Fault analysis and maintenance of washing machine

洗衣機壞了。我相信許多人在選擇維修時會感到擔心。讓我們看一下如何自己修復它。

Analysis and maintenance: the circuit of the washing machine is shown in Figure 1. According to the analysis of the fault phenomenon, there may be a problem with the power supply circuit of the washing machine. When the AC 220 V power supply is turned on, the power of the terminal board is turned on. At this time, close the door of the washing machine, and the door switch (electronic lock) is turned on. Press the power switch button, the power indicator light should be on, and the main circuit of the washing machine is turned on.

The indicator light is directly connected to both ends of the power supply through the power switch and the door switch. Now the power on indicator light is not on, and the whole machine has no response. The cause of the failure should be the problem of the power switch or the door switch. After the power is cut off, the power switch and the door switch are detected with the rx1 gear of the multimeter. It is found that the contacts 1-2 and 3-4 of the power switch are not connected, indicating that the power switch has been damaged. After replacing the power switch of the same specification, the washing machine works normally and the fault is eliminated.

Handyman repairs a washing machine

Example 2: turn on the power, turn on the tap, the washing machine can't enter water.

Analysis and maintenance: the washing machine can not water, the fault may be caused by water circuit problems. The working principle of the water inlet circuit is as follows:

When the high water level is selected, the energy-saving switch is not pressed, the contacts 4-6 and 3-5 of the energy-saving switch are connected, the water inlet circuit is 21-22 → 4-6 → 21-1, the water inlet valve, the drainage pump and 18, and the electric opening of the water inlet valve is realized.

When the low water level is selected, press the energy-saving switch, the contacts 4-6 and 3-5 of the energy-saving switch are disconnected, 4-2 is connected, the water inlet circuit is 21-22 → 4-2 → 11-12 → 21-1 → water inlet valve → drainage pump → 18, and the water inlet valve is electrically opened to realize water inlet.

When the washing machine is in the process of water intake, it first has the function of pre water intake: 21-22 → 4-6 → 03 - 23 → 45 → 43 → inlet valve → drainage pump → 18. The action of contact 45-43 is on for 30s and off for 30s, so the washing machine will enter water for 30s and stop water for 30s in advance, intermittently.

When the washing machine enters the rinsing process, in order to improve the rinsing effect, it is also equipped with a strong water inlet function. The water inlet circuit is: 3-23 → x45-43 → water inlet valve → drainage pump → 18. Since the action of the programmable controller contact 45-43 is on for 30s and off for 30s, the forced water inflow is intermittent.

During the maintenance, the main parts of the water inlet circuit, such as the programmable controller, water level switch, energy-saving switch, water inlet valve and drainage pump, were inspected respectively. It was found that the coil resistance of the water inlet valve was infinite, which should be about 4.3K Ω in normal condition, indicating that the coil was broken and could not enter the water. After replacing the water inlet valve, power on the washing machine, the washing machine works normally, troubleshooting.

Example 3: it can not be heated and washed, other functions are normal.

Analysis and maintenance: the washing machine heating washing function is abnormal, the reason may be heating circuit failure. According to the heating and washing principle of drum washing machine, when the heating and washing program is selected, the washing machine program will enter the heating state immediately after the water level of washing machine reaches the predetermined level. At this time, the contact 9-29 of the program controller will be connected, and the contact 5-25 will be disconnected. During heating, the current circuit is: power supply → water level switch contact 21 -24 → programmable controller contact 9-29 → thermostat → unheated switch contact 4-2 → 800W heater → temperature relay → 18.

During the operation of the washing machine, when the water temperature reaches the set temperature (42 ℃), the normally open contact of the temperature controller is closed, and the washing machine begins to wash. At the same time, the heating circuit continues to work, and the washing machine immediately enters the heating washing state until the normally closed contact of the temperature controller (60 ℃) is disconnected, and the heating stops. At this time, the washing machine enters the normal washing process.

During the maintenance, the water level switch, temperature controller, thermostat, heater and other related components were inspected, and it was found that the 800W heater was damaged, resulting in the failure of washing and heating. After replacing the heater of the same specification, the washing machine worked normally and the trouble was eliminated.

Example 4: the water and washing are normal, but the water cannot be drained.

Analysis and maintenance: according to the analysis of the fault phenomenon, there may be a problem with the drainage circuit. According to the working principle of the drum washing machine, we know that: after washing, the drainage pump starts to work, and the current circuit of the drainage pump is: power supply → 22-2 → 10-30 → drainage pump → 18.

During the maintenance, check the program controller contact, drainage pump and other related parts, and find that the drainage pump is damaged, resulting in the failure of drainage function. After replacing the drainage pump, the washing machine was tested, and the drainage work of the washing machine returned to normal.

Example 5: drainage is very slow and other functions are normal.

分析與維護：根據故障現象的分析，洗衣機的電氣系統工作正常，故障原因應為排水管道堵塞。維護經驗表明，滾筒洗衣機的排水管道較差通常是由於排水過濾器中的雜物堵塞所致。另外，排水管彎曲會阻礙排水通道的正常工作，排水泵性能較差。

維護期間，請分別檢查以上項目。首先，檢查排水管，發現沒有問題。然後，檢查並發現排水過濾器的過濾網已被灰塵堵塞。清除污垢後，用水沖洗，並在恢復後將其安裝回本機。排除故障。

例6：洗衣機底部在洗滌時漏水。

分析與維護：根據維護經驗，滾筒洗衣機底部漏水，故障原因如下：

情況7：脫水時，聲音很大，其他功能正常。

分析與維護：洗衣機脫水時會產生很大的噪音。原因是支撐阻尼系統存在問題。