Preheating bath water tank water level controller

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Preheating bath water tank water level controller [Copy link]

This circuit has a simple structure, easy materials, reliable performance and convenient operation.

Working principle: Assuming that there is no water in the water tank and water needs to be preheated, as long as K1 is closed (see the figure below), the green indicator light will be on, and the solenoid valve will be energized through the normally closed contact of J1-2 to open the valve to let water in. When the water in the water tank rises to plane S1, the compound tube composed of BG1 and BG2 will be forward biased and drive the relay J1 to operate and pull J1-1. At the same time, J1-2 will operate, the solenoid valve will be powered off and the water will be turned off. The AC contactor J2 will be powered and pulled in. The electric heating tube R1 will heat the water and the red indicator light will be on. During the bathing process, the water level continues to drop. When the water level is lower than plane S2, the compound tube loses the forward bias and releases J1. The solenoid valve is powered on again to open the valve to let water in. The electric heating tube loses power and is protected, and the red indicator light goes out.

Sometimes it is necessary to position the water surface between plane S1 and plane S2. When the water level reaches this plane, press K2 once to complete the above function. When the water surface has been positioned between plane S1 and plane S2 and the water level needs to be raised, just press K1 twice. When the water temperature reaches the requirement, K1 can be disconnected to stop the machine. However, the temperature of the bath water is generally adjusted by the water outlet valve of the water tank and the tap water valve, so the water temperature in the water tank is not controlled by the circuit.

Component selection: K1 and K2 are ordinary pull-wire switches and doorbell buttons respectively. The AC contactor, fuse, and electric heating tube are selected according to the power used. The two water level detection rods are preferably made of stainless steel. You can also remove the 5 cm sheath of the copper core plastic wire at the head end and replace it. J1 is a JQX-4 type relay with two contacts and a voltage of 12V. When manufacturing the water tank, it is best to have a glass tube water level display, and it is required to wrap the box body with asbestos material to play a role in heat preservation. If you do not use a solenoid valve, you can merge the right figure into the left figure to make a full water alarm. Just connect A, B, and C in the right figure to the corresponding A', B', and C' (not found).

lorant

I don’t really understand it, but it’s very useful.