How to judge the quality of the air conditioner temperature sensor?
Air-conditioning temperature sensor is a sensor that converts temperature into electricity by using the laws that various physical properties of substances change with temperature. These physical properties that show regular changes are mainly physical. Temperature sensor is the core part of temperature measuring instrument, and there are many varieties. According to the measurement method, it can be divided into two categories: contact type and non-contact type. According to the characteristics of sensor materials and electronic components, it can be divided into two types: thermal resistance and thermocouple.
Thermal resistance type temperature sensor Thermal resistance type temperature sensor is divided into two types: metal thermal resistance and semiconductor thermistor. The resistance of most metal thermal resistors increases with the increase in temperature, and is said to have a positive temperature coefficient; while the resistance of semiconductor thermistors generally decreases with the increase in temperature and is said to have a negative temperature coefficient. Since the resistance of conductors and semiconductors changes with temperature, the corresponding temperature can be measured by measuring their resistance.
How to judge the air conditioner temperature sensor
The editor specially compiled an article on how to judge the quality of the air conditioner temperature sensor. When judging the performance of the air conditioner temperature sensor, the fixed frequency air conditioner should be set to a forced cooling operating state, and the inverter air conditioner should be set to a trial run operating state. If the air conditioner can operate after this setting, and the operating current is basically normal, it is generally considered that the temperature sensor has a problem. An increase in the resistance value of the air-conditioning temperature sensor or a decrease in the resistance value of the compressor temperature sensor will cause the output frequency of the inverter to be lower and affect the cooling effect. Of course, there are other ways to judge whether the sensor is good, and then I will talk about these methods:
Analog method to judge whether the sensor is good
According to the temperature detected by various temperature sensors or artificially simulated temperature, analyze whether the temperature and resistance change curve is normal, so as to judge whether the temperature sensor is bad. The rule is: temperature is inversely proportional to resistance.
Determine the sensor quality according to the CPU input voltage
Analyze whether the current temperature is correct according to the voltage value of the single-chip microcomputer cPu input by various temperature sensors to determine whether the temperature sensor is defective. The law is: temperature is proportional to voltage.
What is the resistance of the air-conditioning temperature sensor
In the work of air conditioning maintenance, many air conditioning maintenance technicians just replace the temperature sensor according to the resistance value. In fact, there is a major misunderstanding here. In addition to the resistance value of the air conditioning temperature sensor, there is another key parameter: the temperature coefficient B value. The temperature coefficient B value refers to the change rate of the resistance increase with the temperature resistance when the temperature increases by one degree. The most popular air conditioner manufacturers are 3435, 3450, 3470, 3950, 3960 and so on. The same resistance value, the temperature coefficient B value is different, under different temperature conditions, the resistance value changes greatly. During air conditioning maintenance, if the resistance value and the temperature coefficient B are selected incorrectly, it may cause the air conditioning unit to fail to operate normally or to work abnormally in a certain temperature area. Loss of key protection will eventually lead to damage to the key components of the unit and cause heavy economic losses to users.
In the air conditioning repair work, when the air conditioning temperature sensor is damaged, how to detect the original specification parameter resistance and B value of the air conditioning temperature sensor on the spot. Is very important. Only when the correct temperature sensor specifications are selected can the air conditioning unit resume normal operation. Avoid the air conditioning unit from causing multiple potential failures due to the incorrect selection of the temperature sensor and unable to operate stably.
When we are repairing air conditioners, we often find various intractable diseases of air conditioners. For example, the user reports that the air-conditioning unit has normal cooling but abnormal heating. Or often report some temperature-related failures. In fact, most of these failures are related to the last repairer's temperature sensor selection error. If the specifications of the original temperature sensor of the air conditioning unit manufacturer can be detected on site, we can replace the temperature sensor correctly. Avoid the occurrence of intractable air-conditioning diseases.
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