What is the reason why the constant temperature and humidity test chamber is not refrigerated?

The reason why the constant temperature and humidity test chamber is not refrigerated is due to the use of too long, three or five years, lack of maintenance, which will inevitably lead to the occurrence of the constant temperature and humidity test chamber is not refrigerated.

Check 1: When the temperature of the constant temperature and humidity chamber cannot be maintained, for example, the temperature is set to minus 20 degrees, but it has only stayed at room temperature of 20 degrees or 10 degrees, and cannot reach the preset low temperature range, we should first observe whether the refrigeration compressor can be started during the operation of the test chamber? If the compressor can be started during the operation of the environmental test equipment, it means that the electrical wiring from the main power supply to each compressor is normal, and there is no problem with the electrical system.

Check 2: There is no problem with the electrical system of the constant temperature and humidity test chamber, and in the next step, we continue to check the refrigeration system. First of all, check that the exhaust and suction pressures of the cryogenic compressors of the two groups of refrigeration units are lower than the normal values, and the suction pressure is in a state of evacuation, indicating that the refrigeration dose of the main refrigeration unit is insufficient, and the refrigerant needs to be increased.

Check 3: touch the exhaust and suction pipes of the compressor of the main engine group with your hands, if the temperature of the exhaust pipeline is not high, the temperature of the suction pipeline is not low (not frosted), which also indicates that the R23 refrigerant of the main engine group is lacking, and it is necessary to contact the manufacturer to charge the refrigerant.

Of course, for the comprehensive overhaul of the constant temperature and humidity test chamber, it is best to let the constant temperature and humidity test chamber manufacturers send professional technicians to overhaul, because since it is filled with refrigerant, it also involves the skills, if the filling is not good, it is easy to lead to insufficient or uneven filling of the refrigerant, and it will also be easy to cause many details of the problem.

Reason: Because the temperature of the test chamber cannot be maintained, observe whether the refrigeration compressor can be started during operation, and the compressor can be started during the operation of the environmental test equipment, which proves that the electrical wiring from the main power supply to the compressor is normal, and there is no problem with the electrical system.

There is no problem with the electrical system, check the cooling system. First of all, check that the exhaust and suction pressure of the low-temperature (R23) compressor of the two groups of refrigeration units are lower than the normal value, and the suction pressure is in a vacuum state, which proves that the refrigeration dose of the refrigeration unit is insufficient to touch the exhaust and suction pipes of the R23 compressor of the host group, the exhaust pipe temperature is not high, and the suction temperature is not low (no frosting), which also indicates that the R23 refrigerant of the main engine group is insufficient.

The sensor near the sink is a humidity sensor, and the gauze should be hung on the humidity sensor and cover the temperature sensing part of the sensor. There are a small number of users often hang the gauze in the wrong position and hang it on the temperature compass reed sensor, causing the machine to malfunction, so please carefully identify the temperature probe on the top and the humidity probe near the sink below. Two:

If the hanging method is correct, the humidity still shows 100, please check whether the wet bulb gauze is yellowing, or if it is used for too long, too many minerals accumulate on the gauze, resulting in a decrease in the water absorption performance of the wet bulb gauze, and it cannot absorb water, so that the detected humidity is inaccurate, resulting in the illusion of high humidity, if not, please replace the wet bulb gauze, if not, you need to check that there is no water in the wet bulb sink or the water level is low, and the gauze cannot absorb water, focus on the following parts: a. Observe whether there is water in the water level box on the side of the sink, if not, It is possible that the float is damaged b, the electromagnetic pump is damaged, and the voltage level of the multimeter is used to measure its resistance, if the open circuit is damaged, the mountain belt is damaged, the gap water replenishment timer is damaged, and the water can not be replenished normally Three: there is also a problem with the controller setting, there are a few customers who have a misunderstanding of the use of the constant temperature and humidity test chamber, often do low temperature and set humidity, high temperature 120 degrees Celsius also set humidity, this situation will also cause the controller to be inaccurate and unstable.

The low temperature machine cannot control the humidity, it is easy to freeze and evaporate too quickly at high temperature, and it is very difficult for the machine to set the humidity. Therefore, please read the instructions carefully, standardize the operation of the machine, and prolong the service life of the equipment. I hope it can help you and wish you a happy life and good health.

According to the above principle, the key to humidity control is the cloth, and many problems of uncontrolled humidity are caused by the wet bulb cloth, because there needs to be moisture evaporation on the wet bulb cloth, so the wet bulb cloth must be moist and moisture. There is a small sink below the wet ball, and the lower part of the wet ball cloth is immersed in the bottom of the tank, continuously absorbing water from the tank, so the key point is to see if there is water in the tank, if not, the problem of failure is that there is no water in the tank, so in this case, add water to the sink to the front of the Li Yi. Usually every time we send a piece of equipment, we will tell the customer when teaching the machine that the wet bulb gauze should be replaced regularly, and it should be replaced when the gauze becomes dry and hard, generally once every three months, to avoid not sensing humidity.

As long as the cause is found, it is still very simple to solve, so don't underestimate this piece of gauze, a small thing, it is very useful.

The constant temperature and humidity test chamber is the main equipment in the temperature and humidity environment test, mainly for temperature and humidity test, so as to evaluate the temperature resistance and humidity resistance of the product, so as to ensure that the product can work and run normally under any environmental conditions. However, if the temperature uniformity of the liquid exceeds the allowable deviation range during the environmental test of the constant temperature and damp heat test chamber, then the data obtained from the test is unreliable, and the test data cannot be used as the limit tolerance of the humidity and temperature test of materials or products.

Briefly introduce what are the reasons that will cause the temperature uniformity to exceed the allowable deviation range, and the difference of test objects in the work room of the constant temperature and humidity test chamber: if the test sample that affects the overall internal heat convection is placed in the test chamber workshop, it will inevitably affect the uniformity of the internal temperature to a certain extent, that is, the temperature uniformity. For example, if LED lighting products are placed, the product itself has a heat load due to chaotic light and heat, which has a great impact on the uniformity of temperature.

The design problems make it difficult to achieve a uniform symmetrical structure in the structural design of the internal space of the constant temperature and damp heat test chamber, and the asymmetrical structure will inevitably lead to the deviation of the internal temperature uniformity. This aspect is mainly reflected in the sheet metal design and sheet metal treatment, such as the design of the air duct, the installation position of the heating pipe, and the power of the fan. will affect the temperature uniformity in the box.

Control the humidity of the test chamber by the instrument signal output to the solid state relay, and then by the solid state control the heating tube work, you can check whether the heating tube is burned out, whether the water level is normal, whether the solid state has on-off output. The instrument generally does not have problems, as long as the setting and water level are normal, it will give a solid-state voltage signal. You can contact me for details.

Constant temperature and humidity test chamber leakage, humidity can not go down the cause and solution:

1. The reason for the leakage of the constant temperature and humidity test chamber is that the water tank is not well sealed, leakage, or the water pipe is not connected well and the water pipe bursts.

First of all, you should check the source of the water leak, and then observe the water tank, humidifier, and water level box. Find the problem and find a professional repairer to deal with it.

2. The humidity of the constant temperature and humidity test chamber does not drop for the following reasons:

The compressor is not refrigerated, there is no cold air, and the humidity naturally cannot be lowered. The refrigeration system needs to be overhauled;

There are two sensors at the air outlet in the box, check whether the wet cloth of the humidity sensor hanging below has moisture, if it dries, the humidity will be displayed very high, showing 100%. The sensor needs to be humidified;

Check the solid state relay that controls humidity for breakdown. The breakdown relay needs to be replaced.

According to many years of experience, the leakage of the constant temperature and humidity test chamber has the following situations:

1. The humidifier seal is damaged and needs to be replaced;

2. If the water level control box is leaking abnormally, adjust or replace the water level box;

3. The inner cabin is not tightly sealed, and water leakage occurs after a long time of high temperature and high humidity test, which is often accompanied by water rust stains. This phenomenon is recommended to find a manufacturer to solve, because it is necessary to replace the insulation cotton (which is fully wet, which affects the insulation effect), and it is necessary to find the leakage point and seal it with silicone, otherwise it will soon be a failure.

The humidity can not go down and the constant temperature and humidity test chamber leakage has little to do with the high temperature and high humidity conditions when the PV value is higher than the SP value, and the actual humidity is not large, which may be due to the high humidity value is not installed or the gauze water absorption is not good, resulting in high humidity value, and the low humidity test humidity does not decrease for the dehumidification system to work abnormally, usually caused by the lack of fluorine in the refrigeration unit. Because there is very little information provided, there is only so much to reply.

Do you see where the leak is the water tank? Humidifier? Water level box?

Secondly, to solve the problem of humidity does not come, the general humidity does not come down for the following reasons: 1. The compressor is not refrigerated, there is no cold air, and the humidity will naturally not come down 2. There are two sensors in the inner box, check whether the wet cloth hanging on the top of the one below is dry, if it is dry, the humidity will be displayed very high, or even 100% 3, check whether the solid-state relay that controls the humidity is broken, etc., this kind of equipment, generally imported will be more mature, Taiwan Temujinke shares**** Before the constant temperature and humidity test chamber was produced, many of our cars and OEMs were using it, and there was no problem.

Let's give you a technology**:。。

Illustrate a picture, I'm worried that you won't find it: 鐧fear of harming the plate of the plate.

That's two different things, the humidity can't go down, it may be that the solid state relay is broken, or the compressor is broken, or it may be leaking refrigerant, many possibilities, to judge from many aspects, as for water leakage, there are many possibilities, one is that the water tank is not sealed, and the other is that the box is leaking.

For example, the door is opened frequently, or there is no ceiling directly, resulting in your environment not having a stable temperature, which has a great impact on humidity; There is also the position of the sensor of your thermostat and humidity machine.

If you don't see the water leaking there, the window that supplies water to the wet cloth is out of water, and the humidity will be 100% and can't go down.

It's too simple to say, and it needs to be detailed; If there is a water leak, how much can't the humidity be set down? How to tell you otherwise.

Based on your literal information, it can be roughly analyzed that it is caused by abnormal control of the control system, and the reasons may be as follows:

1. The PID control parameters of the instrument are improper, resulting in the measured value (PV) fluctuating up or down the target value (also known as the set value SV), which is often said to be too high or too low; The humidity we often talk about is relative humidity, and its value is affected by the ambient temperature, and in the case of abnormal temperature control, the displayed humidity value must seem uncontrollable; In fact, it is not, for example, the target temperature is 50 degrees, 75%RH, at this time, the temperature is too high due to abnormal instrument control, assuming 52 degrees, the humidity value is stable at this time, in the user's opinion, the humidity is not controlled, in fact, it is only because the temperature is high and the relative humidity value drops, and the absolute humidity in the cabin (all are the same. Conversely, if the temperature is too low, the humidity will rise.

2. The parameters of the control instrument are abnormal, and the humidification system is not humidified; The reason is generally that the PID parameters of the meter are incorrect, the heating pipe of the humidifier is damaged, and the humidifier is protected from water shortage.

3. If the temperature or humidity has been rising uncontrolled, it may be the corresponding control solid state relay breakdown.

Other unfinished matters can be inquired at any time.

For the constant temperature and humidity test chamber, the control of temperature and humidity is very related, or it is controlled together, generally when the temperature is 25 85, the humidity can be controlled at 20 98%, if the temperature is higher than 85 or lower than 20, the humidity can not be controlled, at this time, if the customer requires that it must be controlled, it is necessary to use other conditions, by increasing the pressure.

The general constant temperature and humidity test chamber temperature and humidity control is basically together, most of them use the temperature to adjust the corresponding humidity, so in the case of too high or too low temperature, the humidity may not be able to adjust the control.

Of course, there are special circumstances, some customers require more accurate parameters, or low temperature and low humidity, high temperature and high humidity and other special requirements, we will add some other ways to control, such as adding dehumidifiers or humidifiers.

In addition, when the temperature is too high or too low, the humidity cannot be adjusted, such as below 0 degrees, the water will turn into ice, and there is basically no way to control the humidity with any device.

Reasons: 1. Because the temperature cannot be maintained, observe whether the refrigeration compressor can be started during the operation of the test chamber, and the compressor can be started during the operation of the environmental test equipment, indicating that the electrical wiring from the main power supply to the compressor is normal, and there is no problem with the electrical system.

2. There is no problem with the electrical system, continue to check the refrigeration system. Firstly, check that the exhaust and suction pressures of the low-temperature (R23) compressors of the two groups of refrigeration units are lower than the normal values, and the suction pressure is in a state of evacuation, indicating that the refrigeration dose of the main refrigeration unit is insufficient.

3. Touch the exhaust and suction pipes of the R23 compressor of the main engine group with your hands, 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 shows that the (R23) refrigerant of the main engine group is lacking.