LG Room Air Conditioner SERVICE MANUAL website http://www.lgservice.com CAUTION • BEFORE SERVICING THE UNIT, READ THE SAFETY PRECAUTIONS IN THIS MANUAL. • ONLY FOR AUTHORIZED SERVICE PERSONNEL.
SERVICE MANUAL This parts etc. This room air conditioner was manufactured and assembled under a strict quality control system. The refrigerant is charged at the factory. Be sure to read the safety precautions prior to servicing the unit. 1.1 SAFETY PRECAUTIONS 1.
This feature extends the overall life of compressor by preventing the short-cycling of the air-conditioner. When the compressor restarts, LG PTAC is designed to give a minimum of three minutes to have a time of equalizing the refrigerant pressures for optimizing cycling.
Page 5
The unit will activate the reverse cycle defrost When the outdoor coil temperature has remained at a cold temperature to form the ice on the coil.This ice will reduce airflow though the coil and will also reduce the efficiency of unit. The LG PTHP will employ an active reverse cycle defrost function to melt the ice off the outdoor coil for insuring room comfort conditions and savings from extended operation.
The damper is opened and outdoor air is drawn into the room. This will reduce the cooling or heating efficiency. CAUTION When the air conditioner has performed a cooling or heating operation and is turned off or set to the fan position, wait at least 3 minutes before resetting to the cooling operation.
1.4 ADDITIONAL CONTROLS • REMOVING THE FRONT GRILLE Additional controls are available after removing the front grille and option cover of control box. To remove the front grille, pull out the bottom of front grille and then lift up. To replace the front grille, place the tabs over the top of the unit and push the bottom of front grille until the clips snap into place.
• REMOTE/LOCAL CONTROL When remote/local switch #1 is on, it allow the unit to operate by the control of Remote Wall Thermostat. The unit control by knobs are not available. • ENERGY SAVER The energy saver switch #2 is on. This switch is set at continuous fan to provide continuous fan operation in cool or heat modes.
• This Room Air Conditioner (PTAC) discharges air from the top of the unit through reversible, 2-position discharge grille louvers. The unit is shipped from the factory with the discharge grille louvers at an angle of 40˚...
2.1.2 CONTROL BOX (Half-Disassembly) 1. Remove the front grille. (Refer to section 2.1.1) 2. Remove the three screw which fasten the control box. (See Fig. 2) 3. Pull the control box from the barrier. (See Fig.2) 4. Discharge the capacitor by placing a 20,000 ohm resistor across the capacitor terminals.
2.2 AIR HANDLING PARTS 2.2.1 HEATER ASSEMBLY AND CROSS FLOW FAN 1. Remove the front grille. (Refer to section 2.1.1) 2. Remove the control box assembly. (Refer to section 2.1.3) 3. Remove the 3 screws which fasten the net steel. (See Fig.
2.2.3 SHROUD 1. Remove the fan. (Refer to section 2.2.2) 2. Remove the screw which fastens the shroud. 3. Remove the shroud. (See Fig. 8) 4. Re-install the component by referring to the removal procedure, above. 2.3 ELECTRICAL PARTS 2.3.1 OUTDOOR MOTOR 1.
2.3.5 POWER CORD 1. Remove the control box. (Refer to section 2.1.2) 2. Disconnect the grounding screw from the control box. 3. Disconnect 2 receptacles. 4. Remove a screw which fastens the clip cord. 5. Separate the power cord from the control box. (See Fig.
2.4 REFRIGERATION CYCLE CAUTION Discharge the refrigerant system using Freon Recovery System. If there is no valve to attach the recovery system, install one (such as a WATCO A-1) before venting the Freon . Leave the valve in place after servicing the system. 2.4.1 CONDENSER 1.
Page 15
NOTES — Replacement of the refrigeration cycle. 1. When replacing the refrigeration cycle, be sure to discharge the refrigerant system using a Freon recovery System. If there is no valve to attach the recovery system, install one (such as a WATCO A-1) before venting the Freon .
Page 16
Equipment needed: Vacuum pump, Charging cylinder, Manifold gauge, Brazing equipment. Pinch-off tool capable of making a vapor-proof seal, Leak detector, Tubing cutter, Hand Tools to remove components, Service valve. Figure 16A-Pulling Vacuum Figure 16B-Charging —16—...
You can install the new air conditioner according to these installation instructions to achieve the best performence. All wall sleeves used to mount the new air conditioner must be in good structural condition and have the rear grille that securely attaches to the sleeve or the flange of the sleeve to secure the new air conditioner.
3.2 SUGGESTED TOOL REQUIREMENTS SCREWDRIVER(+, -), RULER, KNIFE, HAMMER, PENCIL, LEVEL 3.2.1 PREPARATION OF SLEEVE SLEEVE HARDWARE NUMBER NAME OF PARTS SLEEVE LOWER SLEEVE UPPER SCREW OUTDOOR GRILLE DRAIN KIT ASSEMBLE THE WALL SLEEVE • Raise the sleeve side panels to upright position as shown on the right.
3.2.3 UNIT INSTALLATION 1. Remove the shipping screw from the ventilation door. (See Fig. 17) 2. Remove the front gille by pulling it out at the bottom to release it, then lift it up along the unit top front. (See Fig. 18) 3.
3.3.2 ELECTRICAL SAFETY IMPORTANT GROUNDING INSTRUCTIONS Air conditioner has a three-prong grounding plug on its power supply cord, which must be plugged into properly grounded three-prong wall receptacle for your protection against possible shock hazard. FUSE – Use a time-delay fuse or circuit breaker. Refer to the nameplate for proper power supply requirements.
4. PERFORMANCE DATA Air Conditioner Performance Data Voltage (V) Cooling Data Cooling Capacity (Btu/h) Cooling Amps (A) Cooling Power (W) EER (Btuh/Watt) Moisture Removal (Pts/h) Airflow Indoor CFM (Wet) @0.3ESP (Hi) Indoor CFM (Wet) @0.3ESP (Lo) Indoor CFM (Dry) @0.3ESP (Hi) Indoor CFM (Dry) @0.3ESP (Lo)
Page 22
Cooling Wattage - Air Conditioners Model Temperature Outdoor Return Air Dry Bulb Wet Bulb Rating Wattage LP120CEM Total Wattage Input 1045 1090 1050 1180 1055 1180 1060 1180 1055 1180 1050 1180 1045 1175 1030 1160 1000 1125 1005 1130 1005 1135 1005...
Page 23
Cooling Wattage - Heat Pumps Model LP090HM* Temperature Outdoor Return Air Total Wattage Dry Bulb Wet Bulb Input Rating Wattage LP120HEM Total Wattage Input 1120 1145 1120 1230 1125 1235 1130 1240 1125 1240 1120 1230 1115 1230 1100 1210 1070 1180 1075...
Page 24
Cooling change of temperature - Air Conditioners Room Air Room Air Temperature Across Bulb Bulb Rating Btu/h 11700 Rating CFM Cooling Change of Temperature - Heat Pumps Room Air Room Air LP090HEM Temperature Across Bulb Bulb Indoor Coil ( T) Rating Btu/h 9300 Rating CFM...
Page 25
Heating Change of Temperature - Heat Pumps Room Air Room Air LP090HEM Temperature Across Bulb Bulb Indoor Coil ( T) Rating Btu/h 8200 Rating CFM Cooling Ampere Chart - Air Conditioners Cond Inlet Air Model Temperature LP120CEM Amperage Min Max Rating Ampere Cooling Ampere Chart - Heat Pumps Cond Inlet Air...
Refer to Fig. 21 to follow the refrigeration cycle and the flow of the refrigerant in the cooling cycle. EVAPORATOR COILS COOLED LIQUID PRESSURE DROP 1,066mm(42") 505mm(20") ROOM AIR CONDITIONER CYCLE OF REFRIGERATION SUCTION LIME COMPLETE LIQUID COOL LOW PRESSURE VAPOR BOIL OFF POINT ROOM AIR HEAT LOAD OUTSIDE COOLING...
5.3 TROUBLESHOOTING GUIDE In general, possible trouble is classified in two causes. The one is called Starting Failure which is caused from an electrical defect, and the other is Ineffective Air Conditioning caused by a defect in the refrigeration circuit and improper application. Unit is running but cooling is ineffective Check of cold air circulation for smooth flow.
Page 28
Check of power source. Check of control switch setting. Only compressor fails to start. Drop of power voltage. Defect of compressor capacitor. Check capacitor. Replacement. Irregular motor resistance ( ) Irregular motor insulation ( ) Replacement of compressor (Motor damaged) Fails to Start Improper thermostat setting Loose terminal connection.
Page 29
COMPLAINT Fan motor will not run. No power Power supply cord Rotary switch Wire disconnected or connection loose Capacitor (Discharge capacitor before testing.) Will not rotate Fan motor runs Revolves on overload. intermittently Fan motor noise. Grommets Turbo fan Loose set screw Worn bearings CAUSE Check voltage at outlet.
Thermostat Capacitor (Discharge capacitor before servicing.) Compressor Overload ROOM AIR CONDITIONER VOLTAGE LIMITS NAME PLATE RATING 208/230V CAUSE Check voltage. See the limits on the preceding. page. If not within limits, call an electrician. Check the wire connections, if loose, repair or replace the terminal.
Page 31
COMPLAINT Compressor cycles Voltage on overload. Overload Fan motor Condenser air flow restriction Condenser fins (damaged) Capacitor Wiring Refrigerating system Insufficient cooling or Air filter heating Exhaust damper door Unit undersized Excessive noise. Cross flow fan Copper tubing CAUSE Check the voltage. See the limits on the preced- ing page.