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Instruction Manual for LENNOX models including: ML17XP1, Merit Series ML17XP1 Heat Pump Units, ML17XP1 Heat Pump Units, Heat Pump Units, Pump Units
2022-12-23 — To prevent serious injury or death: 1. Lock-out/tag-out before performing maintenance. 2. If system power is required (e.g., smoke detector.
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DocumentDocument©2022 Lennox Industries Inc. Dallas, Texas, USA THIS MANUAL MUST BE LEFT WITH THE HOMEOWNER FOR FUTURE REFERENCE 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. WARNING To prevent serious injury or death: 1. Lock-out/tag-out before performing maintenance. 2. If system power is required (e.g., smoke detector maintenance), disable power to blower, remove fan belt where applicable, and ensure all controllers and thermostats are set to the "OFF" position before performing maintenance. 3. Always keep hands, hair, clothing, jewelry, tools, etc. away from moving parts. INSTALLATION INSTRUCTIONS Merit® Series ML17XP1 Units HEAT PUMP 508263-01 6/2022 General This ML17XP1 outdoor heat pump 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 in-depth information, consult the Installation and Service Procedures manual, available on LennoxPros.com or through the Technical Support department at 800-453-6669. 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 15 in this instruction for information. STEP 1 SETTING THE UNIT Clearances 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. Page 1 UNIT DIMENSIONS - INCHES (MM) A B SIDE VIEW Model Number ML17XP1-018-230 ML17XP1-024-230 ML17XP1-030-230 ML17XP1-036-230 ML17XP1-042-230 ML17XP1-048-230 ML17XP1-060-230 A 28-1/4 (718) 28-1/4 (718) 28-1/4 (718) 32-1/4 (819) 32-1/4 (819) 32-1/4 (819) 32-1/4 (819) B 43-1/4 (1099) 43-1/4 (1099) 32-1/4 (819) 32-1/4 (819) 37-1/4 (946) 37-1/4 (946) 43-1/4 (1099) FIGURE 1. Unit Dimensions STEP 1 SETTING THE UNIT (Continued) Unit Placement 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 match-ups and expanded ratings, visit www.LennoxPros.com. Coils previously charged with HCFC-22 must be flushed. 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. IMPORTANT The Clean Air Act of 1990 bans the intentional venting of refrigerant (CFCs, HCFCs and HFCs) as of July 1, 1992. Approved methods of recovery, recycling or reclaiming must be followed. Fines and/or incarceration may be levied for noncompliance. 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 2 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 GROUND LEVEL FIGURE 3 IMPORTANT This model is designed for use in check / expansion valve systems only. An indoor expansion valve approved for use with HFC-410A refrigerant must be ordered separately and installed prior to operating the system. NOTE - An optional Unit Stand-Off Kit (94J45) is available for this unit. Black high-density polyethylene feet raise unit off of mounting surface away from damaging moisture. Four feet are furnished per order number. Page 2 STEP 2 REFRIGERANT PIPING 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. Polyol ester (POE) oils are used in Lennox 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 1. TABLE 1 REFRIGERANT LINE SET INCHES (MM) Model Valve Field Connections Liquid Vapor Line Line Recommended Line Set Liquid Line Vapor Line L15 Line Sets -018 -024 -030 3/8 in. 3/4 in. 3/8 in. 3/4 in. (10 mm) (19 mm) (10 mm) (19 mm) L15-41 15 ft. - 50 ft. (4.6 m - 15 m) -036 -042 -048 3/8 in. 7/8 in. 3/8 in. 7/8 in. (10 mm) (22 mm) (10 mm) (22 mm) L15-65 15 ft. - 50 ft. (4.6 m - 15 m) -060 3/8 in. (10 mm) 1-1/8 in. (28 mm) 3/8 in. (10 mm) 1-1/8 in. (28 mm) Field Fabricated NOTE - Some applications may require a field-provided 7/8" to 1-1/8" 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). 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 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. 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. 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. IMPORTANT Some scroll compressors have an internal vacuum protector that will unload scrolls when suction pressure goes below 20 psig. A hissing sound will be heard when the compressor is running unloaded. Protector will reset when low pressure in system is raised above 40 psig. DO NOT REPLACE COMPRESSOR. Page 3 STEP 2 REFRIGERANT PIPING (Continued) 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 4 Page 4 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 5 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 5 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 6 Page 6 STEP 2 REFRIGERANT PIPING Install Indoor Expansion Valve This outdoor unit is designed for use in systems that include an expansion valve metering device (purchased separately) at the indoor coil. See the ML17XP1 Product Specifications bulletin (EHB) for approved expansion valve kit match-ups and application information. The check 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 check/expansion valve in a manner that will provide access for future field service 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 to the right using the clamp and screws provided. MALE EQUALIZER LINE FITTING (SEE EQUALIZER LINE INSTALLATION FOR FURTHER DETAILS) VAPOR LINE LIQUID LINE 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 sembly. NOTE - Though it is preferred to have the sensing bulb installed on a horizontal run of the vapor line, installation 1/8 Turn on a vertical run of piping is acceptable if necessary. 11 12 1 NOTE - Confirm proper thermal contact between vapor 10 2 line and check/expansion bulb before insulating the 9 3 sensing bulb once installed. 2 - Connect the equalizer line from the check expansion 8 4 76 5 valve to the equalizer vapor port on the vapor line. Finger tighten the flare nut plus 1/8 turn (7 ft-lbs) as illustrated below. VAPOR LINE ON LINES SMALLER THAN 7/8", MOUNT SENSING BULB AT EITHER THE 3 OR 9 O'CLOCK POSITION. 12 BULB BULB FLARE SEAL CAP FLARE NUT VAPOR LINE OR COPPER FLARE SEAL BONNET MALE BRASS EQUALIZER LINE FITTING ON 7/8" AND LARGER LINES, MOUNT SENSING BULB AT 12 EITHER THE 4 OR 8 O'CLOCK POSITION. BULB BULB VAPOR LINE NOTE - NEVER MOUNT THE SENSING BULB ON BOTTOM OF LINE. FIGURE 7 Page 7 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 8 Page 8 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 RECOMMEND MINIMUM 3/8" HOSE A - Open both manifold valves and start the vacuum pump. 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 9 Page 9 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 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. 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. 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 10 Page 10 STEP 4 ELECTRICAL (Continued) High Voltage and Field Control Wiring The following illustration provides an example of control wiring connections when using a standard thermostat. ROUTING HIGH VOLTAGE, GROUND AND CONTROL WIRING HIGH VOLTAGE / GROUND WIRES Any excess high voltage field wiring should be trimmed and secured away from any low voltage field wiring. To facilitate a conduit, a cutout is located in the bottom of the control panel. Connect conduit to the control panel using a proper conduit fitting. TYPICAL CONTROL WIRING Install low voltage wiring from outdoor to indoor unit and from thermostat to indoor unit as illustrated. A - Run 24VAC control wires through hole with grommet. B - Make 24VAC thermostat wire connections to CMC1. WIRE RUN LENGTH AWG# INSULATION TYPE LESS THAN 100' (30 METERS) 18 TEMPERATURE RATING MORE THAN 100' (30 METERS) 16 35ºC MINIMUM. NOTE - Do not bundle any excess 24VAC control wires inside control panel. NOTE - For proper voltages, select thermostat wire (control wires) gauge per table below. Low Voltage Wiring (with Auxiliary Heat) Thermostat Indoor Unit Outdoor Unit HIGH VOLTAGE FIELD WIRING Thermostat LOW VOLTAGE FIELD WIRING Low Voltage Wiring Indoor Unit FACTORY WIRING Outdoor Unit R R POWER C C COMMON W1 W1 1ST. STAGE AUX. HEAT W2 W3 R POWER C COMMON W1 1ST. STAGE AUX. HEAT G G INDOOR BLOWER O O REVERSING VALVE Y1 Y1 COMPRESSOR (SOME CONNECTIONS MAY NOT APPLY. REFER TO SPECIFIC THERMOSTAT AND INDOOR UNIT.) R POWER C COMMON R POWER R C COMMON C E EMERGENCY HEAT W1 1ST. STAGE AUX. HEAT EMER. HEAT RELAY W1 OUTDOOR T'STAT W1 1ST. STAGE AUX. W2 HEAT W3 G G INDOOR BLOWER O O REVERSING VALVE Y1 Y1 COMPRESSOR (SOME CONNECTIONS MAY NOT APPLY. REFER TO SPECIFIC THERMOSTAT AND INDOOR UNIT.) NOTE - Wire tie provides low voltage wire strain relief and maintains separation of field-installed low and high voltage circuits. FIGURE 11 STEP 5 UNIT START-UP the voltage condition has been corrected. 6 - Connect manifold gauge set for testing and IMPORTANT If unit is equipped with a crankcase heater, it should charging. 7 - Set the thermostat for a cooling demand. Turn on power to the indoor indoor unit and close the be energized 24 hours before unit start-up to prevent outdoor unit disconnect switch to start the unit. 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 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 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 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 12 and 13 provide information on how to access and operate both angle- and ball-type service valves. Page 11 Torque Requirements When servicing or repairing heating, ventilating and air conditioning components, ensure the fasteners are appropriately tightened. Table 2 lists torque values for fasteners. TABLE 2 TORQUE REQUIREMENTS Parts Recommended Torque Service valve cap 8 ft.-lb. 11 NM Sheet-metal screws 16 in.-lb. 2 NM Machine screws #10 28 in.-lb. 3 NM Compressor bolts 90 in.-lb. 10 NM Gauge port seal cap 8 ft.-lb. 11 NM IMPORTANT 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 FIGURE 12 BALL (SHOWN CLOSED) VALVE STEM STEM CAP 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 13 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 87 6 43 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 76 4 5 FIGURE 14 Page 12 Checking Refrigerant Charge The ML17XP1 unit is factory-charged with enough HFC410A refrigerant to accommodate a 15-foot length of refrigerant piping. 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 ML17XP1 Installation and Service Procedures manual, which is available on LennoxPros.com. Defrost System This section addresses: · Emergency Heat · Defrost System Overview · Defrost Control Connections, Jumper Settings and Features · Operational Mode Overview (Calibration, Normal and Defrost) · Defrost Cycle Actuation EMERGENCY HEAT (AMBER LIGHT) An emergency heat function is designed into some room thermostats. This feature is applicable when isolation of the outdoor unit is required, or when auxiliary electric heat is staged by outdoor thermostats. When the room thermostat is placed in the emergency heat position, the outdoor unit control circuit is isolated from power and field-provided relays bypass the outdoor thermostats. An amber indicating light simultaneously comes on to remind the homeowner that he is operating in the emergency heat mode. Emergency heat is usually used during an outdoor unit shutdown, but it should also be used following a power outage if power has been off for over an hour and the outdoor temperature is below 50°F (10°C). System should be left in the emergency heat mode at least six hours to allow the crankcase heater sufficient time to prevent compressor slugging. DEFROST SYSTEM OVERVIEW The control monitors ambient temperature, outdoor coil temperature, and total run time to determine when a defrost cycle is required. The coil temperature probe is designed with a spring clip to allow mounting to the outside coil tubing. The location of the coil sensor is important for proper defrost operation. NOTE The demand defrost control accurately measures the performance of the system as frost accumulates on the outdoor coil. This typically will translate into longer running time between defrost cycles as more frost accumulates on the outdoor coil before the demand defrost control initiates defrost cycles. DEFROST CONTROL CONNECTIONS, JUMPER SETTINGS AND FEATURES Defrost Temperature Termination Jumper Settings (P1) The demand defrost control selections are: 50, 70, 90 and 100°F (10, 21, 32 and 38°C). The shunt termination pin is factory set at 50°F (10°C). If temperature shunt is not installed, default termination temperature is 90°F (32°C). Test Pins (P1) Function Placing the jumper on the field test pins (P1) allows the technician to: · Clear short cycle lockout · Clear five-strike fault lockout · Cycle the unit in and out of defrost mode · Place the unit in defrost mode to clear the coil Compressor Delay Mode (P5) The demand defrost control has a field-selectable function to reduce occasional sounds that may occur while the unit is cycling in and out of the defrost mode. When a jumper is installed on the DELAY pins, the compressor will be cycled off for 30 seconds going in and out of the defrost mode. Units are shipped with jumper installed on DELAY pins. NOTE The 30 second off cycle is NOT functional when jumpering the TEST pins. 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 (S87) This unit is equipped with a low pressure switch which is located on the suction line. The SPST, normally open pressure switch opens when suction line pressure falls below the factory setting of 25 ± 5 psig and closes when pressure rises at 40 ± 5 psig. Page 13 DEMAND DEFROST CONTROL (A108) DIAGNOSTIC LEDS The state (Off, On, Flashing) of two LEDs on the demand defrost control (DS1 [Red] and DS2 [Green]) indicate diagnostics conditions that are described in table 3. TABLE 3 DEMAND DEFROST CONTROL (A108) DIAGNOSTIC LEDS DS1 and DS2 System Status, Fault and Lockout Codes DS2 Green DS1 Red Type Condition/Code Possible Cause(s) Solution OFF OFF Status Power problem No power (24V) to demand defrost control terminals R and C or demand defrost control failure. 1.Check control transformer power (24V). 2.If power is available to demand defrost control and trol. Simultaneous SLOW Flash Alternating SLOW Flash Simultaneous FAST Flash Alternating FAST Flash Status Status Fault Fault ON ON Fault OFF SLOW Flash Fault OFF ON Lockout SLOW Flash OFF Fault ON OFF Lockout Normal operation 5-minute anti-short cycle delay Ambient Sensor Problem Coil Sensor Problem Demand Defrost Control Failure Low Pressure Fault Low Pressure Lockout High Pressure Fault High Pressure Lockout Unit operating normally or in standby mode. None required. Initial power up, safety trip, end of room thermostat demand. None required (jumper TEST pins to override) Sensor being detected open or shorted or out of temperature range. Demand defrost control will revert to time/temperature defrost operation. (System will still heat or cool). Sensor being detected open or shorted or out of temperature range. Demand defrost control will not perform demand or time/temperature defrost operation. (System will still heat or cool.) Indicates that demand defrost control has internal component failure. Cycle 24VAC power to demand defrost control. If code does not clear, replace demand defrost control. Restricted air flow over indoor or outdoor coil. Remove any blockages or restrictions from coils and/or fans. Check indoor and outdoor fan motor for proper current draws. Improper refrigerant charge in system. Check system charge using subcooling method. Improper metering device installed or incorrect operation of metering device. Check system operating pressures and compare to unit subcooling tables in this instruction or located on unit access panel. Incorrect or improper sensor location or connection to system. Make sure all pressure switches and sensors have secure connections to system to prevent refrigerant leaks or errors in pressure and temperature measurements. (Each fault adds 1 strike to that code's counter; 5 strikes per code = LOCKOUT) 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). Heat Pump Operation Your new Lennox heat pump has several characteristics that you should be aware of: · Heat pumps satisfy heating demand by delivering large amounts of warm air into the living space. This is quite different from gas- or oil-fired furnaces or an electric furnace which deliver lower volumes of considerably hotter air to heat the space. · Do not be alarmed if you notice frost on the outdoor coil in the winter months. Frost develops on the outdoor coil during the heating cycle when temperatures are below 45ºF (7ºC). An electronic control activates a defrost cy- cle lasting 5 to 15 minutes at preset intervals to clear the outdoor coil of the frost. · During the defrost cycle, you may notice steam rising from the outdoor unit. This is a normal occurrence. The thermostat may engage auxiliary heat during the defrost cycle to satisfy a heating demand; however, the unit will return to normal operation at the conclusion of the defrost cycle. 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. Page 14 · 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. 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. Extended Power Outage The heat pump is equipped with a compressor crankcase heater which protects the compressor during cold weather operation. If power to your unit has been interrupted for several hours or more, set the room thermostat selector to the EMERGENCY HEAT setting to obtain temporary heat without the risk of serious damage to the heat pump. In EMERGENCY HEAT mode, all heating demand is satisfied by auxiliary heat; heat pump operation is locked out. After a six-hour compressor crankcase warm-up period, the thermostat can be switched to the HEAT setting and normal heat pump operation may resume. 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. Page 15 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 - If your heat pump is matched with a gas- or oil-fired furnace for auxiliary heating, 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. He will turn on the air conditioner to check operating functions such as the startup and shutoff operation. He will also check for unusual noises or odors, and measure indoor/outdoor temperatures and system pressures as needed. He 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. ML17XP1 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 16