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INSTALLATION INSTRUCTIONS
4SCU23LX
This is a safety alert symbol and should never be ignored. When you see this symbol on labels or in manuals, be alert to
the potential for personal injury or death.
Installation and servicing of air conditioning equipment
can be hazardous due to internal refrigerant pressure
and live electrical components. Only trained and
qualified service personnel should install or service
this equipment. Installation and service performed by
unqualified persons can result in property damage,
personal injury, or death.
Sharp metal edges can cause injury. When installing
the unit, use care to avoid sharp edges.
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.
Manufactured By
Allied Air Enterprises LLC
A Lennox International, Inc. Company
215 Metropolitan Drive
West Columbia, SC 29170
508296-01
This manual must be left with the homeowner for future reference.
WARNING
WARNING
Variable Capacity Air Conditioner
Table of Contents
General ........................................................................2
Installation ...................................................................2
Refrigerant Piping ........................................................4
Electrical - Circuit Sizing and Wire Routing ...............14
Outdoor Unitary Control.............................................19
Unit Operation ...........................................................20
Start-Up .....................................................................20
Homeowner Information ............................................22
Professional Maintenance .........................................23
Start-Up and Performance Checklist .........................25
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.damage, personal
injury, or death.
*P508296-01*
Issue 2231
WARNING
(P) 508296-01
Page 1 of 25
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Summary of Contents for Lennox 4SCU23LX
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Page 1: Table Of Contents
Manufactured By *P508296-01* Allied Air Enterprises LLC A Lennox International, Inc. Company 215 Metropolitan Drive (P) 508296-01 West Columbia, SC 29170 508296-01 Issue 2231 Page 1 of 25... -
Page 2: General
Install the unit high enough above the ground or roof to This unit must be installed with an approved indoor air allow adequate drainage of defrost water and prevent handler or coil. The 4SCU23LX variable capacity unit may ice buildup. be installed with an A3 communicating thermostat or a •... - Page 3 Elevate unit per local climate and code requirements to PLACEMENT provide clearance above estimated snowfall level and ensure adequate drainage of unit. Use snow stand in areas INSTALL UNIT AWAY FROM WINDOWS. where prolonged freezing temperatures are encountered. If conditions or local codes require the unit be attached to pad or mounting frame, tie down bolts should be used and fastened through knockouts provided in unit base pan.
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Page 4: Refrigerant Piping
36, and 48 com pressors. For installations of the important that the refrigerant system be kept closed 4SCU23LX unit with re frigerant lines or coils previously as much as possible. DO NOT remove line set caps charged with R410A and POE oil, Allied recommends... - Page 5 The 4SCU23LX is a variable-capacity cooling system utilizing variable speed compressor technology. With the IMPORTANT variable speed compressor and variable pumping capacity, additional consideration must be given to refrigerant piping The Clean Air Act of 1990 bans the intentional venting sizing and application.
- Page 6 Valve Size Connections Recommended Line Sets Tonnage * Liquid Line Suction Line Line Set Length 3/4” (19mm) 30’ (9.1m) 40’ (12.2m) 3/8” (10mm) 7/8” (22mm) 50’ (15.2m) 1-1/8” (29mm) ** Field-fabricated * Applicable to all minor revision numbers unless otherwise specified. ** Some applications may require a field-provided 1-1/8”...
- Page 7 Typical Existing Fixed Orifice Removal 1. On fully cased coils, remove the coil access and plumbing panels. Procedure Remove any shipping clamps from the liquid line and DISTRIBUTOR TUBES distributor assembly. LIQUID LINE ORIFICE HOUSING Disconnect the equalizer line from the fitting on the vapor line.
- Page 8 Flushing Line Sets If the unit will be installed in an existing system that uses WARNING an indoor unit or line sets charged with R-22 refrigerant, installer must perform the following flushing procedure. Refrigerant must be reclaimed in accordance with national and local codes.
- Page 9 Refrigerant Piping - Install Indoor Expansion Valve This outdoor unit is designed for use in systems that include an expansion valve metering device at the indoor coil. See the Product Specifications for approved expansion valve kit match-ups and application information. The expansion valve unit can be installed internal or external to the indoor coil.
- Page 10 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 11 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 12 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 13 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...
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Page 14: Electrical - Circuit Sizing And Wire Routing
Unit may have advantage of the advanced diagnostics and control, Wi- multiple power supplies. Fi accessibility and system operation parameters. Refer to the 4SCU23LX field wiring diagram for a Comfort Sync A3 communicating thermostat. WARNING Conventional 24VAC Non-Communicating Thermostat... - Page 15 (Jumper Y1 to Y2) Thermostat (non- communicating) Control Using Suction Pressure communicating) Table 6. 4SCU23LX Thermostat Control Options Size Circuit and Install Service Disconnect Install Thermostat Switch Install room thermostat (ordered separately) on an inside wall approximately in the center of the conditioned area Refer to the unit nameplate for minimum circuit ampacity, and 5 feet (1.5m) from the floor.
- Page 16 Connect the 208/230 high voltage power supply from the installed grommet installed in electrical inlet. disconnect to the 4SCU23LX contactor as shown. Connect the ground wire from the power supply to the unit ground Conventional 24VAC Non-Communicating Thermostat lug connection.
- Page 17 PROVIDED RAST 6-PIN CONNECTOR INDOOR CONTROL Indoor Control Single Wire To C Terminal Single Wire To C Terminal Unused Wires Unused Wires Figure 10. 4SCU23LX with Comfort Sync A3 Communicating Thermostat – Field Wiring 508296-01 Issue 2231 Page 17 of 25...
- Page 18 O.D. SENSOR O.D. SENSOR OPTIONAL OPTIONAL ACC2 ACC2 ACC1 ACC1 RAST 6-PIN RAST 6-PIN CONNECTOR CONNECTOR RAST 6-PIN RAST 6-PIN CONNECTOR CONNECTOR VARIABLE CAPACITY TWO STAGE / CONVENTIONAL 24VAC VARIABLE CAPACITY TWO STAGE / CONVENTIONAL 24VAC OUTDOOR UNIT VARIABLE SPEED NON-COMMUNICATING OUTDOOR UNIT VARIABLE SPEED...
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Page 19: Outdoor Unitary Control
Alarm information is provided on the unit control panel be installed on the Charge Mode Pins after providing a Y1 cover. cooling demand to the 4SCU23LX to initiate the Charge Mode. A cooling blower demand must also be provided to Charge Mode Jumper... -
Page 20: Unit Operation
If the cooling demand remains after 20 on Pins 2 & 3) and Comfort Mode (Jumper Removed). minutes, the 4SCU23LX control will begin to ramp up the The factory default position is the Efficiency Mode. The compressor capacity until maximum capacity is achieved. - Page 21 Part Recommended Torque OPERATING ANGLE-TYPE SERVICE VALVE Service valve cap 8 ft. lb. 11 NM 1 - Remove stem cap with an appropriately sized wrench. Sheet metal screws 16 in. lb. 2 NM 2 - Use a service wrench with a hex-head extension (3/16" for liquid Machine screws #10 28 in.
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Page 22: Homeowner Information
Checking Refrigerant Charge Homeowner Maintenance The 4SCU23LX unit is factory-charged with enough HFC- The following maintenance may be performed by the 410A refrigerant to accommodate a 15-foot length of homeowner. refrigerant piping. For refrigerant piping greater than 15 • Contact a licensed professional HVAC technician to feet, calculate the additional charge using Table 9. -
Page 23: Professional Maintenance
Pre-Service Check Check the cleanliness of outdoor fan and blade condition (cracks) and clean or replace them, if If your system fails to operate, check the following before necessary. calling for service: Inspect base pan drains for debris and clean as •... - Page 24 RT13 RT36 AMBIENT LIQUID COMPRESSOR SENSOR SENSOR S87 LOW S173 S4 HIGH COMPRESSOR PRESSURE RESISTOR PRESSURE SWITCH TOP CAP SWITCH (10K) SWITCH INVERTER GROUND NOTE- FOR USE WITH COPPER CONDUCTORS ONLY. REFER TO UNIT RATING PLATE FOR MINIMUM CIRCUIT AMPACITY AND MAXIMUM OVERCURRENT PROTECTION SIZE REFER TO COMPRESSOR IN UNIT FOR ACTUAL TERMINAL ARRANGEMENT...
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Page 25: Start-Up And Performance Checklist
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: _________...