Automotive air conditioning maintenance inspection procedures and cautions

1. The maintenance and inspection procedures

The maintenance procedures has been proved to be based on the principle----- First inspect simple problems, then complex problems; first check externally, then internally; the first electrical circuit, after the refrigeration system, which is more scientific. It can be divided into four stages, namely, to determine the fault position, find the cause of the malfunction, processing troubleshooting, inspection and adjusting. Maintenance staff also check the following aspects:
1). Visual inspection of the system, in particular, to check the tightness of the compressor belt; brackets, fasteners, hoses, brass soundness; whether the radiator of condenser and evaporator is blocked; the oil consumption of compressor, and the outlet duct degree of flexibility and control institutions, the working condition of fans and motors; whether air filter is clean or with obviously leaking spots.
2). To check system, in particular, to check whether refrigerant charge is in compliance with standards, to check the temperature of high and low pressure side.
3). Check the electrical control system, with the naked eye to observe whether the radiator fuse is blown.; with a Multimeter to measure whether coil resistance value of clutch in compliance with the standards.

2. Maintenance cautions:

1). Service to wear protective glasses
2). Don’t open cooling system in the rainy or around waters.
3). Dryers must be installed in the final
4). Refrigeration system must be stamped seal timely after opened
5). Freezer oil to be covered tightly at any time.
6). Repair tools must be clean and dry
7). Refrigerant should be stored below 40℃ environment.
8). Refrigerant to be discharged slowly to prevent freezing the oil away
9). Handling refrigerant not in a sealed room or near the place of the flame
10).Don’t add liquid refrigerant from low-pressure side, don’t operate compressor while adding refrigerant from high pressure side.

3. Common failure of Air conditioning to offer

When the panel displays ER01:
1) View and check whether the compressor and the generator belt is loose, whether loose, tighten the belt to the proper position, re-open the air to see whether the problem exists;
2) To exclude the case of belt loosen,  further check harness around the generator whether there is virtual access, Ground phenomenon; check whether air conditioning large fuse around generators is damaged;
3) View and check the outlet back to the fuse and relay K40 is damaged; whether these issues are excluded, please contact the maintenance staff to solve;
When the panel appears ER04 alarm:
1) Re-disassembly digital panel,  to check whether the connectors are loosen;
2) Check whether low pressure switch cable of compressor is damaged;
3) Check whether there is refrigerant leakage around compressor pipes; Whether the above problems are excluded, please contact the maintenance staff to solve;

4. Air Conditioning Maintenance Knowledge in Four Season

In Spring: When air conditioning in the early running, check whether the compressor oil is clear and transparent without black deterioration phenomenon; check whether oil level is normal (about 1 / 3); check whether pipe is loose on the interface, with or without traces of oil leakage phenomenon; check whether there is phenomenon of insulation off connectors and wire; check whether the air flow is consistent with the usual; check whether the belt is loose; check whether evaporator and condenser are dirty.
Note:  Before the use of air conditioning, the compressor clutch should be running slowly by hand or tool, in order to facilitate oil lubrication and avoid compressor damaged when starting the air conditioner.

In Summer: Air conditioning is running in peak season, one week as the standard, to check whether pipe’s interfaces, check whether compressor ‘s conditions is normal, check whether the harness is loose and to be tighten the interface; Cleaning file filters, suction filters once a month, which helps air conditioning cooling effect; 

 In Autumn: The use of air conditioning is low season. Mainly to check to ensure the amount of compressor oil and its quality without black deterioration phenomenon. Check whether the pipe connector’s screws are loose; check  whether there is oil leakage phenomena. Cleaning once a month file filters, suction filters, to facilitate the use of air conditioning for the wind.
 
 In Winter: Winter is the off-season for air-conditioning use. Do not remove the compressor belt in winter; monthly check the compressor oil, forced air cooling system running for more than 10-30 minutes at least once a month to ensure adequate lubrication of the interfaces pipeline system, to effectively prevent parts lubricated parts from lacking of oil .

5. Frequently Asked Questions of Drivers

Q: Why sometimes there is dripping phenomenon at air outlet?
A: Due to there is water inside air circulation system, it should remove moisture if there is dripping, indicating poor drainage, it is needed to clean the drains and dirt timely.
Q: Why air conditioning would odor sometimes?
A: There are several reasons: 1, internal reasons, the evaporator refrigerant leakage. Although the refrigerant itself without any smell, the leakage of refrigerant is accompanied with oil leaking, and it will produce odor due to frozen oil deteriorated because of water or impurities inside.
2, External causes, such as exhausting from vehicle outside or maybe also be it stinks from some sort of dead animals or rat in it.
Q: What is the role of air conditioning belt?
A: The power of engine crankshaft rotation is driven by compressor of air conditioning through belt driven. In general, drivers need to regularly check the air conditioning belt tightness. When slipping belt will be too loose, will issue ear-piercing sound when air conditioning running; If belt too tight will damage the air conditioning compressor bearings. Please make adjustments timely.

6. Cleaning procedures and precautions for coil and air filter of air conditioning

1). condenser cleaning 
a Remove the condenser fan or condenser fan will be protected with plastic sheeting; 
b Washing off the radiator by high pressure water rinse.  To control the pressure not to damage the radiator too. Such as congested, you need to firstly scrape oil off, and then add a neutral detergent.
2), the evaporator cleaning
Evaporator cleaning steps: 
a Remove the evaporator fan or to protect the fan with plastic sheeting 
b Protect the electronic control box and air return with plastic sheeting from water back; others is also applied the procedures of the condenser cleaning method.
3), filter cleaning
Generally include return air-gate filter and the filter of evaporator coil.
Check the cleaness of dust-degree block, remove the block filters, it is need to use compressed air to clean the block dust filters.
If it is dirty or clogged, place it in warm water mixed with mild detergent in wash, rinse it with water and dry completely, then install and recovery.