Lennox Elite Series EL18KCV Air Conditioner Installation Instructions

General Information and Safety

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.

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.

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 29 in this instruction for information.

Unit Description

The EL18KCV outdoor air conditioner features an all-aluminum coil and is designed for use with R454B refrigerant only. It must be installed with an approved indoor air handler or coil. For AHRI Certified system match-ups and expanded ratings, visit www.LennoxPros.com.

The EL18KCV variable capacity unit can be installed with an S40 communicating thermostat or a standard 24VAC non-communicating cooling thermostat. Refer to field wiring diagrams for details.

These instructions are a general guide and do not supersede local codes. Consult authorities having jurisdiction before installation.

NOTICE: Charging information is provided 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 contact Technical Support at 800-453-6669.

NOTE: This unit EL18KCV is a PARTIAL UNIT AIR CONDITIONER, complying with PARTIAL UNIT requirements of UL 60335-2-40/CSA C22.2 No. 60335-2-40, or UL 1995/CSA C22.2 No 236. It must only be connected to other units confirmed as complying with corresponding PARTIAL UNIT requirements.

Unit Placement and Clearances

Proper placement and clearances are critical for safe and efficient operation.

Clearances

• Service clearance of 30 inches (762 mm) must be maintained on one side adjacent to the control box.
• Clearance to one of the other three sides must be 36 inches (914 mm).
• Clearance to one of the remaining two sides may be 12 inches (305 mm).
• The final side may be 6 inches (152 mm).
• A clearance of 24 inches (610 mm) must be maintained between two units.
• 48 inches (1219 mm) clearance is required on top of the unit.

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.

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 the roof surface.

Unit Dimensions:

Unit Placement Considerations:

• Install unit level or maintain a slope tolerance of 2 degrees (or 2 inches per 5 feet [50 mm per 1.5 m]) away from the building structure.
• Install units away from windows.
• Two 90° elbows installed in the line set will reduce line set vibration.

IMPORTANT: Exhaust vents from dryers, water heaters, and furnaces should be directed away from the outdoor unit. Prolonged exposure to exhaust gases and their chemicals may cause condensation and degrade unit components.

Refrigerant Piping

IMPORTANT: This model is designed for use in check/expansion valve systems only. An indoor expansion valve approved for R454B refrigerant must be ordered separately and installed prior to operation.

NOTE: An optional Unit Stand-Off Kit (94J45) is available. This kit provides black high-density polyethylene feet to raise the unit off the mounting surface.

The maximum altitude of use is 10,000 ft (3048 m).

Line Set Sizing

When installing a new line set, size the piping according to Table 1.

NOTE: Some applications may require a field-provided 7/8" to 1-1/8" adapter.

L15 Line Sets:

• L15-41 15 ft. - 50 ft. (4.6 m - 15 m)
• L15-65 15 ft. - 50 ft. (4.6 m - 15 m)

Field Fabricated:

• For -024 models: 3/8" Liquid, 3/4" Vapor
• For -036/-048 models: 3/8" Liquid, 7/8" Vapor
• For -060 models: 3/8" Liquid, 1-1/8" Vapor

Line Set Joints and Safety

Evaporator primary line set joints in all applications shall have a line set joint sleeve. Additional joints not covered by sleeves require compliance with specific options:

• Option 1: Furnace installed as a direct vent appliance.
• Option 2: Furnace/Evaporator installation in a space greater than the minimum conditioned area (Amin).
• Option 3: Connection to a space greater than Amin via an opening of at least 15 in. (4-inch diameter hole equivalent) below the furnace burners.
• Option 4: A second refrigerant detection sensor installed below the level of the burners.

For A2L refrigerant systems with additional joints, each system in the same space must have a refrigerant detection sensor below the burners, unless all systems are direct vent.

Secondary Sensor Installation:

• Upflow: Mounted on an unused side furnace return air connection, at least 9 inches above the floor and within 9 inches from the front of the furnace.
• Downflow: Mounted on one side of the evaporator coil, 9 inches above the floor and within 9 inches from the front of the coil.
• Horizontal: Mounted on the bottom side return furnace air connection within 9 inches of both the blower deck and front of the furnace.

Connect the sensor to the second sensor input on the RDS Control. Refer to sensor/controller instructions.

NOTE: For line sets longer than 50 feet, refer to the Refrigerant Piping Design and Fabrication Guidelines manual or contact Technical Support.

WARNING: Never use oxygen to pressurize or purge refrigeration lines. Oxygen can cause fire and/or explosion.

WARNING: Polyvinyl ether (PVE) oils used with R454B absorb moisture quickly. Keep the refrigerant system closed. Do not remove line set caps or service valve stub caps until ready to make connections.

IMPORTANT: Braze-free fittings must conform with UL207 or ISO14903.

Variable-Capacity System Considerations

The EL18KCV is a variable-capacity system. Special consideration is needed for refrigerant piping sizing.

• Total equivalent length: 180 feet (piping and fittings).
• Maximum linear (actual) length: 150 feet.
• Maximum linear liquid lift: 60 feet.
• Maximum length vapor riser: 60 feet.
• Up to 50 Linear Feet: Use rated line sizes in Table 1.
• Between 51 and 150 Linear Feet: Crankcase heater and non-bleed port TXV are factory installed. Vertical vapor riser must be sized per Table 2.
• Over 150 Linear Feet: Not recommended.
• Additional oil is not required for line lengths up to 150 feet.

Suction Traps: For systems where the outdoor unit is 5-60 feet above the indoor unit, install one trap at the bottom of the suction riser.

Adding Refrigerant for Long Line Sets

The charging method for long line sets involves adjusting the factory charge based on line set length and liquid line diameter.

Charging Formula for Liquid Line Charge Adjustments:

Total charge = Factory charge + Adjustment for line set length and liquid line diameter.

Example: Factory charge for 3/8" is 0.60 oz/ft x 15 ft = 9.0 ounces.

NOTE: Insulate the liquid line if routed through areas where ambient temperature could exceed liquid line temperature, or when pressure drop is 20 psig or greater.

* Applicable to all minor revision numbers unless otherwise specified.

** Some applications may require a field-provided 1-1/8" to 7/8" adapter.

NOTE: For new or replacement line set installation, refer to Service and Application Note - Corp. 9112-L4 (C-91-4).

Line Set Installation and Isolation

Line Set Isolation: Refrigerant lines must not contact structure. Use appropriate methods to isolate lines:

• Transition from Vertical to Horizontal: Use anchored heavy nylon wire tie or automotive muffler-type hanger.
• Installing Vertical Runs: Strap liquid line to suction line. Use non-corrosive metal sleeve. Use wood block between studs.
• Installing Horizontal Runs: Hang line set from joist or rafter using metal strapping material or anchored heavy nylon wire ties. Strap the suction line to the joist or rafter at 8-foot intervals, then strap the liquid line to the suction line. Use non-corrosive metal sleeve.

NOTE: Insulate liquid line when routed through areas where ambient temperature could exceed liquid line temperature or when pressure drop is 20 psig or greater.

IMPORTANT: Refrigerant lines must not contact wall.

NOTE: Similar installation practices should be used if the line set is installed on the exterior of an outside wall.

Expansion Valve Installation

This unit requires an expansion valve metering device (purchased separately) installed at the indoor coil. Refer to the EL18KCV Product Specifications bulletin (EHB) for approved kits.

Typical Existing Expansion Valve Removal Procedure (Uncased Coil Shown):

1. Remove coil access and plumbing panels.
2. Remove shipping clamps from liquid line and distributor assembly.
3. Disconnect equalizer line from the check expansion valve.
4. Remove the vapor line sensing bulb.
5. Disconnect the liquid line from the check expansion valve.
6. Disconnect the check expansion valve from the liquid line orifice housing.
7. Remove and discard the check expansion valve and Teflon® rings.
8. Use a field-provided fitting to temporarily reconnect the liquid line to the indoor unit's liquid line orifice housing.

Flushing Line Set Procedure:

1. Connect gauges and equipment for flushing. Use clean HCFC-22 for flushing.
2. Position cylinder to deliver liquid refrigerant.
3. Set recovery machine for liquid recovery, pull a vacuum on the line set and indoor coil.
4. Allow liquid refrigerant to flow through the system and into the recovery machine.
5. Switch recovery machine to vapor recovery to recover all HCFC-22 vapor.
6. Allow recovery machine to pull the system down to 0.
7. Close cylinder and gauge set valves. Pump remaining refrigerant out.

Indoor Expansion Valve Installation:

1. Install one Teflon® ring around the stubbed end of the check expansion valve. Lubricate connector threads and Teflon® ring surface with refrigerant oil.
2. Attach the stubbed end of the check expansion valve to the liquid line orifice housing. Finger tighten, then turn an additional 1/2 turn clockwise or tighten to 20 ft-lb.
3. Place the remaining Teflon® washer around the other end of the check expansion valve. Lubricate connector threads and Teflon® ring surface with refrigerant oil.
4. Attach the liquid line assembly to the check expansion valve. Finger tighten, then turn an additional 1/2 turn clockwise or tighten to 20 ft-lb.

Sensing Bulb Installation:

• Mount the vapor line sensing bulb in the proper orientation using the provided clamp and screws.
• On lines smaller than 3/4", mount the sensing bulb at the 1 or 11 o'clock position.
• On 3/4" and larger lines, mount the sensing bulb at the 3 or 9 o'clock position.
• NEVER mount the sensing bulb on the bottom of the line.
• Sensing bulb insulation is required if mounted external to the coil casing.

Equalizer Line Installation:

1. Remove and discard the flare seal cap or flare nut with copper flare seal bonnet from the equalizer line port on the vapor line.
2. Connect the equalizer line from the check expansion valve to the equalizer vapor port on the vapor line. Finger tighten the flare nut plus 1/8 turn (7 ft-lbs).

NOTE: Confirm proper thermal contact between vapor line and check/expansion bulb before insulating the sensing bulb.

NOTE: While installation on a horizontal run is preferred, vertical installation is acceptable if necessary. See figure for proper bulb orientation on vertical runs.

Leak Test and Evacuation

Leak Test

1. Connect the high pressure hose of an R454B manifold gauge set to the vapor valve service port. Connect the R454B cylinder to the center port.
2. With both manifold valves closed, open the R454B cylinder valve (vapor only). Open the high pressure side of the manifold to allow R454B into the line set and indoor unit. Weigh in a trace amount (max 2 oz or 3 psi). Close cylinder and manifold valves. Disconnect R454B cylinder.
3. Connect a cylinder of nitrogen with a pressure regulating valve to the center port.
4. Adjust nitrogen pressure to 160 psig (1103 kPa). Open the high side manifold valve to pressurize the system.
5. After a few minutes, open a service valve port and verify refrigerant is measurable with a leak detector. Leak check the entire system to a sensitivity of 5 grams per year.
6. After leak testing, disconnect gauges.

Evacuation

1. Remove cores from service valves (if not already done).
2. Connect gauge set: Low side to vapor line service valve (with 1/4 SAE in-line tee), high side to liquid line service valve, micron gauge to the tee, and vacuum pump to the center port.
3. Evacuate the line set and indoor unit to an absolute pressure of 23,000 microns (29.01 inches of mercury).
4. Close manifold valves, close vacuum pump valve, turn off vacuum pump. Disconnect hose from vacuum pump.
5. Attach hose to a nitrogen cylinder (160 psig) and purge the hose. Open manifold valves to break the vacuum. Close manifold valves.
6. Shut off nitrogen cylinder, remove hose. Open manifold valves to release nitrogen.
7. Reconnect manifold to vacuum pump. Evacuate until absolute pressure does not rise above 500 microns within a 20-minute period after pump shutdown and valve closure.
8. Disconnect hose from vacuum pump. Connect to R454B cylinder (liquid). Open manifold valve 1 to 2 psig to release vacuum.
9. Close manifold valves, shut off R454B cylinder. Reinstall service valve cores. Replace stem caps and tighten.

WARNING: Possible equipment damage. Avoid deep vacuum operation. Do not use compressors to evacuate a system. Extremely low vacuum can cause internal arcing and compressor failure. Damage caused by deep vacuum operation will void warranty.

Electrical Connections

Wiring must conform to current local codes and the National Electric Code (NEC) in the U.S.A., or the Canadian Electrical Code (CEC) in Canada.

Refer to furnace or air handler instructions for wiring diagrams and unit nameplate for ampacity and protection size.

• 24VAC Transformer: Use the transformer provided with the furnace or air handler (24VAC, 40 VA minimum).
• Refrigerant Detection System: Unit must be installed with a Lennox Approved Refrigerant Detection System (RDS) and sensor. Do not operate until the RDS is verified to be in good working order.

Thermostat Control Options

The EL18KCV offers two control options:

1. S40 Communicating Thermostat Control: Connect with 4 wires (R, I+, I-, C) for fully communicating operation, diagnostics, and Wi-Fi accessibility. Refer to the EL18KCV field wiring diagram for S40.
2. Conventional 24VAC Non-Communicating Thermostat Control:
   • Two-Stage Cooling: Requires 6 wires (R, C, W1, O, Y1, Y2) for full variable capacity operation controlled by the unit's onboard control using suction pressure.
   • Single-Stage Cooling: Requires 5 wires (R, C, W1, O, Y1). Y1 must be jumpered to Y2 on the outdoor unit. Performance data is based on a two-stage thermostat.

IMPORTANT: The conventional 24VAC non-communicating thermostat must have a compressor minimum on-time of three minutes to prevent short cycling.

Installation Steps

1. Size Circuit and Install Service Disconnect Switch: Refer to unit nameplate for minimum circuit ampacity and maximum fuse/breaker size. Install power wiring and disconnect switch.
2. Install Thermostat: Place thermostat on an inside wall, centered in the conditioned area, approximately 5 feet (1.5m) from the floor. Avoid outside walls or areas affected by sunlight or drafts.
3. Route Control Wires:
   • Communicating Thermostat Wiring: Maximum length (18 gauge) for RSBus is 1500 feet (457 meters). Use color-coded, solid-core Class II rated wiring (95°F/35°C minimum temperature rating). Route through a field-provided grommet.
   • Conventional 24VAC Wiring: Use 18 AWG wire for runs less than 100 ft, and 16 AWG for runs over 100 ft. Ensure insulation has a 35°C minimum temperature rating.
4. Route High Voltage and Ground Wires: Secure excess high voltage wiring away from low voltage wiring. Use watertight conduit for high voltage connections. Connect power supply to the EL18KCV contactor and ground wire to the unit ground lug.

WARNING: Electric Shock Hazard. Unit must be properly grounded. Use copper wire only.

WARNING: Failure to use properly sized wiring and circuit breaker may result in property damage.

IMPORTANT: 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.

IMPORTANT: Electrostatic discharge can affect electronic components. Touch unpainted unit surface and tools on an unpainted unit surface before service to neutralize electrostatic charge.

Outdoor Unitary Control Jumpers and Terminals

The outdoor control features a 7-segment display and push button for operation information and alarms.

Charge Mode Jumper

Install the jumper across the CHRG MODE pins to initiate Charge Mode. This mode runs the compressor and outdoor fan at 100% capacity for charging, checking charge, pumping down, and other service procedures.

• With S40 Thermostat: Installing the jumper initiates 100% compressor/fan operation and signals the indoor unit for maximum cooling air volume. Remove the jumper to exit. Max time: 60 minutes.
• With Conventional Thermostat: The jumper must be installed after providing a Y1 cooling demand (and 'O' signal for cooling). A cooling blower demand is also required. Remove jumper and demands to exit. Max time: 60 minutes.

Operation Mode Jumper (Conventional Thermostats Only)

This jumper controls compressor capacity by maintaining target suction pressure setpoints.

• Efficiency Mode (Factory Default): Jumper on Pins 1 & 2. Variable suction pressure setpoint varies with outdoor temperature (lower setpoint at higher outdoor temps).
• Normal Mode: Jumper on Pins 2 & 3. Suction pressure setpoint is 135 psig.
• Comfort Mode: Jumper Removed. Suction pressure setpoint is 125 psig.

Unit Operation

• With S40 Communicating Thermostat: Unit capacity is controlled variably from minimum to maximum based on thermostat demand. Indoor airflow is matched to cooling capacity.
• With Conventional 24VAC 2-Stage Thermostat: Y1 demand initiates first stage operation. Compressor capacity varies to meet target suction pressure. Y2 demand initiates second stage blower operation. Compressor capacity ramps up to maximum if Y2 demand persists for 20 minutes.
• With Conventional 24VAC Single-Stage Thermostat: Y1 demand initiates operation. Y1 must be jumpered to Y2. Compressor capacity varies to meet target suction pressure. Capacity ramps up to maximum if demand persists for 20 minutes.

Unit Start-Up

1. If equipped with a crankcase heater, energize it 24 hours before start-up.
2. Rotate fan to check for binding.
3. Inspect all wiring for loose connections.
4. After evacuation, open liquid and vapor line service valve stems.
5. Replace stem caps and tighten per Table 5.
6. Check voltage supply at disconnect switch; ensure it's within nameplate range.
7. Connect manifold gauge set for testing and charging.
8. Set thermostat for cooling demand. Turn on power to indoor unit and close outdoor unit disconnect switch.
9. Recheck voltage while unit is running.
10. Check system for sufficient refrigerant using procedures under "Checking Refrigerant Charge".

Operating Service Valves

Service valves are used for refrigerant removal, flushing, leak testing, evacuation, charge checking, and charging.

• Ball-Type Service Valve: Remove stem cap. Rotate stem counterclockwise 90° to open, clockwise 90° to close.
• Angle-Type Service Valve: Remove stem cap. Back out stem counterclockwise using a service wrench with a hex-head extension. When back-seated (open), the service port is open to the line set. When front-seated (closed), the service port is open to the line set and indoor unit.

Access Service Port: Remove service port cap. Connect gauge set. Replace cap and tighten (finger tight plus 1/6 turn or per torque spec). Replace stem cap and tighten (finger tight plus 1/12 turn or per torque spec).

IMPORTANT: To prevent stripping of caps, use the appropriately sized wrench and fit it snugly before tightening.

Manifold Gauge Set: Use low loss fittings. Gauges must be rated for R454B pressures (0-800 psig high side, 30" vacuum to 250 psig low side). Hoses must be rated for 800 psig with a 4000 psig burst rating.

Charging

Verify electrical grounding before charging. Do not overfill the system.

Charge should be checked and adjusted using information on the charging label and in this section.

R454B is a zeotropic blend and must be charged with liquid refrigerant.

The EL18KCV is factory-charged for a 15-foot line set. Add 3 oz of refrigerant for every 5 feet of piping beyond 15 feet.

Initiate cooling demand, allow pressures and temperatures to stabilize. Adjust charge using the subcooling method. Compare results with the unit charging label's target Subcooling Values.

Subcooling Calculation: Subcooling = Saturated Liquid Temperature - Liquid Line Temperature.

After charging, mark the additional charge and total charge on the unit nameplate.

NOTE: Insulate liquid line when routed through areas where ambient temperature could exceed liquid line temperature or when pressure drop is 20 psig or greater.

High Pressure Switch (S4): Opens when liquid line pressure exceeds 590 ± 15 psig; resets at 418 ± 15 psig.

*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.

Homeowner and Professional Maintenance

Homeowner Maintenance

• Contact a licensed professional HVAC technician for inspection and maintenance before each cooling and heating season.
• Check the indoor unit filter monthly and replace if necessary. Ask your Lennox dealer to show you the filter location.
• Check the indoor unit drain line for obstructions monthly.
• Check the area around the outdoor unit monthly and remove obstructions (grass clippings, leaves, etc.).
• Trim shrubbery away from the unit and check for debris.
• During winter, keep snow level below the louvered panels.

IMPORTANT: Sprinklers and soaker hoses should not cause prolonged exposure to the outdoor unit by treated water, as it will corrode parts and diminish performance.

Refer to the thermostat homeowner manual for operation instructions.

Pre-Service Check

• Verify thermostat settings.
• Verify electrical disconnect switches are ON.
• Check for 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 before calling.

Professional Maintenance

NOTICE! Failure to follow instructions will cause damage to the unit.

Aluminum Coil Cleaning: Aluminum coils may be damaged by solutions with pH below 5 or above 9. Clean using potable water (less than 50 psi). If water alone is insufficient, use a coil cleaner with a pH between 5 and 9. Rinse thoroughly. In coastal areas, clean with potable water several times per year.

The system should be inspected and maintained twice yearly by a licensed professional HVAC technician.

Outdoor Unit Checks:

• Inspect component wiring for loose, worn, or damaged connections. Check for rubbing or pinching. Confirm proper voltage and amperage.
• Check outdoor fan and blade condition; clean or replace if necessary.
• Inspect base pan drains for debris.
• Inspect refrigerant piping condition and insulation. Ensure pipes are not rubbing copper-to-copper.
• Test capacitor; replace if necessary.
• Inspect contactor contacts for pitting or burn marks; replace if necessary.
• Check outdoor fan motor for worn bearings/bushings; replace if necessary.
• Inspect and clean outdoor coils; note any damage or signs of leakage.

Indoor Unit Checks:

• Inspect component wiring for loose, worn, or damaged connections. Confirm proper voltage and amperage.
• Inspect and clean or replace air filters.
• Check blower cleanliness; clean if necessary.
• Inspect drain pans and condensate drains for rust, debris, obstructions, leaks, or cracks. Test drainage.
• Inspect and clean indoor coil.
• Inspect refrigerant lines condition and insulation. Ensure pipes are not rubbing copper-to-copper or affected by indoor air contamination.
• Inspect duct system for leaks or other problems.
• Check indoor blower motor for bearing/bushing wear.
• If matched with a gas/oil furnace, inspect burners, gas valve, heat exchanger, and flue system.

General System Test with System Operating

The technician will perform a general system test, checking startup/shutoff, noises, odors, temperatures, and pressures. They will verify refrigerant charge per the charging sticker.

Verify system total static pressure and airflow settings are within operating parameters.

Verify correct temperature drop across the indoor coil.

R-454B Refrigerant Pressure-Temperature Chart

This chart provides saturation temperatures for R-454B refrigerant at various pressures.

Notes:

1. R-454B is a zeotropic blend and must be charged with liquid refrigerant only.
2. Saturated liquid temperature is used to calculate liquid subcooling.
3. Saturated vapor temperature is used to calculate suction superheat.
4. See unit charging label for subcooling values and additional charging information.

EL18KCV Start-Up and Performance Checklist

Customer:

Indoor Unit Model:

Outdoor Unit Model:

Address:

Serial:

Notes:

START UP CHECKS

Refrigerant Type: R454B

Rated Load Amps:

Condenser Fan Full Load Amps:

Actual Amps:

Rated Volts:

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))