There are three common types of controllers for high and low temperature test chambers: software failures, system failures, and hardware failures.

1. Software failure: Software failure mainly refers to the controller failure of the high and low temperature test chamber, including internal parameters, IS control and output signals of various control points that control the on-off of the solenoid valve.

2. System failure: System failure refers to problems with the initial design of the refrigeration system, including refrigerant leakage that causes the high and low temperature test chamber to not cool down. Refrigerant leakage is often caused by shaking during transportation and operation of the high and low temperature test chamber, or poor welding technology of the refrigeration copper pipe.

3. Hardware failure: There may be hardware compressors, solenoid valves, and other cooling components that do not cool down.

So users can roughly understand what hardware high and low temperature test boxes are damaged by listening and touching. If it is a compressor malfunction, the compressor's sound will be abnormal or will not work or start, or the compressor's own temperature will be much higher than usual. However, electromagnetic valve faults and other cooling component faults are not easy for users to grasp.

In addition, damage to the controller and electronic components that control the refrigeration system may also cause the phenomenon of the high and low temperature test chamber not cooling and not cooling.

The scientific principle of heating and cooling in high and low temperature test chambers:

The high and low temperature test chamber has functions of heating, cooling, humidifying, and dehumidifying, which can detect the product's ability to withstand high temperature, low temperature, and humidity. So how is the temperature controlled in the high and low temperature test chamber.

The heating device is a key link in controlling whether the high and low temperature test chamber heats up. The controller outputs a voltage to the relay when receiving the heating command. The high and low temperature test chamber has approximately 3-12 volts of direct current applied to the solid-state relay, and its AC terminal is equivalent to a wire connected. The contactor also draws in at the same time. There is voltage at both ends of the heater to heat it up. The heat is carried to the chamber through a circulating fan, causing the constant temperature and humidity test chamber to heat up.

Cooling is an important part of a high and low temperature test chamber, which directly affects the judgment of a high and low temperature and its performance. It consists of four major components: a compressor, a condenser, a throttling device, and an evaporator. The compressor is the heart of the refrigeration system, which sucks in low temperature and low pressure gas, turns it into high temperature and high pressure gas, condenses it into a liquid, and releases heat, which is carried away by the fan. Therefore, the reason for the hot air is below the test chamber, Then it becomes a low-pressure liquid through throttling, and then becomes a low-temperature and low-pressure gas through the evaporator before returning to the compressor. The refrigerant absorbs the heat from the high and low temperature boxes in the evaporator to complete the gasification process and absorb the heat, achieving the purpose of refrigeration and completing the cooling process of the high and low temperature test box.

Test program for heating and cooling rate of high and low temperature boxes:

Within the adjustable temperature range of the test chamber, select Zui low nominal temperature as Zui low cooling temperature, and Zui high nominal temperature as Zui high rising temperature.

Turn on the cold source and lower the test chamber from room temperature to a low cooling temperature. After stabilizing for at least 3 hours, raise it to a high heating temperature. After stabilizing for at least 3 hours, lower it to a low cooling temperature. During the heating and cooling periods, record once per minute until the end of the test process.

The principle of heating and cooling in a high and low temperature test chamber is like this. Its function is achieved through the setting of the control system. Understanding the principle of heating and cooling will definitely make it more convenient to use a high and low temperature test chamber.

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