NOTE - Though it is preferred to have the sensing bulb installed on a horizontal run of the vapor line, installation OR COPPER FLARE SEAL BONNET on a vertical run of piping is acceptable if necessary. See figure to right for proper bulb orientation on vert- ical run of piping. MALE BRASS EQUALIZER LINE FITTING NOTE - Confirm proper thermal contact between vapor line and check/expansion bulb before insulating the sensing bulb once installed. 1/8 Turn VAPOR LINE 2 - Connect the equalizer line from the check expansion valve tothe equalizer vapor port on the vapor line. Finger tighten the flare nut plus 1/8 turn (7 ft-lbs) as illustrated to the right. 11 12 1 10 2 9 3 8 4 76 5 FIGURE 9 Page 8 STEP 3 LEAK TEST AND EVACUATION LEAK TEST LOW HIGH MANIFOLD GAUGE SET OUTDOOR UNIT B A NITROGEN TO VAPOR SERVICE VALVE NOTE - Position canister to deliver liquid refrigerant. HFC-410A 1CONNECT GAUGE SET A - Connect the high pressure hose of an HFC-410A manifold gauge set to the vapor valve service port. NOTE - Normally, the high pressure hose is connected to the liquid line port. However, connecting it to the vapor port better protects the manifold gauge set from high pressure damage. B - With both manifold valves closed, connect the cylinder of HFC-410A refrigerant to the center port of the manifold gauge set. NOTE - Later in the procedure, the HFC-410A container will be replaced by the nitrogen container. 2TEST FOR LEAKS After the line set has been connected to the indoor and outdoor units, check the line set connections and indoor unit for leaks. Use the following procedure to test for leaks: A - With both manifold valves closed, connect the cylinder of HFC-410A refrigerant to the center port of the manifold gauge set. Open the valve on the HFC-410A cylinder (vapor only). B - Open the high pressure side of the manifold to allow HFC-410A into the line set and indoor unit. Weigh in a trace amount of HFC-410A. [A trace amount is a maximum of two ounces (57 g) refrigerant or three pounds (31 kPa) 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. C - Connect a cylinder of nitrogen with a pressure regulating valve to the center port of the manifold gauge set. D - Adjust nitrogen pressure to 150 psig (1034 kPa). Open the valve on the high side of the manifold gauge set in order to pressurize the line set and the indoor unit. E - After a few minutes, open one of the service valve ports and verify that the refrigerant added to the system earlier is measurable with a leak detector. F - After leak testing, disconnect gauges from service ports. FIGURE 10 Page 9 STEP 3 LEAK TEST AND EVACUATION (Continued) 3 EVACUATION CONNECT GAUGE SET NOTE - Remove cores from service valves (if not already done). A - Connect low side of manifold gauge set with 1/4 SAE in-line tee to vapor line service valve B - Connect high side of manifold gauge set to liquid line service valve C - Connect available micron gauge connector on the 1/4 SAE in-line tee. D - Connect the vacuum pump (with vacuum gauge) to the center port of the manifold gauge set. The center port line will be used later for both the HFC-410A and nitrogen containers. NOTE ister to deliver liquid NITROGEN refrigerant. OUTDOOR UNIT A 1/4 SAE TEE WITH SWIVEL COUPLER 500 C MICRON GAUGE LOW MANIFOLD GAUGE SET TO VAPOR SERVICE VALVE HFC-410A B VACUUM PUMP TO LIQUID LINE SERVICE VALVE HIGH D 4 EVACUATE THE SYSTEM A - Open both manifold valves and start the vacuum pump. RECOMMEND MINIMUM 3/8" HOSE B - Evacuate the line set and indoor unit to an absolute pressure of 23,000 microns (29.01 inches of mercury). NOTE - During the early stages of evacuation, it is desirable to close the manifold gauge valve at least once. A rapid rise in pressure indicates a relatively large leak. If this occurs, repeat the leak testing procedure. NOTE - The term absolute pressure means the total actual pressure above absolute zero within a given volume or system. Absolute pressure in a vacuum is equal to atmospheric pressure minus vacuum pressure. C - When the absolute pressure reaches 23,000 microns (29.01 inches of mercury), perform the following: WARNING ! Close manifold gauge valves. Close valve on vacuum pump. Possible equipment damage. Turn off vacuum pump. Avoid deep vacuum operation. Do not use Disconnect manifold gauge center port hose from vacuum pump. compressors to evacuate a system. Attach manifold center port hose to a nitrogen cylinder with pressure Extremely low vacuum can cause internal regulator set to 150 psig (1034 kPa) and purge the hose. arcing and compressor failure. Damage Open manifold gauge valves to break the vacuum in the line set and indoor caused by deep vacuum operation will unit. void warranty. Close manifold gauge valves. D - 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. E - 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. F - When the absolute pressure requirement above has been met, disconnect the manifold hose from the vacuum pump and connect it to a cylinder of HFC-410A positioned to deliver liquid refrigerant. Open the manifold gauge valve 1 to 2 psig in order to release the vacuum in the line set and indoor unit. G - Perform the following: Close manifold gauge valves. 1/6 TURN Shut off HFC-410A cylinder. Reinstall service valve cores by removing manifold hose from service valve. Quickly install cores with core tool while maintaining a positive system pressure. 11 12 1 10 2 Replace stem caps and finger tighten them, then tighten an additional one-sixth (1/6) of a turn as illustrated. 9 8 76 3 4 5 FIGURE 11 Page 10 STEP 4 ELECTRICAL Circuit Sizing and Wire Routing In the U.S.A., wiring must conform with current local codes and the current National Electric Code (NEC). In Canada, wiring must conform with current local codes and the current Canadian Electrical Code (CEC). Refer to the furnace or air handler installation instructions for additional wiring application diagrams and refer to unit nameplate for minimum circuit ampacity and maximum overcurrent protection size. 24VAC TRANSFORMER Use the transformer provided with the furnace or air handler for low-voltage control power (24VAC - 40 VA minimum). WARNING Fire Hazard. Use of aluminum wire with this product may result in a fire, causing property damage, severe injury or death. Use copper wire only with this product. WARNING Failure to use properly sized wiring and circuit breaker may result in property damage. Size wiring and circuit breaker(s) per Product Specifications bulletin (EHB) and unit rating plate. WARNING Electric Shock Hazard. Can cause injury or death. Unit must be properly grounded in accordance with national and local codes. Line voltage is present at all components when unit is not in operation on units with single-pole contactors. Disconnect all remote electric power supplies before opening access panel. Unit may have multiple power supplies. IMPORTANT If unit is equipped with a crankcase heater, it should be energized 24 hours before unit start-up to prevent compressor damage as a result of slugging. ELECTROSTATIC DISCHARGE (ESD) Precautions and Procedures WARNING Electrostatic discharge can affect electronic components. Take care 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. Touch hand and all tools on an unpainted unit surface before performing any service procedure to neutralize electrostatic charge. SIZE CIRCUIT AND INSTALL SERVICE DISCONNECT SWITCH Refer to the unit nameplate for minimum circuit ampacity, and maximum fuse or circuit breaker (HACR per NEC). Install power wiring and properly sized disconnect switch. MAIN FUSE BOX/ BREAKER PANEL SERVICE DISCONNECT SWITCH INSTALL THERMOSTAT Install room thermostat (ordered separately) on an inside wall approximately in the center of the conditioned area and 5 feet (1.5m) from the floor. It should not be installed on an outside wall or where it can be affected by sunlight or drafts. THERMOSTAT 5 FEET (1.5M) NOTE - Units are approved for use only with copper conductors. Ground unit at disconnect switch or connect to an earth ground. NOTE - 24VAC, Class II circuit connections are made in the control panel. FIGURE 12 Page 11 UNIT LOW VOLTAGE CONNECTIONS C WIRE NUTS ACUTOUT WITH GROMMET B 24V CONTROL WIRES BLUE BLACK YELLOW HIGH VOLTAGE FIELD WIRING FACTORY WIRING LOW VOLTAGE (24V) FIELD WIRING WIRE RUN LENGTH LESS THAN 100' (30 METERS) MORE THAN 100' (30 METERS) AWG# INSULATION TYPE 18 TEMPERATURE RATING 16 35ºC MINIMUM. D TIGHTEN WIRE TIE A. Run 24VAC control wires through cutout with grommet. B. Run 24VAC control wires through wire tie. C. Make 24VAC control wire connections using field-provided wire nuts. D. Tighten wire tie to security 24V control wiring. NOTE - FOR PROPER VOLTAGES, SELECT THERMOSTAT WIRE (CONTROL WIRES) GAUGE PER TABLE ABOVE. NOTE - WIRE TIE PROVIDES LOW VOLTAGE WIRE STRAIN RELIEF AND MAINTAINS SEPARATION OF FIELD-INSTALLED LOW-AND HIGH-VOLTAGE CIRCUITS. NOTE - DO NOT BUNDLE ANY EXCESS 24VAC CONTROL WIRES INSIDE CONTROL BOX. FIGURE 13 24VAC Control Wiring Diagrams (Field Installed) EL280, EL295, EL296 THERMOSTAT SLP98, SL28UH, SL280DF THERMOSTAT ML18XC2 5 BLUE ML18XC2 5 BLUE CBA27 CBA38MV THERMOSTAT 2 ML18XC2 1 ML18XC2 RED BROWN 3 4 BLUE 5 Y2 BLUE THERMOSTAT Air handler shipped with jumpers installed between W1 and W2 1 and W2 and W3. R connection required for air conditioner with LSOM. Resistor kit 2 (CAT #47W97) required when connection ComfortSense 7000 with LSOM 2. 3 L connection wired on units with LSOM. 4 Remove jumper for 2-stage cooling. 5 Clip onboard Y1 to Y2 for 2-stage cooling. NOTE - Refer to furnace, blower coil and accessory instructions for additional wiring configurations with other optional controls. FIGURE 14. Typical Control Wiring Page 12 ML18XC2-024 ML18XC2-036 ML18XC2-048 START CAPACITOR GROUND LUG B4 OUTDOOR FAN (LEADED) 2 ORANGE-RUN BLACK-COMMON 31 PURPLECAPACITOR F C S87 LOW PRESSURE SWITCH S4 HIGH PRESSURE SWITCH B1 COMPRESSOR 2 C SR 10 L34 K1 COMPRESSOR 4 K31 POTENTIAL CONTACTOR RELAY 5 (OPTIONAL) C12 H DUAL CAPACITOR CRANKCASE THERMOSTAT K1-1 COMPRESSOR CONTACTOR L1 11 S11 D4 10 BLACK BLACK S40 5 K31 2 B4 FAN MOTOR R C B1 (LEADED) COMPRESSOR 2 S YELLOW RED 13 1 PURPLE OR BROWN ORANGE RED 12 C7 HR1 H RED C F C12 DUAL CAPACITOR L34 S4 K1 BLUE 230/60/1 CRANKCASE HEATER RED L2 EQUIPMENT GROUND 3 EL196E ML180E ML193E EL180E EL195E ML196E INDOOR UNIT TB1 R THERMOSTAT A2 R W W1 W2 G G YELLOW Y Y1 BLUE Y2 BLACK C C YELLOW BLUE BLACK SLP99V SL297V SL280V ML296V ML180V EL280E EL 296E SLP99 INDOOR UNIT A92 TB1 5 THERMOSTAT A2 W914 DS D R R W951 O H 6 W1 W1 W2 W2 G G Y1 Y1 4 Y2 Y2 C C K1-1 COMPRESSOR CONTACTOR RED L1 RED L2 EC MOTOR CONNECTION (ML18XC2-060) YELLOW Y1 BLUE S87 Y2 BLACK C YELLOW BLUE BLACK CBA25UH, CBA27UHE & CBA38MV INDOOR UNIT THERMOSTAT TB1 A2 R R 9 W3 W2 W2 W1 W1 7 G G DS O Y1 4 Y2 C H D 8 Y1 Y2 C EQUIPMENT GROUND 1 NOTEFOR USE WITH COPPER CONDUCTORS ONLY. REFER TO UNIT RATING PLATE FOR MINIMUM CIRCUIT AMPACITY AND MAXIMUM OVERCURRENT PROTECTION SIZE 2 REFER TO COMPRESSOR IN UNIT FOR ACTUAL TERMINAL ARRANGEMENT 3 WARNINGELECTRIC SHOCK HAZARD,CAN CAUSE INJURY OR DEATH.UNIT MUST BE GROUNDED IN ACCORDANCE WITH NATIONAL AND LOCAL CODES. 4 REMOVE JUMPER FOR TWO STAGE COOL 5 ON A92 CUT ONBOARD W914 JUMPER FROM D5 TO R, WHEN HUMIDITY CONTROL IS USED 6 ON A92 DO NOT CUT ONBOARD W951 JUMPER FROM R TO O. IT IS USED FOR APPLICATIONS FOR CONDENSING UNITS 7 FOR CONDENSING UNIT APPLICATIONS USE R TO O JUMPER. REMOVE IN HEAT PUMP APPLICATIONS 8 REMOVE DS TO Y1 JUMPER WHEN HUMIDITY CONTROL IS USED 9 WHEN TWO STAGE THERMOSTAT IS USED, CONNECT SECOND STAGE HEAT BULB TO TERMINAL "W2", AND REMOVE JUMPER BETWEEN "R" AND "W2" 10 L34 SOLENOID IS LOCATED IN COMPRESSOR. COIL IS 24VDC. DO NOT CONNECT 24VAC TO COIL TERMINALS 11 S11 IS OPTIONAL LOW AMBIENT SWITCH 12 OPTIONAL HARD START KIT MAY BE REQUIRED ON APPLICATIONS WHERE VOLTAGES ARE LESS THAN 230 VOLT KIT ICLUDES K31 AND C7 WITH ALL NECESSARY WIRING. 13 S40 AND HRI ARE USED ON 048 AND 060 UNITS ONLY NOTEIF ANY WIRE IN THIS APPLIANCE IS REPLACED,IT MUST BE REPLACED WITH WIRE OF LIKE SIZE, RATING, INSULATION THICKNESS, AND TERMINATION. NOTE-MINIMUM TRANSFORMER REQUIRED IN INDOOR UNIT-40 VA LINE VOLTAGE FIELD INSTALLED CLASS II VOLTAGE FIELD WIRING DENOTES OPTIONAL COMPONENTS LENNOX ML18XC2-024 ML18XC2-036 COOLING CONDENSING ML18XC2-048 ML18XC2-060 Supersedes C 2011 FIGURE 15. Typical Field Wiring Litho U.S.A. Page 13 STEP 5 UNIT START-UP IMPORTANT If unit is equipped with a crankcase heater, it should be energized 24 hours before unit start-up to prevent compressor damage as a result of slugging. 1 - Rotate fan to check for 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 valve stems to release the refrigerant charge (contained in outdoor unit) into the system. 4 - Replace the stem caps and tighten to the value listed in table 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 with the power company and the voltage condition has been corrected. 6 - Connect manifold gauge set for testing and charging. 7 - Set the thermostat for a cooling demand. Turn on power to the indoor indoor unit and close the outdoor unit disconnect switch to start the unit. 8 - Recheck voltage while the unit is running. Power must be within range shown on the unit nameplate. 9 - Check system for sufficient refrigerant using the procedures outlined under Checking Refrigerant Charge. OPERATING MANIFOLD GAUGE SET AND SERVICE VALVES The liquid and vapor line service valves are used for removing refrigerant, flushing, leak testing, evacuating, checking charge and charging. Each valve is equipped with a service port which has a factory-installed valve stem. Figures 14 and 15 provide information on how to access and operate both angle- and ball-type service valves. Torque Requirements When servicing or repairing heating, ventilating and air conditioning components, ensure the fasteners are appropriately tightened. Table 3 lists torque values for fasteners. TABLE 3 TORQUE REQUIREMENTS Parts Recommended Torque Service valve cap 8 ft.-lb. 11 NM Sheet-metal screws 16 in.-lb. Machine screws #10 28 in.-lb. 2 NM 3 NM Compressor bolts 90 in.-lb. Gauge port seal cap 8 ft.-lb. 10 NM 11 NM IMPORTANT To prevent stripping of the various caps used, the appropriately sized wrench should be used and fitted snugly over the cap before tightening. Using Manifold Gauge Set When checking the system charge, only use a manifold gauge set that features low loss anti-blow back fittings. Manifold gauge set used with HFC-410A refrigerant systems must be capable of handling the higher system operating pressures. The gauges should be rated for use with pressures of 0 - 800 psig on the high side and a low side of 30" vacuum to 250 psig with dampened speed to 500 psi. Gauge hoses must be rated for use at up to 800 psig of pressure with a 4000 psig burst rating. OPERATING BALL-TYPE SERVICE VALVE 1 - Remove stem cap with an appropriately sized wrench. 2 - Use an appropriately sized wrench to open. To open valve, rotate stem counterclockwise 90°. To close, rotate stem clockwise 90°. TO OPEN, ROTATE STEM COUNTERCLOCKWISE 90°. TO CLOSE, ROTATE STEM CLOCKWISE 90°. SERVICE PORT SERVICE PORT CORE SERVICE PORT CAP BALL (SHOWN CLOSED) VALVE STEM STEM CAP FIGURE 16 OPERATING ANGLE-TYPE SERVICE VALVE 1 - Remove stem cap with an appropriately sized wrench. 2 - Use a service wrench with a hex-head extension (3/16" for liquid line valve sizes and 5/16" for vapor line valve sizes) to back the stem out counterclockwise as far as it will go. SERVICE PORT CAP SERVICE PORT CORE (VALVE STEM SHOWN OPEN) INSERT HEX WRENCH HERE STEM CAP ANGLE-TYPE SERVICE VALVE (BACK-SEATED OPENED) When service valve is OPEN, the service port is open to line set, indoor and outdoor unit. (VALVE STEM SHOWN CLOSED) INSERT HEX WRENCH HERE ANGLE-TYPE SERVICE VALVE (FRONT-SEATED CLOSED) When service valve is CLOSED, the service port is open to the line set and indoor unit. NOTE - A label with specific torque requirements may be affixed to the stem cap. If the label is present, use the specified torque. FIGURE 17 Page 14 ACCESS SERVICE PORT A service port cap protects the service port core from contamination and serves as the primary leak seal. 1 - Remove service port cap with an appropriately sized wrench. 2 - Connect gauge set to service port. 3 - When testing is completed, replace service port cap and tighten as follows: With torque wrench, finger tighten and torque cap per table 2. 1/6 TURN Without torque wrench, finger tighten and use an appropriately sized wrench to turn an additional 1/6 turn clockwise. 11 12 10 1 2 Reinstall Stem Cap 9 3 87 6 4 5 Stem cap protects the valve stem from damage and serves as the primary seal. Replace the stem cap and tighten as follows: With torque wrench, finger tighten and then torque cap per table 2. Without torque wrench, fi en and use an appropriately sized wrench to turn an additional 1/12 turn clockwise. 1/12 TURN 11 12 10 1 2 9 3 8 7 6 4 5 FIGURE 18 Checking and Adding System Charge The ML18XC2 unit is factory-charged with enough HFC410A refrigerant to accommodate a 15-foot length of refrigerant piping. For refrigerant piping greater than 15 feet, calculate the additional charge using the table below. Then add the additional charge specified for the specific indoor coil match-up listed on the unit charging sticker. Charge should be checked and adjusted using the tables provided on the charging procedure sticker on the unit access panel. Detailed information is given in the ML18XC2 Installation and Service Procedures manual, which is available on LennoxPros.com. Refrigerant Charge per Line Set Length LIQUID LINE DIA. OUNCES PER 5 FEET (G PER 1.5 M) ADJUST FROM 15 FEET (4.6 M) LINE SET* 3/8" (9.5 MM) 3 OUNCES PER 5' (85 G PER 1.5 M) *If line length is greater than 15 ft. (4.6 m), add this amount. If line length is less than 15 ft. (4.6 m), subtract this amount. NOTE Insulate liquid line when it is routed through areas where the surrounding ambient temperature could become higher than the temperature of the liquid line or when pressure drop is equal to or greater than 20 psig. High Pressure Switch (S4) This unit is equipped with a high pressure switch which is located on the liquid line. The SPST, normally closed pressure switch opens when liquid line pressure rises above the factory setting of 590 ± 15 psig and automatically resets at 418 ± 15 psig. Low Pressure Switch This unit is equipped with a low pressure switch which is located on the compressor suction line. The SPST, normally closed pressure switch opens when suction line pressure drops below the factory setting of 40 ± 5 psig and automatically resets at 95 ± 5 psig. Homeowners Information CAUTION Before attempting to perform any service or maintenance, turn the electrical power to unit OFF at disconnect switch. 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. The system should be inspected and serviced before each cooling and heating season by a licensed professional HVAC service technician (or equivalent). Homeowner Maintenance The following maintenance may be performed by the homeowner. · Contact a licensed professional HVAC technician to schedule inspection and maintenance appointments for your equipment before each heating and cooling season. · Check the indoor unit filter each month and replace the filter, if necessary. · Have your Lennox dealer show you where your indoor unit 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. Disposable filters should be replaced with a filter of the same type and size. · Check the indoor unit drain line for obstructions monthly. The indoor 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.) · Check the area around the outdoor unit monthly and remove any obstructions that may restrict airflow to the outdoor unit. This would include grass clippings, leaves, or papers that may have settled around the unit. · Trim shrubbery away from the unit and periodically check for debris which collects around the unit. · During the winter months, keep the snow level below the louvered panels. NOTE - The filter and all access panels must be in place any time the unit is in operation. If you are unsure about the filter required for your system, call your Lennox dealer for assistance. Page 15 IMPORTANT Sprinklers and soaker hoses should not be installed where they could cause prolonged exposure to the outdoor unit by treated water. Prolonged exposure of the unit to treated water (i.e., sprinkler systems, soakers, waste water, etc.) will corrode the surface of the steel and aluminum parts, diminish performance and affect longevity of the unit. Thermostat Operation See the thermostat homeowner manual for instructions on how to operate your thermostat. Pre-Service Check If your system fails to operate, check the following before calling for service: · Verify room thermostat settings are correct. · Verify that all electrical disconnect switches are ON. · Check for any blown fuses or tripped circuit breakers. · Verify unit access panels are in place. · Verify air filter is clean. If service is needed, locate and write down the unit model number and have it handy before calling. Professional Maintenance NOTICE ! Failure to follow instructions will cause damage to the unit. This unit is equipped with an aluminum coil. Aluminum coils may be damaged by exposure to solutions with a pH below 5 or above 9. The aluminum coil should be cleaned using potable water at a moderate pressure (less than 50psi). If the coil cannot be cleaned using water alone, Lennox recommends use of a coil cleaner with a pH in the range of 5 to 9. The coil must be rinsed thoroughly after cleaning. In coastal areas, the coil should be cleaned with potable water several times per year to avoid corrosive buildup (salt). Your heating and air conditioning system should be inspected and maintained twice each year (before the start of the cooling and heating seasons) by a licensed professional HVAC technician. You can expect the technician to check the following items. These checks may only be conducted by a licensed professional HVAC technician. Outdoor Unit 1 - Inspect component wiring for loose, worn or damaged connections. Also check for any rubbing or pinching of wires. Confirm proper voltage plus amperage of outdoor unit. 2 - Check the cleanliness of outdoor fan and blade condition (cracks) and clean or replace them, if necessary. 3 - Inspect base pan drains for debris and clean as necessary. 4 - Inspect the condition of refrigerant piping and confirm that pipes are not rubbing copper-tocopper. Also, check the condition of the insulation on the refrigerant lines. Repair, correct, or replace as necessary. 5 - Test capacitor. Replace as necessary. 6 - Inspect contactor contacts for pitting or burn marks. Replace as necessary. 7 - Check outdoor fan motor for worn bearings/ bushings. Replace as necessary. 8 - Inspect and clean outdoor coils, if necessary and note any damage to coils or signs of leakage. Indoor Unit (Air Handler or Furnace) 1 - Inspect component wiring for loose, worn or damaged connections. Confirm proper voltage plus amperage of indoor unit. 2 - Inspect and clean or replace air filters in indoor unit. 3 - Check the cleanliness of indoor blower and clean blower, if necessary. 4 - Inspect the indoor coil drain pans and condensate drains for rust, debris, obstructions, leaks or cracks. Pour water in pans to confirm proper drainage from the pan through to the outlet of the pipe. Clean or replace as necessary. 5 - Inspect and clean indoor coil, if necessary. 6 - Inspect the condition of the refrigerant lines and confirm that pipes are not rubbing copper-tocopper. Also, ensure that refrigerant pipes are not being affected by indoor air contamination. Check condition of insulation on the refrigerant lines. Repair, correct, or replace as necessary. 7 - Inspect the duct system for leaks or other problems. Repair or replace as necessary. 8 - Check for bearing/bushing wear on indoor blower motor. Replace as necessary. 9 - Indoor unit service will also include inspection and cleaning of the burners, and a full inspection of the gas valve, heat exchanger and flue (exhaust) system. General System Test with System Operating 1 - Your technician should perform a general system test. They will turn on the air conditioner to check operating functions such as the startup and shutoff operation. They will also check for unusual noises or odors, and measure indoor/outdoor temperatures and system pressures as needed. They will check the refrigerant charge per the charging sticker information on the outdoor unit. 2 - Verify that system total static pressure and airflow settings are within specific operating parameters. 3 - Verify correct temperature drop across indoor coil. Page 16 ML18XC2 Start-Up and Performance Checklist Customer Indoor Unit Model Outdoor Unit Model Notes: Address Serial Serial START UP CHECKS Refrigerant Type: Rated Load Amps: Condenser Fan Full Load Amps Actual Amps Rated Volts Actual Amps: Actual Volts COOLING MODE Suction Pressure: Liquid Pressure: Supply Air Temperature: Ambient Temperature: Return Air: Temperature: 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) Page 17