In the process of using the constant temperature and humidity test chamber, many laboratories will find that the temperature and humidity of the test chamber does not rise but fall. Why would this happen? To sum up the following four points.
First, the temperature of the constant temperature tank is not high. In the test process, if the temperature change does not reach the required test temperature value, you can check the electrical system of the thermostat equipment and troubleshoot one by one. If the temperature rises very slowly, check the air circulation system of the thermostatic equipment to see if the regulating flap of the air circulation of the thermostatic equipment is opened normally. Otherwise, check whether the motor of the thermostatic air circulation is operating normally. If the temperature is too high, the parameters of the thermostat PID need to be set. If the temperature rises directly and is too high, then the controller is malfunctioning and the control instrument must be replaced.
Second, the thermostat tank is not to low temperature to reach the test index, then we must observe the temperature change of the thermostat tank, the temperature is very slow, or the temperature reaches a certain value after a rising trend, the former must carefully check whether the studio is dry before the low temperature test, keep the studio dry, and then put the test sample into the work room and then test. If there are too many specimens in the work room, the air in the work room will not be enough. Cycle, after excluding the above reasons, consider whether it is the failure of the cooling system, so ask the factory professionals to repair. The latter phenomenon is caused by the improper use of the equipment.
The ambient temperature of the equipment placed and the location where it is placed (the distance between the back of the cabinet and the wall) must meet the requirements (specified in the instruction manual of the equipment).
The humidity of the thermostat does not rise, the humidity does not rise, it should be humidification heating tube does not work. Check whether the heating tube is open circuit, whether there is a break in the heating circuit, whether the fuse is burnt out due to short circuit; if the fuse is burnt out, check whether the solid state relay is bad during maintenance; if the main circuit is normal, check whether the output of the controller is damaged. Fourth, the humidity of the thermostat in the wet and hot test can not go down, the actual humidity will reach 100% or the actual humidity and the target humidity is very different, the value is much lower, the former phenomenon: may be caused by the drying of the gauze on the wet bulb sensor Then, check whether the wet bulb sensor water tank is short of water. The water level in the tank is automatically controlled by the water level controller. Check whether the water level controller's water supply system is normal and whether the water level controller is working properly. Another possibility is that the wet gauze has hardened due to long use or the purity of the water supply, making the gauze hard and the gauze cannot absorb water and dry. The above phenomenon can be eliminated by replacing or cleaning the gauze. The latter phenomenon is mainly because the humidification system does not work. Check the water supply system of humidifying system, whether there is a certain amount of water in the water supply system, whether the water level control of humidifying boiler is normal or not. If all of the above is normal, the electric control system should be checked and should be repaired by professional maintenance personnel.
Post time: Mar-23-2023
