In refrigeration and air conditioning systems, the temperature of each unit component is maintained within a specific normal range, which is an important guarantee for the stable operation of the system. Once these temperatures exceed the normal range, it may indicate a system malfunction or improper adjustment, requiring immediate cause analysis and handling. Due to the difficulty of directly measuring temperature points through thermometers, technicians rely on tactile feedback to make preliminary estimates.

1、 Exhaust temperature

Exhaust temperature is an important indicator for measuring the operating status of a compressor. In high temperature seasons such as summer, the exhaust temperature of the compressor may be relatively high, even to the point where it cannot be touched by hand. The high exhaust temperature is usually caused by the high suction temperature or high condensation temperature of the compressor. This situation requires high attention, as excessively high exhaust temperatures not only affect the efficiency of the compressor, but may also cause damage to its internal components.

If the exhaust temperature is too low, that is, the exhaust pipe is not hot to touch, it may indicate that the suction temperature is particularly low, the compressor may be in a wet stroke operating state, or the system refrigerant may be severely insufficient. Wet stroke operation can easily damage the compressor valve structure, while insufficient refrigerant can affect the heat dissipation of the motor winding and accelerate the aging of the insulation material.

2、 Compressor shell temperature

The temperature variation of the compressor casing has a significant impact on the overall performance of the compressor and refrigeration system. The temperature field on the outer surface of the fully enclosed compressor casing can be divided into two parts: the upper casing is affected by the suction steam and has a lower temperature; The lower casing has a higher temperature due to the heating of the electric motor and the frictional heat carried out by the refrigeration oil.

The high temperature of the casing is usually caused by the high suction temperature of the refrigeration system, which can affect the cooling effect of the oil and thus affect the lubrication and wear of moving parts. In severe cases, it may even lead to serious malfunctions such as bearing jamming. On the contrary, if the temperature of the casing is too low, it may be due to a low suction temperature. Although this is beneficial for cooling the refrigeration oil and motor windings, it can lead to a decrease in cooling capacity and may cause dangerous situations such as liquid hammer.

3、 Condensation temperature

The condenser is one of the key components in the refrigeration system, and its temperature directly reflects the heat dissipation effect of the system. Under normal circumstances, the front half of the condenser's heat dissipation pipe is very hot, and the temperature gradually decreases; The thermal sensitivity of the rear half of the heat dissipation tube is significantly reduced.

If the front half of the condenser is not too hot or the back half is close to room temperature, it may be due to the compressor sucking in wet vapor refrigerant or insufficient refrigerant. If the entire condenser tube is very hot, it may be caused by factors such as excessive refrigerant, low ventilation, or high ambient temperature.

4、 Condenser shell temperature

The normal range of shell temperature varies for different types of condensers. For example, under normal circumstances, the shell of a shell and tube condenser is relatively hot in the upper half and warm in the lower half; The fins of the air-cooled finned condenser are relatively hot in the upper half and warm in the lower half.

If the temperature of the condenser shell is abnormal, it may be caused by insufficient refrigerant, insufficient cooling water, or poor heat dissipation effect. At this point, it is necessary to promptly check and adjust system parameters to ensure the normal operation of the system.

5、 Temperature status of liquid tube and filter

Under normal circumstances, the liquid tube is in a warm state. If the liquid tube is relatively hot, it may be due to poor heat dissipation from the condenser, high condensation temperature, or excessive refrigerant flow.

As one of the key components in the refrigeration system, the temperature condition of the filter directly reflects the operating status of the system. Under normal circumstances, the temperature conditions of the filter and infusion tube are basically the same. But if the filter is cold or not hot, it may be due to the filter mesh being blocked by sludge or blocked. In this case, it is necessary to clean or replace the filter screen in a timely manner to ensure the normal operation of the system.

6、 Temperature condition of the suction pipe

The temperature condition of the suction pipe is one of the important criteria for determining whether the refrigeration system is operating normally. Under normal circumstances, the suction tube feels very cold and has dew buildup when touched by hand. If the suction pipe is too cold and there is too much dew, causing extensive condensation on the casing; Or if the suction pipe is not cool, does not condense, and the casing is very hot, it may be due to a low refrigerant flow rate or insufficient refrigerant dosage. In this case, it is necessary to replenish refrigerant or adjust system parameters in a timely manner to ensure the normal operation of the system.

7、 Temperature and evaporation temperature of thermal expansion valve

Thermal expansion valve is one of the key regulating components in refrigeration systems. Under normal circumstances, the lower half of the expansion valve body is very cold and has accumulated dew, and the sound of refrigerant flow is very dull. If the valve body is relatively cold and has a lot of dew or even frost on the surface, or if there is no sound of refrigerant flow but only gas flow, it may be due to clogged filter screens or refrigerant leakage in the power box. In this case, it is necessary to clean or replace the filter screen in a timely manner and check the refrigerant inside the power box.

8、 Temperature condition of evaporator

The evaporator is another key component in the refrigeration system. Under normal circumstances, the outer surface of the evaporator is very cold and condensation droplets continuously drip down, resulting in a large temperature difference between the inlet and outlet air. If the surface of the evaporator is not too cold, there is not much dew or condensation, and the sound of refrigerant flow can be heard loudly, and the temperature difference between the inlet and outlet air is small, it may be due to insufficient refrigerant or small opening of the expansion valve. In this case, it is necessary to promptly replenish refrigerant or adjust the opening of the expansion valve to ensure the normal operation of the system.

9、 Environmental temperature requirements for outdoor units

As an important component of the refrigeration system, the operation status of outdoor units is directly affected by the ambient temperature. According to national standards, outdoor units should ensure normal operation and meet the cooling capacity and other indicators indicated on the product nameplate when the ambient temperature is below 35 ℃. When the ambient temperature is within the range of 35-43 ℃, although the air conditioning unit can operate, it cannot guarantee the cooling capacity indicated on its nameplate; When the outdoor temperature exceeds 43 ℃, the air conditioning unit may be in an overloaded state and cause the electronic control protection device to operate, cutting off the power and stopping the operation. Therefore, when using air conditioning, it is necessary to pay attention to changes in outdoor environmental temperature and adjust the operating status of the air conditioning in a timely manner to avoid overload operation and the action of electronic control protection devices.