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Page 21

NOTICE !

Failure to follow instructions will cause damage to 

the unit.
This unit is equipped with an aluminum coil. Alu-

minum coils may be damaged by exposure to solu-

tions with a pH below 5 or above 9. The aluminum 

coil should be cleaned using potable water at a mod-

erate 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 po-

table water several times per year to avoid corrosive 

buildup (salt).

Indoor Unit 

1. Clean or change filters. 

2. Lennox blower motors are prelubricated and perma

-

nently sealed. No more lubrication is needed. 
3. Adjust blower speed for cooling. Measure the pressure 

drop over the coil to determine the correct blower CFM. 

Refer to the unit information service manual for pressure 

drop tables and procedure. 

4.  Belt  Drive  Blowers  -  Check  belt  for  wear  and  proper 

tension. 
5. Check all wiring for loose connections. 
6. Check for correct voltage at unit. (blower operating) 
7. Check amp draw on blower motor. 

Motor Nameplate:_________ Actual:__________. 

Indoor Coil 

1 - 

Clean coil if necessary. 

2 - 

 Check connecting lines, joints and coil for evidence 

of oil leaks. 

3 - 

Check condensate line and clean if necessary. 

HOMEOWNER

 

Cleaning of the outdoor unit's coil should be performed by 

a trained service technician. Contact your dealer and set 

up a schedule (preferably twice a year, but at least once a 

year) to inspect and service your outdoor unit. The follow

-

ing maintenance may be performed by the homeowner.

 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. 

Outdoor Coil 

The outdoor unit must be properly maintained to ensure 

its proper operation. 
•   Please contact your dealer to schedule proper inspec

-

tion and maintenance for your equipment. 

• 

 Make sure no obstructions restrict airflow to the outdoor 

unit. 

•   Grass clippings, leaves, or shrubs crowding the unit can 

cause the unit to work harder and use more energy. 

•   Keep shrubbery trimmed away from the unit and peri

-

odically check for debris which collects around the unit. 

Routine Maintenance 

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. 

1 - 

 

Air Filter

 – Ask your Lennox dealer to show you 

where  your  indoor  unit's  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. 

2 - 

 

Disposable Filter

  –  Disposable  filters  should  be 

replaced with a filter of the same type and size. 

NOTE

 – 

If you are unsure about the filter required for your 

system, call your Lennox dealer for assistance.

 

3 - 

 

Reusable Filter

 – Many indoor units are equipped 

with  reusable  foam  filters.  Clean  foam  filters  with 

a mild soap and water solution; rinse thoroughly; 

allow  filter to dry completely  before  returning  it to 

the unit or grille. 

NOTE

 – 

The filter and all access panels must be in place 

any time the unit is in operation.

 

4 - 

 

Electronic Air Cleaner

 – Some systems are 

equipped with an electronic air cleaner, designed 

to remove airborne particles from the air passing 

through the cleaner. If your system is so equipped, 

ask your dealer for maintenance instructions. 

5 - 

 

Indoor Unit

 – The indoor unit's evaporator 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.) 

Thermostat Operation 

See the thermostat homeowner manual for instructions on 

how to operate your thermostat.

Preservice 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. 

Summary of Contents for ML18XC2 Series

Page 1: ...cal Unit Parts Arrangement 5 Operating Gauge Set and Service Valves 5 Unit Placement 7 Removing and Installing Louvered Panels 8 New or Replacement Line Set 9 Brazing Connections 11 Flushing Line Set...

Page 2: ...the remaining two sides may be A clearance of 24 in must be maintained between two units 48 in 1219 mm clearance required on top of unit Model Number Identification Nominal Cooling Capacity 024 2 ton...

Page 3: ...NNECTION 6 3 8 162 TOP VIEW BASE SECTION COMPRESSOR COIL DRAIN OUTLETS Around perimeter of base OPTIONAL UNIT STAND OFF KIT 4 Field Installed 111 4 3 8 4 3 8 4 3 8 4 3 8 6 3 8 162 111 111 111 111 4 3...

Page 4: ...t ampacity MCA 14 6 20 2 26 2 32 2 Compressor Rated load amps 10 9 15 4 19 9 23 7 Locked rotor amps 61 92 127 151 Power factor 0 97 0 94 0 93 0 92 Outdoor Fan Motor Full load amps 1 1 1 4 2 6 Locked R...

Page 5: ...ugly over the cap before tightening TABLE 1 Torque Requirements Parts Recommended Torque Service valve cap 8 ft lb 11 NM Sheet metal screws 16 ft lb 2 NM Machine screws 10 28 ft lb 3 NM Compressor bol...

Page 6: ...7 8 9 10 11 12 1 12 TURN To 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...

Page 7: ...ent of unit in relation to a window see the provided illustration in figure 3 detail A PLACING UNIT ON SLAB When installing unit at grade level the top of the slab should be high enough above grade so...

Page 8: ...ons that may cause panels to be blown around and battered WARNING REMOVAL STEP 1 INSERT PANEL UNDER UNIT TOP CAP LIP AND LIFT SLIGHTLY TO CLEAR SIDE LIP OF PANEL FROM BASE STEP 2 PANEL INSTALLATION TO...

Page 9: ...ge in the system No need to add oil in system with 20 pounds of refrigerant or less For systems over 20 pounds add one ounce for every five pounds of refrigerant Recommended topping off POE oils are M...

Page 10: ...be used if line set is to be installed on exterior of outside wall PVC PIPE FIBERGLASS INSULATION CAULK OUTSIDE WALL VAPOR LINE WRAPPED WITH ARMAFLEX LIQUID LINE OUTSIDE WALL LIQUID LINE VAPOR LINE WO...

Page 11: ...dous 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...

Page 12: ...SERVICE VALVE 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 suction vapor line service port valve CUT AND D...

Page 13: ...tions for the next step in preparing the unit WHEN BRAZING LINE SET TO SERVICE VALVES POINT FLAME AWAY FROM SERVICE VALVE PREPARATION FOR NEXT STEP 7 WARNING 1 FIRE PERSONAL INJURY OR PROPERTY DAMAGE...

Page 14: ...ISTING INDOOR UNIT GAUGE MANIFOLD INVERTED CYLINDER CONTAINS CLEAN HCFC22 TO BE USED FOR FLUSHING LIQUID LINE SERVICE VALVE INLET DISCHARGE TANK RETURN CLOSED OPENED RECOVERY CYLINDER RECOVERY MACHINE...

Page 15: ...reads and expose surface of the Teflon ring with refrigerantoil E Attach the liquid line assembly to the expansion valve Finger tighten and use an appropriately sized wrench to turn an additional 1 2...

Page 16: ...losed 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 allo...

Page 17: ...r 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...

Page 18: ...to unit nameplate for minimum circuit ampacity and maximum overcurrent protection size 24VAC TRANSFORMER Use the transformer provided with the furnace or air han dler for low voltage control power 24...

Page 19: ...Y1 Y2 C K1 S4 R C R W2 W1 Y2 C BLACK BLUE YELLOW Y Y1 G G W INDOOR UNIT TB1 THERMOSTAT A2 EL196E ML180E ML193E EL180E EL195E ML196E R W2 W1 G C BLACK BLUE YELLOW Y1 Y2 INDOOR UNIT A92 TB1 DS O W914 W9...

Page 20: ...to shut off compressor operation The auto reset switch closes when the compressor cas ing temperature falls to 151 187 F 66 C 86 C and the compressor is re energized This single pole single throw SPS...

Page 21: ...sure no obstructions restrict airflow to the outdoor unit Grass clippings leaves or shrubs crowding the unit can cause the unit to work harder and use more energy Keep shrubbery trimmed away from the...

Page 22: ...all factory and field installed wiring for loose connections 3 After evacuation is complete open the liquid line and suction line service valves to release the refrigerant charge contained in outdoor...

Page 23: ...pply 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...

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