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©2022 Lennox Industries Inc.
Dallas, Texas, USA
THIS MANUAL MUST BE LEFT WITH THE
HOMEOWNER FOR FUTURE REFERENCE
General
This ML17XC1 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 han-
dler or coil. For AHRI Certified system match-ups and ex-
panded 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 on LennoxPros.com or through the
Technical Support department at 800-453-6669.
STEP 1 – SETTING THE UNIT – Clearances
See
NOTES
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.)
See NOTES
See
NOTES
CONTROL
See NOTES
BOX
INSTALLATION
INSTRUCTIONS
Merit
Series ML17XC1 Units
®
AIR CONDITIONER
508254-01
4/2022
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.
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 clean-
ing the all-aluminum coil in this unit. See page 15 in this
instruction for information.
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.
FIGURE 1
Page 1
WARNING
CAUTION
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Related Manuals for Lennox Merit ML17XC1 Series
Summary of Contents for Lennox Merit ML17XC1 Series
- Page 1 INSTALLATION INSTRUCTIONS ©2022 Lennox Industries Inc. Merit Series ML17XC1 Units Dallas, Texas, USA ® AIR CONDITIONER 508254-01 4/2022 WARNING Improper installation, adjustment, alteration, service or maintenance can cause property damage, personal injury or loss of life. Installation and service must be...
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Page 2: Slab Mounting
IMPORTANT UNIT DIMENSIONS - INCHES (MM) 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. IMPORTANT Exhaust vents from dryers, water heaters and furnaces should be directed away from the outdoor unit. - Page 3 Polyvinyl ether (PVE) to a spark or open flame, can cause fire and/ oils are used in Lennox variable-capacity units charged or an explosion, that could result in property with HFC-410A refrigerant. Residual mineral oil can damage, personal injury or death.
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Page 4: Installation
LINE SET IMPORTANT — Refrigerant lines must not contact structure. INSTALLATION REFRIGERANT LINE SET — INSTALLING Line Set Isolation - The following illustrations are VERTICAL RUNS (NEW CONSTRUCTION SHOWN) examples of proper refrigerant line set isolation: NOTE - Insulate liquid line when it is routed through areas where the surrounding ambient temperature could become higher than the REFRIGERANT LINE SET —... - Page 5 STEP 2 – REFRIGERANT PIPING – Removing Existing Indoor Metering Device TYPICAL EXISTING FIXED ORIFICE TYPICAL EXISTING EXPANSION VALVE REMOVAL REMOVAL PROCEDURE PROCEDURE (UNCASED COIL SHOWN) (UNCASED COIL SHOWN) STUB END TWO-PIECE PATCH PLATE LIQUID LINE CHECK DISTRIBUTOR TUBES (UNCASED COIL ONLY) ORIFICE EXPANSION LIQUID LINE ORIFICE HOUSING...
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Page 6: Cap And Core Removal
STEP 2 – REFRIGERANT PIPING – Brazing Procedures CAP AND CORE REMOVAL CUT AND DEBUR Cut ends of the refrigerant lines square (free from nicks or dents) Remove service cap and core from and debur the ends. The pipe must remain round. Do not crimp end both the vapor and liquid line service of the line. -
Page 7: Braze Line Set
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. 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. - Page 8 STEP 2 – REFRIGERANT PIPING – Install Indoor Expansion Valve This outdoor unit is designed for use in systems that use either a fixed orifice (RFC) (included with outdoor unit), or expan- sion valve metering device (purchased separately) at the indoor coil. See the ML17XC1 Product Specifications bulletin (EHB) for approved expansion valve kit match ups.
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Page 9: Step 3 - Leak Test And Evacuation
STEP 3 – LEAK TEST AND EVACUATION LEAK TEST HIGH MANIFOLD GAUGE SET OUTDOOR UNIT TO VAPOR SERVICE VALVE NOTE - Position canister to deliver liquid refrigerant. NITROGEN HFC-410A CONNECT 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. -
Page 10: Evacuate The System
STEP 3 – LEAK TEST AND EVACUATION (Continued) EVACUATION HIGH 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 OUTDOOR MANIFOLD... -
Page 11: Electrostatic Discharge
STEP 4 – ELECTRICAL – Circuit Sizing and Wire Routing In the U.S.A., wiring must conform with current local codes WARNING and the current National Electric Code (NEC). In Canada, wiring must conform with current local codes and the cur- Fire Hazard. - Page 12 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 FIELD CONTROL WIRING Any excess high voltage field wiring should be THERMOSTAT INDOOR UNIT...
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Page 13: Step 5 - Unit Start-Up
Using Manifold Gauge Set STEP 5 – UNIT START-UP When checking the system charge, only use a manifold gauge set that features low loss anti-blow back fittings. IMPORTANT Manifold gauge set used with HFC-410A refrigerant sys- If unit is equipped with a crankcase heater, it should tems must be capable of handling the higher system oper- ating pressures. - Page 14 410A refrigerant to accommodate a 15-foot length of re- frigerant piping. For refrigerant piping greater than 15 • Have your Lennox dealer show you where your indoor feet, calculate the additional charge using the table below. unit filter is located. It will be either at the indoor unit...
- Page 15 (less than 50psi). If the coil cannot 7 - Inspect the duct system for leaks or other problems. be cleaned using water alone, Lennox recommends Repair or replace as necessary. use of a coil cleaner with a pH in the range of 5 to 9.
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Page 16: Start Up Checks
ML17XC1 Start-Up and Performance Checklist Customer Address Indoor Unit Model Serial Outdoor Unit Model Serial Notes: START UP CHECKS Refrigerant Type: Rated Load Amps: Actual Amps Rated Volts Actual Volts Condenser Fan Full Load Amps Actual Amps: COOLING MODE Suction Pressure: Liquid Pressure: Supply Air Temperature: Ambient Temperature: Return Air: Temperature:...