Home Appliance Repair-Three common electric kettles (electric boiling water heaters) circuit analysis and fault maintenance
In the figure below, the circuit is composed of the circuit, the control switch, the temperature control switch, the indicator light, and the current limit resistance.
1. Circuit analysis
Dial the switch K1 to the self -control position, and the power switch K is closed after being stamped. At this time, the contact input of the 220V electricity passage K, the first road is powered by the red power indicator of the red power indicator, the second road passes the K1 through the K1 Enter the pot circuit with the power supply terminal, and use the temperature control switch to power the heater. The third road is limited to the green indicator light through the R3. When the water is controlled, the contact switch is disconnected, the heating circuit is cut off, heating, and entering the preservation state. With the extension of the thermal insulation time, after a certain degree of the water temperature decrease band, the contact switch’s contacts are absorbed again, and the heater is heated again, so as to achieve the insulation function.
Dial the switch K to the manual position. At this time, the city’s electricity does not need to pass the temperature control switch and directly power the EH. Therefore, when the water is used, the water should be disconnected in time to prevent the water from burning.
2. Common fault maintenance
No heating, the power indicator is not on
It is due to the opening of the switch K or power supply line. Check whether the power cord and the power socket are normal. If it is not normal, it is maintained or replaced. If it is normal, check the power switch K.
Do not heated manual and automatic, the power indicator lights on
Possible reasons: The switch is abnormal, and the power supply terminal is abnormal, three: the heater abnormal. If there is electricity at both ends of the heater, it means that the heater is turned on. If there is no electricity, use a multimeter to measure the K1 and the power supply terminal.
Normal manual heating, automatic without heating
Temperature control switch, function switch K1 or wiring abnormalities. Use a multimeter to measure these components.
Low heating temperature
Possible reasons: The temperature control switch is abnormal, the second: the heater is abnormal. If the manual heating is normal, it means that the temperature control switch is abnormal. If the manual switch is abnormal, check whether the heater increases the resistance value, and the contact of the contact of the K or K1 of the switching K or K1 will also produce this abnormality.
The figure below is a split fast electric kettle. Such kettles are composed of two parts: pot body and base, of which the base is powered by the pot body; see the figure below
This circuit consists of the thermostat ST1, ST2, heater EH1, EH2, overheating fuse FU1, indicator light, etc. See below.
1. Boil water and heat preservation circuit
When the pot body is placed on the base, the lift protection on the base is replaced by it, and the contacts of L, N, ST1, and ST2 are turned on, so the city electricity enters the pot circuit. When the water temperature is low, the thermostat ST1, the ST2 contacts are connected, and the city electricity and voltage melt fractor FU1, ST1, ST2 input, use D1, D2 semi -wave rectification, through R1, R2, and the luminous pipe LED1. LED2 power supply, allowing them to light up at the same time, and supply power to the heater EH1, EH2, and start heating. After the water temperature exceeds the temperature set by the temperature controller ST2, the ST2 is disconnected to stop the EH2 stop heating. LED2 is extinguished. At this time Continue heating. When the water temperature reaches the temperature set by ST1, ST1 is disconnected, EH1 stops heating, and LED1 is extinguished. Enter the heat preservation state. When the water temperature drops to the closed temperature of ST2, the ST2 contacts are turned on, EH2 begins to heat, LED2 shines, the water temperature exceeds the temperature set by the temperature controller ST2, the ST2 is disconnected, the EH2 stops heating, LED2 extinguishes extinguisons , So under the control of ST2 to achieve thermal insulation function.
2. Overheating protection circuit
When the thermostat ST1, the ST2 abnormality causes the heater to heal too long, which causes the heating temperature to reaches the FU1 melting value, cut off the electricity input circuit, and achieve power outage protection.
3. Common fault maintenance
No heating, the indicator light is not on
If the indicator is not on, it means that the power supply line and the temperature fuse FU1 open the road. First of all, check whether the power cord and the power socket are normal. If it is not normal, it is maintained or replaced. If it is normal, it means that the internal circuit is abnormal. Use a multimeter to check whether the FU1 is opened. If FU1 opens the road. Check whether the contact of ST1, whether the contact of the ST2 is adhesive and whether the heater breaks through.
The indicator light is bright, EH1 is not heated
Check the heater EH1 and its wiring. Whether the multimeter AC voltage test EH1 is about 220V in the city’s electric voltage input. If so, it means that the EH1 is opened. If there is no, it means that the power supply line is abnormal.
The main reason is that the thermostat ST1 is abnormal, resulting in insufficient heating of EH1, only heated by EH2, so the failure occurs. As long as the power supply of EH1 is measured, it can be confirmed whether EH1 is damaged, or ST1 damage.
Can’t keep warm
Explain that the temperature controller ST2 or heater EH2 is abnormal. The measurement of the EH2 has a power supply voltage of about 220V, indicating that the EH2 is opened. If there is no power supply, check the ST2 and the line.
See the figure below, the circuit is composed of the water level switch S1, S2, the temperature controller ST1, ST2 heater EH1, EH2, EH3, EH4, AC contactor KM1, relay KM2, indicator LED1-LED3, etc.
The water level switch, heater and water tank structure below below.
1. Heating circuit
The heating circuit is composed of the heater EH1-EH3, the water level switch S1/S2, and the AC contactor KM1. When the water level of the cold water tank meets the requirements, the water level switch S is turned on, and when the water level in the water tank is low, the movement of the water level switch S1 is connected to the 01 ends. All the way to power the coil of the AC contactor KM1, so that the 3-way contacts of the KM1 are closed, the power supply circuit of the heater EH1-EH3 is connected, and the water vapor is generated after the water is boiled. The box increases the water level. When the water level of the water tank meets the requirements, the S1 moves, its movement contacts at 02 points, cut off the KM1 power supply circuit, the heater EH1-EH3 stops heating and enters the insulation state.
2. When the water temperature is lower than 90 degrees, the temperature controller ST2 is connected. At this time After that, ST2 is disconnected, so ST2 control achieves insulation.
3. Boiling circuit
The boiling circuit is the switch SA, the heater EH4, and the relay KM2 composition. When you need to boil again, press the switch SA, the municipal power voltage passes through SA, the thermostat ST1 is powered by KM2, KM2 is turned on, and power is powered by EH4. The water in the water tank is over 95 degrees. , Stop heating.
4. Common fault maintenance
No heating, the indicator light LED1 is not bright
Check the power supply line, the knife gate QS, and the voltage of the QS line and the end -end voltage can be confirmed whether QS is abnormal, or the line is abnormal.
No heating, LED1 bright, LED2 is not bright
Check the power supply line, measure the resistance values of S1 and S2, and see if they open the way.
No heating, LED2 bright
AC contactor KM1 is abnormal, check the KM1 coil to confirm whether there is power supply, power supply, KM1 abnormal, no power supply, abnormal power supply line
The heater EH1-EH3 or its power supply circuit is abnormal. The resistance value of the heater can determine whether it opens, and it can also measure whether the heater is powered by power supply.
The heater EH4 or its power supply line is abnormal. First look at the indicator light LED3
Whether it glows, no light, check the water level switch S1 and power supply lines, glowing, test whether there is power supply, power supply, EH4 abnormal, no power supply, check KM2.
Heat after boiling
The first is to check whether the S1 of the water level switch is abnormal, and the other is to check whether the thermostat ST1 or ST2 is abnormal. See if the indicator LED2 is always glowing. If so, check S1, if not, check ST1 or ST2.
Low heating temperature
Low heating temperature
Can’t keep warm