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©2023 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.
STEP 1 – SETTING THE UNIT – Clearances
See NOTES
See
NOTES
See NOTES
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).
See
Clearance to one of the remaining two sides may be 12 in. (305
NOTES
mm) and the final side may be 6 in. (152 mm).
A clearance of 24 in. must be maintained between two units.
CONTROL
48 in. (1219 mm) clearance required on top of unit.
BOX
Page 1
INSTALLATION
INSTRUCTIONS
Merit
Series ML17XP1 Units
®
HEAT PUMP
508263-01
9/2023
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 expand-
ed 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 jurisdic-
tion 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 clean-
ing the all-aluminum coil in this unit. See page 15 in this
instruction for information.
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Related Manuals for Lennox Merit ML17XP1 Series
Summary of Contents for Lennox Merit ML17XP1 Series
- Page 1 INSTALLATION INSTRUCTIONS ©2023 Lennox Industries Inc. Merit Series ML17XP1 Units Dallas, Texas, USA ® HEAT PUMP 508263-01 9/2023 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.
- Page 2 IMPORTANT UNIT DIMENSIONS - INCHES (MM) 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.
-
Page 3: Step 2 - Refrigerant Piping
Polyol ester (POE) oils are used Refrigerant can be harmful if it is inhaled. Refrigerant in Lennox units charged with HFC-410A refrigerant. must be used and recovered responsibly. Residual mineral oil can act as an insulator, preventing Failure to follow this warning may result in personal proper heat transfer. - Page 4 STEP 2 – REFRIGERANT PIPING – (Continued) 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 HOUSING VALVE...
- Page 5 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 6 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 7 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.
-
Page 8: 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 9 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 liquid line service valve...
- Page 10 WARNING STEP 4 – ELECTRICAL – Circuit Sizing and Wire Routing Fire Hazard. Use of aluminum wire with this product may result in a fire, causing property damage, severe injury In the U.S.A., wiring must conform with current local codes and the current National Electric Code (NEC).
-
Page 11: Typical Control Wiring
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. - Page 12 Torque Requirements OPERATING ANGLE-TYPE SERVICE VALVE When servicing or repairing heating, ventilating and air 1 - Remove stem cap with an appropriately sized wrench. conditioning components, ensure the fasteners are appro- priately tightened. Table 2 lists torque values for fasteners. 2 - Use a service wrench with a hex-head extension (3/16"...
- Page 13 Test Pins (P1) Function Checking Refrigerant Charge Placing the jumper on the field test pins (P1) allows the The ML17XP1 unit is factory-charged with enough HFC- technician to: 410A refrigerant to accommodate a 15-foot length of refrig- • Clear short cycle lockout erant piping.
-
Page 14: Homeowners Information
• Have your Lennox dealer show you where your indoor nace which deliver lower volumes of considerably hotter unit filter is located. It will be either at the indoor unit air to heat the space. -
Page 15: Professional Maintenance
In coastal areas, the coil should be cleaned with any time the unit is in operation. If you are unsure about potable water several times per year to avoid corro- the filter required for your system, call your Lennox dealer sive buildup (salt). for assistance. -
Page 16: Start Up Checks
4 - Inspect the indoor coil drain pans and condensate 9 - If your heat pump is matched with a gas- or oil-fired drains for rust, debris, obstructions, leaks or cracks. furnace for auxiliary heating, indoor unit service Pour water in pans to confirm proper drainage from will also include inspection and cleaning of the the pan through to the outlet of the pipe.
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