Electric heaters are used in the baking, drying and other temperature tests of constant temperature heating samples in various industries. It is an indispensable tool for biology, genetics, medicine and health, environmental protection, biochemical laboratories, analysis rooms, teaching and research. Any equipment has The possibility of failure, in order to make the electric heating plate work better, reduce the number of failures, and increase its work efficiency. The editor of the electric heater manufacturer analyzed the typical faults in detail, introduced the processing process, and summarized the maintenance ideas.
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Fault 1: Turn on the heating switch of the constant temperature heating table, the aluminum platform does not heat:
Reasons: 1. The heating tube is very likely to be broken; 2. The heating switch is broken; 3. The solid state relay is broken; 4. The thermostat is broken.
Inspection and maintenance methods:
Open the bottom cover of the constant temperature platform:
1. Detect the heating tube: first cut off the power of the whole machine, use a multimeter to check the resistance of the heating tube at the ohm level. The wires of the heating tube should be cut off for testing. The resistance of the heating tube is generally dozens of Ohm to about two hundred ohms. If the resistance is infinite or a few ohms, it can be considered that the heating tube is damaged and replace it.
2. Check the heating switch: first cut off the power of the whole machine, turn the multimeter to the buzzer position, turn the switch to the one-digit position, use a test pen to measure whether the terminal of the switch is in the on state, and both terminals are connected to indicate this The switch is good, otherwise it needs to be replaced.
3. Detect the solid state relay: This requires the constant temperature platform to be connected to the power supply, but be careful of electric shock! Then turn on the heating switch to see if the solid state relay indicator light is on or flashing, it can be regarded as the solid state relay input terminal is normal, if it does not light up Use a multimeter to check the 3-4 terminals of the solid state relay to see if there is a 12VDC voltage. If not, the thermostat is damaged. Then turn the multimeter to the 750VAC position and measure the 1-2 terminals of the solid state relay with a test pen. If there is 220VAC voltage and it does not change, then the solid state relay can be regarded as damaged and replaced.
4. Check the thermostat: connect the thermostatic platform to the power supply, turn on the heating switch, and see if the thermostat is displaying normally. If it is displaying normally as usual, set the multimeter to the DC range of 20VDC, and measure the 3-4 terminals of the solid state relay. Check if there is a 12VDC voltage, if not, it can be considered that the thermostat is damaged and replace it.
Fault 2: The temperature of the aluminum platform is high on one side and low on the other side:
One of the heating tubes is damaged, and the heating tube is measured according to the above heating tube inspection.
Fault 3: The digital display of the thermostat jumps randomly:
1. If the number tube code in the SV window has the letter "AT" jumping, it means that the decimal point shift key has been long pressed during operation by mistake, and the auto-tuning of the thermostat has been started. To cancel, please press and hold the decimal point shift key for 3 seconds. Then let go, the jumbled "AT" letter will disappear, if you don't cancel the thermostat, it will automatically cancel within 30 minutes.
2. If the digital tube of the PV window displays 1312 and the digital tube of the SV window displays "ORAL", it means that the temperature sensing line is open and replace it.
This is the fault detection and maintenance summary summarized by the editor of the silicone electric heating film, I hope it will be helpful to everyone.
