How to solve the following problems encountered in the use of high and low temperature humidity chamber

The high and low temperature humidity environmental chamber is a test equipment in the fields of aviation, automobiles, home appliances, scientific research, etc., used to test and determine the temperature environment changes of electrical, electronic and other products and materials for high temperature, low temperature, alternating humidity and heat or constant test after the test parameters and performance. LISUN design high and low temperature humidity environmental chamber is according to IEC60068-2-1 (GB/T2423.1) and IEC60068-2-2 (GB/T2423.2), IEC60068-2-78, IEC60598-1, GB/T2423.17, GB/T5170.2, GB/T5170.5.

High and Low Temperature Humidity Chamber

1. During the damp heat test, the humidity does not meet the specific requirements. Where does the problem occur?
Analysis: If the high and low temperature alternating damp heat test chamber is doing the damp heat test, if it appears,
(1) The actual humidity will reach 100%
A. It may be caused by the dry gauze on the wet bulb sensor. It is necessary to check whether the water tank of the wet bulb sensor is lack of water. Whether the pump is working normally;
B. It may be due to the long use time of the wet ball gauze or the purity of the water supply, which will make the gauze hard and make the gauze unable to absorb water and dry. The above phenomenon can be eliminated by replacing or cleaning the gauze.

(2) The actual humidity is very different from the target humidity, and the value is much lower.
The humidification system of the high and low temperature alternating heat and humidity test chamber does not work. Check the water supply of the humidification system, whether there is a certain amount of water in the water supply system, and whether the water level control of the humidification water pan is normal. If everything above is normal, then check the electrical control system, which requires professional maintenance personnel to check.

2. How to solve the problem if the low temperature fails to reach the target and the temperature drops slowly?
Analysis: first need to observe the temperature changes
A. If the temperature drops slowly, you need to check the following points, whether the studio has been dried before the low temperature test, the studio must be dried before the test, and then put in the test sample for testing; whether the test sample in the workroom are placed too much which causing the wind in the working room to not be fully circulated, or the circulating fan does not rotate. Whether the static load in the box is too large, and whether the heating load in the box is too large. After eliminating the above reasons, it is necessary to consider whether it is a failure of the refrigeration system, and the maintenance of the refrigeration system requires the operation of professional personnel from the manufacturer.
B. If the temperature has a tendency to rise after reaching a certain value, first check whether it is caused by the use environment of the high and low temperature alternating damp and heat test chamber, and whether the ambient temperature and the placement position (the distance between the back of the box and the wall) of the equipment meet the requirements etc. (It is stipulated in the operation instructions of the equipment).

3. In the high temperature test, the temperature change does not reach the test temperature value, how to solve it?
Analysis: You can check the electrical system and troubleshoot one by one.
A. If the temperature rises very slowly, you need to check the air circulation system and whether the adjustment baffle of the air circulation is normally opened.
B. If the temperature rises quickly, check whether the air circulating motor is operating normally. If the temperature overshoot is severe, then you need to tune the PID setting parameters. If the temperature rises directly and the over-temperature protection is applied, then the controller fails and the controller must be replaced.

4. What should you do if the temperature control shows abnormal pressure?
Analysis: First of all, you need to check the location of the equipment, whether it is more than 30 cm away from the wall, because poor heat dissipation will cause the pressure on the high pressure side of the compressor to be too high, so if it is caused by improper placement, it needs to be adjusted in time. Secondly, Check whether there is a sealed space around the instrument. If it is a sealed space, it will cause temperature rise in the environment and excessive pressure on the high-pressure side of the compressor, so please keep the surroundings ventilated. If it is not the above fault, please ask a professional for maintenance.

The refrigeration system of the high and low temperature environmental chamber often has the following failures:
1. Caused by excessively high ambient temperature: The ambient temperature of the test chamber is clearly specified as 5℃-30℃. If the ambient temperature is too high, there will inevitably be a phenomenon that the low temperature cannot drop.
2. Slow heating without heating: Check whether the heating system is faulty, such as whether the heating tube is open, whether the heating tube wiring is loose, whether the control instrument is burned out, whether the circuit is open, etc.
3. Condenser fan failure: detect whether the fan motor is blocked or burned due to the fan’s non-rotating or reduced wind speed.
4. No moisture: first check the lack of water, then check whether the humidifier is normal, and then check the electronic control part.
5. Refrigerant liquid leakage: Coat the surface of the copper pipe with soapy water and detergent, detect the leakage point, repair the leak, and add the refrigerant liquid.
6. Only high temperature and not low temperature: When the compressor is working normally, it may be that the refrigerant in the compressor is insufficient, or the radiator is blocked, which causes poor heat dissipation, and then may be blocked or leaked in the pipeline. As long as there are targeted investigations and punishments, they will be dealt with one by one.
7. Uneven temperature and humidity in the box: It may be a problem with the stirring fan. First check the working condition of the fan. Check whether there is noise, whether the motor is damaged (such as burned), whether the bearing is out of oil, etc.
8. Compressor failure: Check whether the refrigeration compressor is working. If it fails, call the manufacturer to repair or replace the compressor.

The above are some common faults of this equipment. Of course, if you want fewer failures and a longer service life, regular maintenances are also indispensable.

Lisun Instruments Limited was found by LISUN GROUP in 2003. LISUN quality system has been strictly certified by ISO9001:2015. As a CIE Membership, LISUN products are designed based on CIE, IEC and other international or national standards. All products passed CE certificate and authenticated by the third party lab.

Our main products are Goniophotometer, Integrating Sphere, Spectroradiometer, Surge Generator, ESD Simulator, EMI Receiver, EMC Test Equipment, Electrical Safety Tester, Environmental Chamber, Temperature Chamber, Climate Chamber, Thermal Chamber, Salt Spray Test, Dust Test Chamber, Waterproof Test, RoHS Test (EDXRF), Glow Wire Test and Needle Flame Test.

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