Air Conditioning Troubleshooting and Repair - （空调故障诊断和维修,）.pdf

HVAC-02, Air Conditioning Troubleshooting and Repair Introduction Since Im constantly receiving questions on 944 air conditioning systems, I figured its time to come up with come helpful troubleshooting tips. Working on the 944 A/C system is no different than working on any other automotive A/C system. They have all the same components which function in the same manner as any other A/C system. First, if youre having a problem with the A/C system on your 944, there are two ways you can approach solving the problem. The first is to just start replacing components and hope you get lucky by replacing the faulty component the first time. The other method involves doing some actual testing to narrow down the cause of the problem. In order to properly test the A/C system and narrow down the possible causes of your problem, youre going to have to invest in a set of A/C gauges. Before we begin with the actual troubleshooting, to properly troubleshoot the A/C system, its extremely helpful to understand how the automobile A/C cycle works. So, well begin by discussing automotive air conditioning theory of operation. There are two basic types of automotive air conditioning systems. The type of system is determined by the device used to control the expansion of the high pressure, high temperature liquid to a low pressure, low temperature liquid. One system uses and expansion valve while the other uses an orifice tube. 944s use an expansion valve system. Well discuss the operation of both. The first component in the A/C cycle is the compressor. The compressor takes low temperature refrigerant gas and compresses it into a high pressure, high temperature gas. The refrigerant is then sent to the condenser which sits in front of the radiator. The condenser removes some of the heat from the refrigerant which causes the refrigerant to change phase from a hot gas to a warm liquid. In the expansion valve A/C system, the warm liquid is then passed t