No matter how good a product is, when something goes wrong, how to distinguish the faults quickly and make the experimental equipment adhere to a good working condition has always been a research topic for the manufacturers of environmental experimental equipment. Based on years of after-sales service experience, the following common faults and solutions are summarized:

Firstly, the low temperature of the constant temperature and humidity experimental box can not reach the experimental principle. First, we should observe the change of temperature, whether the temperature drops very slowly, or the temperature tends to rise after the temperature reaches a certain value. The former should check whether the operating room is dried before doing the low temperature experiment, so that the operating room insists on drying and then puts the experimental samples into the operating room before doing the experiment. The experimental samples in the operating room are as follows: If there is too much air in the working room, it will not be able to circulate adequately. After removing the above reasons, we should consider whether there is a problem in the refrigeration system, so we need to ask professionals to repair it. The latter phenomenon is caused by the poor use environment of the equipment. The environmental temperature of the equipment and the position of the equipment (the space between the back of the box and the wall) should meet the requirements (which are explained in detail in the equipment use description).

2. In the experiment of constant temperature and humidity, the actual humidity will reach 100% or the difference between the actual humidity and the guideline humidity is very large, and the value is much lower. The former phenomenon may be caused by the drying of gauze on the wet bulb sensor. It is necessary to check whether there is water shortage in the wet bulb sensor tank. The water level in the tank is automatically controlled by a water level controller, and check the water level control. Whether the water supply system is normal or not, and whether the operation of the water level controller is normal. Another possibility is that the wet ball gauze will harden due to its long use time or the purity of water supply, so that the gauze can not absorb moisture and dry. The above phenomenon can be swept away by replacing or cleaning the gauze. The latter phenomenon is mainly that the humidification system does not work, check the water supply system of the humidification system, whether there is a certain amount of water in the water supply system, whether the water level control of the humidification boiler is normal, whether the water level in the humidification boiler is normal. If all the above is normal, you should check the electrical control system, which requires professional repairmen to check.

3. When the constant temperature and humidity test box suddenly appears faults during the operation of the experiment, the corresponding faults display prompts and audio alarm prompts appear on the control instrument. Operators can quickly see which kind of faults they belong to in the chapter of cleaning up the faults in the operation and use of the equipment, and then ask professionals to quickly clean up the faults so as to ensure the normal operation of the experiment. There will be other phenomena in the use of other environmental experimental equipment, so we need to analyze and eliminate specific phenomena. Environmental experimental equipment should also be regularly protected and maintained, the condenser of refrigeration system should be regularly arranged, the moving parts should be lubricated according to the instructions, the electrical control system should be regularly protected and inspected, and so on. These operations are indispensable.

4. The constant temperature and humidity test box can check the electrical system and remove the faults one by one in the high temperature experiment if the temperature change can not reach the experimental temperature value. If the temperature rises very slowly, we should check the wind cycle system, see whether the conditioning baffle of the wind cycle is open normally, and vice versa, check whether the motor of the wind cycle is running normally. If the temperature overshoot is fierce, the setting parameters of PID need to be adjusted. If the temperature rises directly and overtemperature is protected, then

Does the test preparation materials and the collection of real questions for the Engineers'Examination of all trades and professions in 2014 require the replacement of the controller if there is something wrong with the controller?

5. Reasons for the non-refrigeration of the constant temperature and humidity test box: 1.

1. Because the temperature can not hold fast, observe whether the refrigeration compressor can start during the operation of the test box, and the compressor can start during the operation of the environmental test equipment. It is clarified that the electrical circuit from the main power supply to the compressors is normal, and there is no problem in the electrical system.

2. There is no problem with the electrical system. Keep looking at the refrigeration system. First of all, the exhaust and suction pressure of two groups of low temperature (R23) compressors are lower than the normal value, and the suction pressure is empty, so the cooling dose of the main refrigeration unit is insufficient.

3. Touch the exhaust and suction pipeline of the R23 compressor of the main engine group by hand, and find that the temperature of the exhaust pipeline is not high, and the temperature of the suction pipeline is not low (not frosted), which also clarifies the lack of refrigerant in the main engine group (R23).

Reason two:

1. The cause of hair pathogen has not been determined. Combining with the control process of the experimental box, the cause of hair pathogen is further recognized. The experimental box has two refrigeration units.

2. One is the main unit and the other is the auxiliary unit. When the cooling rate is high, the two groups of units work together. At the beginning of the temperature persistence stage, the two groups of units still work together. When the temperature is initially stabilized, the auxiliary unit stops operation, and the main unit maintains the temperature stability. If the main unit R23 leaks, the refrigeration effect of the main unit will be small, because in the cooling process, the two units work together, so there is no phenomenon that the temperature can not be stabilized, and the cooling rate is indicated to be reduced. In the stage of temperature persistence, once the auxiliary unit stops operation and the main unit has no refrigeration effect, the air in the test box will rise slowly. When the temperature rises to a certain level, the control system will start the auxiliary unit to cool down, and then the auxiliary unit stops operation again. Such repetition will lead to the phenomenon of faults. Up to now, it has been admitted that the cause of the production fault is the leakage of refrigerant R23 from the low temperature (R23) class unit of the main engine group. Leak detection of refrigeration system was carried out, and the valve stem of a hot gas bypass solenoid valve was found to be cracked by the combination of leak detector and soap water. Replace the solenoid valve, refill the system with fluorine, and the system works normally.