Application of liquid level sensor in domestic water heater

- Dec 12, 2019-

The water level sensor is very important for the water heater. Among the water heater failures we have encountered, the failure rate caused by the water level sensor accounts for 50%, so its importance can be seen. In electric water heaters, the main role of the liquid level sensor is to monitor the water level. The sensor is usually located somewhere in the lower part of the water tank, that is, at the preset low water level line. When the water level drops to this point, the output of the liquid level sensor will change, which will trigger the alarm system of the water heater and cut off the power of the heating circuit, protecting the water heater from being damaged by dry burning. In addition to the liquid level sensor, a temperature controller is also installed in the water heater to accurately measure the change in water temperature, set the heating time reasonably, and avoid waste of electricity. However, the liquid level sensor and the temperature sensor determine the quality of the water heater to a certain extent. Their function is to measure the water temperature and level of the water heater and then transmit it to the controller, which plays a protective role in the intelligent control of the water heater. At present, most water heater products are equipped with liquid level sensors and temperature sensors, but due to scale effects, high temperature problems, interference problems, environmental effects and other problems, it is difficult for the sensor to work normally for a long time. So what kind of liquid level sensor is good for water heaters? What is the principle?

The photoelectric liquid level sensor is a new type of contact point liquid level measurement and control device developed using the principle of reflection and refraction at the interface between two different media. It has simple structure, high positioning accuracy, no mechanical parts, no commissioning, high sensitivity and corrosion resistance, low power consumption, small size and many other advantages and has been gradually recognized by the market.


1. Because the output of the liquid level is only related to whether the photoelectric probe is in contact with the liquid surface and has nothing to do with other characteristics of the medium, such as temperature, pressure, density, electricity and other parameters, the photoelectric liquid level sensor detects accurately and has high repeatability; fast response. The liquid level control is very accurate and can be directly installed and used without adjustment.

2. Due to the relatively small size of the photoelectric liquid level sensor probe, it can be separately installed in a narrow space and suitable for use in a special tank or container. In addition, multiple photoelectric probes can be installed on a measuring body to make a multi-point liquid level sensor and a variable controller.

3. As all the components inside the sensor are resin-sealed, there are no mechanical moving parts inside the sensor, so the photoelectric liquid level sensor has high reliability, long life and maintenance-free.

The low-cost infrared liquid level sensor provided by EPTSensor. The sensor is specially designed for high-volume OEM customers. The sensor contains an infrared emission source and a detector. When the tapered end of the sensor is immersed in liquid, infrared light will be transmitted out of the tapered surface, and the intensity of the light reaching the detector will be weakened. Therefore, the low-cost photoelectric liquid level sensor is widely used in hot spring pools, leak detection, vending machines, food and beverage machines, medical, compressors, printers, water pumps, home appliances, oil level monitoring, HVAC, machine tools, High and low level switches, water level control, automotive electronics and other fields.