What will happen if tap water is used in a Temperature Humidity Test Chamber? Author：LINPIN Update Time：2025-03-31 Source：LINPIN The Temperature Humidity Test Chamber is a familiar piece of equipment to many. During training or in the user manual, it is always emphasized that the water used in the chamber must be deionized water, purified water, or distilled water, rather than tap water. But why is this the case? Below are the reasons: If tap water is used instead of deionized or distilled water in the constant temperature and humidity chamber, the following consequences may occur: The heating elements and the inner walls of the boiler used for humidification will develop scale. Over time, the scale on the heating elements will prevent the heat from being dissipated properly, which can easily cause the heating elements to burn out. Tap water, after being transported through pipes to the user, may have an improper pH level. This can lead to corrosion of the metal parts in the equipment that come into contact with the water, especially at welded joints. Over time, these corroded areas can become weak and eventually rust through, causing leaks. The wick on the humidity sensor is also in direct contact with the water. The upper end of the wick is exposed to the humid environment inside the chamber, while the lower end is immersed in the water tank containing tap water. If the humidity test is conducted frequently, the wick will become hard and yellow, and it will accumulate scale. This reduces the wick's water absorption capacity, thereby affecting the accuracy of humidity measurement. Therefore, the wick needs to be replaced every month. When tap water is used for humidification, the large amount of water vapor inside the chamber will condense on the surface of the test samples. For some components of the samples, this can cause damage due to the tap water vapor. The water droplets produced by tap water humidification are relatively large. When conducting long-term humidity tests, this can affect the lifespan of the humidity sensors. Currently, there are two main types of humidity sensors: capacitive sensors and electronic humidity sensors. The electronic humidity sensors, which are exposed inside the chamber, have PCB boards that are not coated with waterproof or anti-oxidation materials. If the tap water quality is poor, it can cause short circuits in the humidity sensors during humidity measurement. The stainless steel humidification boiler in the constant temperature and humidity chamber is usually equipped with a water level float switch. The float in the switch contains a magnetic rod, and it is not made of anti-oxidation material. If humidity tests are conducted frequently or if the water is not changed regularly, the water level float switch can short circuit.
