Diagnostics and repair of air conditioning systems - temperatures in the system.

INTRODUCTION

The correct operation of the air conditioning system is determined by the change in the state of aggregation of the refrigerant, which occurs during changes in pressure and temperature inside the entire system. Among the key factors determining this process, temperature should be distinguished, and component diagnostics based on it can be considered one of the basic methods of diagnosing incorrect operation of the system. This is an easy, reliable and economical method, as the temperature ranges of individual components can indicate where potential problems are or where problems may arise in the near future.

SYSTEM COMPONENTS AND THEIR CORRECT OPERATING TEMPERATURES COMMON FAULTS

Depending on the high-pressure or low-pressure side, each component has a nominal temperature range within which it operates properly. Temperatures outside the nominal range - can indicate a number of potential problems related to the component, other components in the system or consumables used. The most common result of a malfunction is usually poor system performance, which means that there is not enough cool air in the vehicle cabin.

TYPICAL CAUSES OF INCORRECT TEMPERATURES OF INDIVIDUAL SYSTEM COMPONENTS

• Incorrect amount of refrigerant in the system.
• Improper use of additives - mainly excessive amount of UV dye causing overpressure in the system.
• Internal blockages of individual components and the entire system - caused by contamination, moisture or corrosion, carbonized oil, as well as improper use of additives (sealing agents) - the components most often exposed to clogging are: expansion valve, filter/drier and condenser (microtube technology).
• Condenser fan failure.
• Damage to the air circulation system - cabin filter, cabin blower, etc.
• Damage to the compressor - clutch, pistons, valve plate.
• Damaged condenser - limited heat transfer caused by missing or corroded louvers, dirty surface, leaks, bent louver tubes, etc.

RECOMMENDED SOLUTION

To ensure effective temperature diagnostics, Nissens recommends that several conditions be met before performing a temperature check. Firstly, the diagnosing person should analyze the structure of the entire vehicle system in order to determine the location of individual elements and ensure free access to them for the temperature measuring device. Second, the engine must be running, idling, and the cold air production and fan operation must be set to maximum. The engine should reach the correct operating temperature, which is usually in the range of 80 - 90°C. There are several places where temperatures should be measured: on the surfaces of individual components, at their outlets and inlets, and on ducts. For more detailed instructions and proper component operating temperatures, refer to the Nissens technical poster, A/C Temperature Diagnosis, available from distributors worldwide or at www.nissens.com/climate

More about products and services at www.nissens.com/climate and www.nissens.com.pl