air conditioner maintenance and inspection specification service department of import and export...

Air Conditioner Maintenance and Inspection Specification

Service Department of Import and Export Corporation

September 2010

部门2 日期

This specification is the basic operating process specification that shall be followed in maintenance and inspection of air conditioner. This specification is formulated to ensure standard operation in inspection and maintenance of air conditioner, personal safety and good properties of air conditioner.

This specification is mainly suitable for air conditioner for export loader of our company. In use and maintenance of air conditioner, please read this specification carefully.

部门3 日期

Contents1. Brief Introduction to Air Conditioner

1.1 System Assembly

1.2 Technical Parameters

1.3 Working Principle

1.3.1 Refrigerating Working Principle

1.3.2 Heating Working Principle

1.4 Operation Method

2. Maintenance of Air Conditioner

2.1 Routine Maintenance of Air Conditioner

2.2 Maintenance and Cycle of Air Conditioning System

3. Common Troubleshooting

3.1 Maintenance Notice

3.2 Poor Refrigerating Effect

3.3 No Refrigeration

3.4 High Noise

4. Coolant Filling

4.1 Creation of Vacuum

4.2 Leakage Detecting

4.3 Coolant Filling

5. Security Matters

部门4 日期

1. Brief Introduction to Air Conditioner

部门5 日期

1. Brief Introduction to Air Conditioning System

SDLG Air Conditioning System consists of compressor, evaporator assembly, condenser assembly, liquid storage tank, throttled components, refrigeration hoses, etc. Compressor is driven by vehicle engine through belt. Power supply is provided by vehicle power supply. Panel switch controls temperature and air volume. It has large air volume and fast refrigeration. With high-quality components, the system has stable and reliable performance and good vibration resistance. It can provide a comfortable working environment for operator. Compressor

Evaporator Assembly

Liquid Storage Tank

Condenser Assembly

Refrigeration Hose

1.1 Composition of System

部门6 日期


1.2 Technical Parameters

Refrigerating output

4600W Air volume 480 /h

Voltage 24 or 12V Total power consumption

≤310W

Compressor 508 or 5H14 Coolant R12 or R134a

Filling amount of coolant

1000-1300g Heating capacity

5000W

3m

部门7 日期


1.3 Working Principle

1.3.1 Refrigerating Working Principle

Cold Air

Hot Air

Front Cooling Air

Air in Vehicle

Expansion Valve

Hydraulic CoolantBlower MotorLow-pressure and

Low-temperature Gas

Thermal Cylinder

Evaporator

Service Valve at Low-pressure Side

Service Valve at High-pressure Side

Low-pressure and Low-temperature Liquid

Low-pressure and Low-temperature Mist Coolant

High-pressure and High-temperature Gas

Compressor Condenser

Middle-temperature and High-pressure and Liquid

Cooling Fan of Engine

Liquid Storage Tube

Desiccant (with sack)Filter Screen

Liquid Storage Tank

Composition and Working Principle of Air Conditioning System

部门8 日期

A Compression process Low-temperature and low-pressure

coolant is absorbed by compressor , compressed into high-temperature and high-pressure coolant gas and delivered to condenser. This process consumes mechanical work.

B Condensation process

High-temperature and high-pressure refrigeration gas is delivered to condenser for compelling cooling. It gradually becomes high-temperature

and high-pressure liquid coolant.

C Throttling expansion process

After dried and filtered by fluid rervoir, liquid coolant is delivered to expansion valve. It becomes low-temperature and low-pressure liquid after throttling expansion of expansion valve. In this process, pressure and temperature decline sharply.

D Evaporation

process Coolant enters evaporator after

cooling by expansion valve. Liquid absorbs heat after vaporization and changes into low-temperature and low-pressure gas, which is delivered to compressor. Air in the vehicle is blown by fan to evaporator for heat absorption, in order to achieve the purpose of

refrigeration.

Cold air

Cold air

cold air in vehicle

Ahead cooling wind

sirocco

部门9 日期


1.3.2 Heating Working Principle

Heating uses cooling water of engine.

A. Pressure control

Pressure of the system is controlled by high/low pressure switch. Pressure ranges from 0.169 MPa to 3.14 MPa. The system pressure will disconnect when there is less or no medium. When system pressure is abnormally high, compressor will also be disconnected to protect the system.

B. Power fuse

The system is equipped with three-route fuse to prevent short circuit and overload.

C.Fusible plug （ high-temperature ） control

When system pressure is beyond 2.9MP or system medium is up to 102-110 , fusible plug will melt. Medium in the system will be ℃discharge to air to prevent the whole system from being damaged.

部门10 日期

Electrical Principle Drawing of Air Conditioner

Fuse

Relay

Pressure Switch

Compressor

Condensate Fan

Note: Dotted line represents wiring of host machine.

Temperature Controller

Indicating Light

Temperature Sensitive Probe

Rheostat Evaporator Fan

3-gear Switch

部门11 日期


1.4 Operation Method

Air Volume and Power Switch

Indicating Light

Temperature Control Switch

部门12 日期


A. Refrigeration

◆ Start engine

◆ Turn on air volume and air power switch. Adjust air volume to maximum

◆ Turn on temperature controlled switcha and adjust to minimum （ Indicating light is on ）

◆ Air conditioner begins refrigeration. After temperature is appropriate, adjust temperature controlled switch until indicating light is off.

◆ Adjust air volume switch （ 3 gears. After temperature is appropriate, adjust air volume to middle or small gear ）

◆ Adjust tuyere direction

B. Heating

◆ Start engine

◆ Open waterway valve

◆ Turn on power switch

◆ Adjust air volume switch

Warning ：

Heater valve should be closed during refrigeration in summer.

Refrigeration temperature controlled switch should be turned off during refrigeration in winter.

部门13 日期


部门14 日期


Service life of air conditioner on loader depends largely on user's normal maintenance.

2.1 Routine Maintenance of Air Conditioner

a) Check and clean condenser of air conditioner. Cooling fins are required to be clean. There is no blocking in fins. They shall be cleaned with cold water or compressed air, but not hot water or hot air.

b) Check amount of coolant in refrigeration system. Observe through observation window of liquid reservoir. Under normal circumstances, there is no bubble in the observation window. When rotate speed of engine changes, there are a small number of bubbles.

c) Check tensioning degree of compressor transmission belt.

d) Check whether appearance of tubes are normal and whether joint are firm.

e) Check whether power line of refrigerating system is firm and whether there is open circuit or short circuit.

Caution ：

No matter whether air conditioner is used, pipelines and other devices shall be inspected and maintained regularly.

If air conditioner is used for several months, it shall be opened once a month for 10 minutes each time for normal operation of system.

In winter antifreeze solution must be added for fan heater system to prevent core from frost crack.

部门15 日期


2.2 Maintenance and Cycle of Air Conditioning SystemMaintenance and Cycle of Air Conditioning System

No. Item ContentMaintenance Cycle

W M S Y

1 Evaporator

Whether there is abnormal noise during operation of motor★

　★

　　　

Whether inlet and outlet of air is smooth 　 ★　　　

Whether draining is smooth 　 ★　　　

2 Compressor

Whether fixed bolts are loosen 　 ★　　　

Whether tightness of belt is appropriate 　　 ★ 　

Whether clutch normally sucks 　　 ★　　

Adding of refrigeration oil 　　 ★　　

3 Condenser Whether core is clean. Regular cleaning 　 ★　　　

4 CoolantObserve through window of reservoir. Normally without

bubbles. Otherwise, there is leakage　 ★

　　　

5 Pipelines

Whether joints loosen or leak (There are generally oil strains of leakage)

　 ★　　　

Whether pipelines are damaged 　 ★　　　

6 3-gear switch Whether gear is clear. Whether air volume changes clearly★

　　　　

7Electric

connections

Whether connections loosen, fall off or get exposed 　　 ★　　

8Temperature

controllerWhether it works normally. Whether indicating light is

normally on★

　　　　

9 SystemWhether all components operate normaly adn there is no

abnormal noise.　 ★

　　　

部门16 日期

3. Common Troubleshooting

部门17 日期

1 The operator shall receive vehicle air conditioning basic knowledge and safety knowledge training.

2 Work environment shall be clean and moisture-proof. Sewage water entering circuit must be prevented, Avoid working in rainy day.

3 For maintenance and replacement of parts of air conditioner, the same type produced by the same manufacture shall be used. They cannot be mixed with other parts. Check whether replaced parts conform to technical requirements. They shall have no hurt or damage. Good seal. Dry and clean inside.

4 During the whole maintenance process, prevent dust, water and dirt from entering system.

5 When connecting joints, you shall check whether seal ring is in good condition. Appropriate amount of refrigeration oil shall be smeared on O Ring (Type: SUNISO. 5GS with F and PAG without F) to prevent O Ring from damages. After refrigeration oil is used, guide part shall be inserted to the bottom. Connecting nut shall be tightened.

6 Nuts shall be tightened or screwed off with 2 wrenches. One wrench holds joint. The other wrench tightens or screws off nut. In the end tighten with torque wrench. Operation shall be completed according to specified torque. Joints of pipelines shall be tightened according to

specified tightening torque. See the table below for tightening torque.

Size of screw thread Tightening torque

5/8-18UNF 、 M16×1.5 16 ～ 20N.m

3/4-16UNF 、 M22×1.5 20 ～ 25N.m

7/8-14UNF 、 M24×1.5 30 ～ 35N.m

7 Pipelines and wirings shall keep away from heat source and rotating parts and avoid wear and crack. Pipelines shall not be tight. Two ends of hose shall be fixed with ribbon. The middle part shall be fixed with pipe clamp. Wirings shall be tied with ribbon.

8 Minimum bend radius of hose shall be paid attention to for installation. Avoid sudden turn to prevent pipelines from folding. Ensure proper direction to ensure pipelines are unblocked.

9 Protect electrical connections in maintenance. Avoid knocking. Connection of electrical lines shall be correct, reliable and firm.

3.1 Maintenance Notice

部门18 日期

3.2 Poor Refrigerating EffectSymptom Reason Measures

Fan of evaporator is normal

1. Belt is loosened Adjust

2. Leakage. Insufficient coolant Check leakage and supplement

3. High pressure is high and low pressuer is high 　

a. Cooling fins of condenser are dirty and blocked Clean

b. Fan of condenser stops Repair or replace

c. Too musch coolant Release appropriate amount

d. Air in system. Pressure gage shakesCheck leakage, release and supplement

e. Expansion valve opens too much Adjust or replace

4. High pressure is high and low pressuer is low 　

a. Expansion valve is dirty and blocked Clean or replace

b. Reservoir is dirty and blocked Replace

c. High pressure pipelines are blocked Repair or replace

5. High pressure low and low pressuer is low 　

a. Leakage. Insufficient coolant Check leakage and supplement

b. Expansion valve opens too little Repair or replace

c. Low pressure pipelines are blocked Repair or replace

d. Evaporator is blocked Repair or replace

6. High pressure low and low pressuer is high 　

a. Failure of compressor Repair or replace

Air volum of evaporator is insufficient

1. Outlet or inlet is blocked Remove blocking

2. Air outlet is blocked Remove blocking

3. Evaporator is frosting Repair

Refrigerating system starts or stops

unnormally

1. Air in system Vacuum supply

2. Temperature controller is disordered Adjust

3. Compressor relay doesn’t suck Repair or replace

部门19 日期

2.2 Poor Refrigerating Effect

Compressor relay doesn’t suck

→Repair or replace

Insufficient or too much coolant→

Check leakage, supplement or release

Belt is loosened→

Adjust

Air in system→

Vacuum supply

Temperature controller is disordered

→Adjust

Air inlet is blocked→Clean

Air outlet is blocked→Clean

Evaporator is frosting→Repair

Supple

ment

Vacuum Supply

Cooling fins of condenser are dirty and blocked

→Clean

Fan of condenser stops→Repair or replace

Expansion valve opens too much or too little. Dirty and blocked→Adjust and clean

High-pressure pipelines are blocked→Repair or replace

Low-pressure pipelines are blocked→Repair or replace

Reservoir is dirty and blocked→Replace

部门20 日期

3.3 No RefrigerationSymptom Reason Measures

Fan of evaporator is normalCompressor doesn’t work

1. Clutch of compressor slides Repair or replace

2. Wire lead drops Inspect and connect

3. Belt is broken Replace

4. Pressure switch moves 　

a. Too much leakage of coolant Check leakage and supplement

b. Too much Filling of coolant Replace damaged component

c. Switch is broken Replace damaged component

5. Temperature controller is broken 　

Fan of evaporator is normalCompressor works

1. Too much leakage of coolant Check leakage and supplement

2. Too much Filling of coolant Release appropriate amount

3. Compressor is broken Repair or replace

Fan of evaporator doesn’t rotateCompressor doesn’t work

1. Inlet wire power failure 　

a. Poor contact of earth wire Inspect and repair

b. Fuse is broken Inspect and replace

c. Power switch is broken Inspect and replace

Fan of evaporator doesn’t rotateCompressor works

1. Fan is broken Replace

2. Fuse is broken Replace

3. Switch of wind is broken Replace

4. Speed regulating resistance is broken Replace

部门21 日期

3.3 No RefrigerationToo much leakage of coolant

→Check leakage and supplement

Clutch of compressor is broken→Repair or replace

Compressor is broken→Repair or replace

Wire lead drops →Inspect and connect

Belt is broken→Replace

Pressure switch is broken→Replace damaged component

Temperature controller is broken→Replace

Fuse is broken→Inspect and replace

Poor contact of earth wire→Inspect and replace

Power switch is broken→Inspect and replace

Evaporator blower is broken→Replace

Wind switch is broken→Replace

Speed regulating resistance is broken→Replace

Suppl

emen

t

Circuit

部门22 日期

3.4 High Noise

Symptom Reason Measures

System makes abnormal noise

1. Belt is too loosened Adjust or replace

2. Compressor holder is loosened

Adjust

3. Wind wheel of evaporator fan is loosened

Adjust

4. Clutch slides Repair or replace

5. Wear inside of compressor Repair or replace

部门23 日期

3.4 High Noise

Belt is too loosened

→Adjust or replace

Compressor holder is loosened→Adjust

Wind wheel of evaporator fan is loosened

→Adjust

Wear inside of compressor→Replace

Clutch slides→Repair or replace

部门24 日期

4. Coolant Filling

部门25 日期

4. Coolant Filling

4.1 Creation of VacuumClose high-pressure valve (HI) and low-pressure valve (LO) of pipeline pressure test device, remove plastic cap of Filling connector valve on compressor, connect "B" of pipeline pressure test device to joint valve at low pressure side, and connect "C" to joint valve at high pressure side.Connect central filling hose "A" to the vacuum pump. Open low-pressure valve and high-pressure valve on pipeline pressure test device and valve on vacuum pump. Vacuum pump operates for about 15 minutes until reading of low-pressure gauge is about -0.1 MPa. After creation of vacuum, close high-pressure valve (HI) and low-pressure valve (LO) on pipeline pressure test device. Wait for 5 minutes. Make sure that readings of low pressure gauge do not change. It means that the system doesn’t have leakage. (Otherwise, there is leakage. Check leakage and repair.) Open the manual valve and continue to create vacuum for about 15 minutes. Notice that vacuum time shall be appropriately extended in damp weather according to humidity condition, in order to ensure vacuum requirement.

1. Low-pressure gauge 2. High-pressure gauge

3. Low-pressure valve (LO)

4. High-pressure valve (HI)

部门26 日期

4. Coolant Filling

4.2 Leakage Detecting

Close manual high-pressure valve. Indicator of pressure gauge has stable display. It shows the system doesn’t have leakage. If indicator of pressure gauge doesn’t have stable display. It shows there is leakage which has to be checked and repaired. If the indicator keeps still, open the manual valve and continue to create vacuum for 15-20 minutes.Caution: Creatioin time of vaccum must conform to requirement, to ensure that water in the system is completely dischareged. Create vaccum repeatedly in wet weather.

4.3 Coolant Filling （ R134a ）

Put stop cock on coolant container. Connect central filling hose of pipeline pressure test device to stop cock of coolant container. Rotate cock handle clockwise, so that bearing pin punches a hole on coolant container. And then rotate cock handle counter-clockwise to exit the bearing pin. Press air releasing valve core at the low-pressure valve side of pipeline pressure test device. Release air in the central hose with pressure of coolant.

The first time, coolant shall be filled in air conditioning duct from high-pressure side when the engine stops. In order to fill prescribed quantity of coolant, when the engine is running (compressor runs), continue to fill coolant from low-pressure side.

High-pressure side filling: When the engine stops, open high-pressure valve of pipeline pressure test device. Coolant shall enter the system from high-pressure side. At this time reading of low-pressure gauge rises slowly until prescribed quantity of coolant is filled or pressure cannot rise.

When coolant cannot be filled from high-pressure side, but prescribed quantity has not been reached, close high-pressure valve (HI) of pipeline pressure test device and stop cock of coolant container. Start the engine and open all the doors. Switch off air conditioner. Adjust switch of blower to MAX and temperature control rod to "COOL" (cooling). Adjust rotate speed of compressor to 1800 - 2000rpm. Open low-pressure valve (LO) of pipeline pressure test device. Fill coolant into the system until reading of high-pressure gauge of pipeline pressure test device is between 1.5-1.7 MPa. After filling, close low-pressure valve of pipeline pressure test device and valve of coolant container. And stop the engine.

部门27 日期

4. Coolant Filling

Coolant filling tools

1Fast coupler

2Vacuum pump

3Filling hose

4Coolant maintenance tank

部门28 日期

4. Coolant FillingA Release coolant

B Begin releasing

G Check gas tightness

Filling

Flow of Coolant D Check after 5-10 min

C Stop releasing （ -710mmHg ）

E Release air （ -750 ～ -760mmHg ）

J Check and adjust pipelines

F Add coolant （ about 200g ）

I Operation inspection

H Fill coolant

Pressure drops

Normal

Abnormal

Normal

Specified amount

部门29 日期

4. Coolant FillingCheck carefully whether there is leakage in pipelines of air conditioner with leak detector.

Check filing amount of coolant: Start the engine and open all the doors. Adjust air conditioning switch to "ON" (connected). Adjust air blower switch to "MAX" (Maximum) and adjust temperature control rod to "COOL" (coldest). Keep rotate speed of compressor around 1800rpm. Check filling amount of coolant through observation window according to flow of coolant. Remove pipelines of pressure test device. Notice that remove pipes fast to prevent too much coolant from flowing out. Gloves shall be worn when removing pipes to prevent frostbite.

Amount of coolant

Coolant state in observation window

Too much

Reading of low-pressure gauge is above 0.2MPa. Bubbles can be seen sometimes or no bubble

Appropriate

Reading of low-pressure gauge is between 0.15 and 0.2MPa. A small amount of bubbles can be seen

Insufficient

Reading of low-pressure gauge is below 0.1MPa. Continuous bubbles can be seen.

Liquid Observation Window

Too much Appropriate Insufficient

No coolant

部门30 日期

5. Security Matters

部门31 日期

5. Security Matters

4.1 Operator should wear protective glasses and gloves to avoid cold injury caused by sprayed liquid coolant.

4.2 Type designated by manufacturer shall be used. Coolant cannot mixed with other types. Filling amount of coolant should be according to air conditioning usage manuals of different manufacturers. Shall not add less or more.

4.3 Keep away from open light during operation to prevent dangerous accidents.

4.4 It is forbidden to fill coolant outdoor in rainy weather.

4.5 Steel cylinder shall not be inverted or tilted when filling with big tank in order to prevent sludge in bottle from flowing into air conditioning system and causing blocking.

4.6 It is not allowed to fill liquid coolant from low-pressure side when compressor operates. Otherwise, liquid impact may damage compressor. It may cause personal injury when serious. Only gas coolant can be filled in from low-pressure side when compressor operates.

4.7 When ambient temperature is low, as coolant flows out of bottle, pressure and temperature in the bottle will decrease, which will extend filling time. To improve efficiency, it can be heated with hot water, but temperature of hot water shall not exceed 49°C.

4.8 When gas coolant is filled in from low-pressure side while engine starts, high-pressure valve shall be closed.

4.9 To fill coolant under low temperature (ambient temperature is below 18°C), heating system shall be opened first. Close driver door. Fill coolant when temperature in cab is above 18C°.

4.10 Because readings of high-pressure and low-pressure gauge will be influenced by ambient temperature while filling, to ensure system pressure under which air conditioner can work normally, readings of high-pressure and low-pressure gauge under different ambient temperature shall be according to Table 1.

部门32 日期

5. Security Matters

Ambient temperature(temperature outside vehicle)

Reading of high-presssure gauge

Reading of low-presssure gauge

Celsius degree(°C) MPa MPa

20 1.2±0.2 0.15±0.02

25 1.4±0.2 0.18±0.02

30 1.6±0.2 0.20±0.02

35 1.8±0.2 0.22±0.02

40 2.0±0.2 0.25±0.02

Condition: When filling R134a coolant, rotate speed of compressor shall be 2000RPM. Maximum air volume and appropriate humidity

Table 1 Approximate scope of readings on pressure gauge

Equivalent value of different pressure intensity unit of high-pressure and low-pressure gauge

Unit name and symbol Relation

psi—British system pressure intensity （ pound/inch2 ）

1 Kg/cm2=14.22 psi

inHg-- British system negative pressure intensity （ inch, mmHg ）

1 inHg=25.4 mmHg

bar—metric system pressure intensity （ bar ，dyne/cm2 ）

1 Kg/cm2=0.98 bar

Pa--metric system pressure intensity （ Pa ，N/m2 ）

1 Kg/cm2=0.98×105 Pa

部门33 日期

If loader air conditioner produced by Shandong Lingong Construction Machinery Co. Ltd you are using has failure, please don’t hesitate to contact us.

E-mail: [email protected]

TEL: +86-0531-66590955-817

Address: Room 902, Building 9, No. 2000, Shuntai Square, High-tech Development Zone, Jinan, Shandong Province, China

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