How does a washing machine lock work?

Sometimes users face the fact that the door of the washing machine does not lock, or, on the contrary, does not want to open after washing. In most cases, the reason for this is the blocker. The lock can become clogged with dust, burn out, or simply stop working due to wear. To fix the problem, you will have to delve into the structure of the washing machine UBL. Understanding the principle of the blocker, knowing what parts it consists of, even a beginner will be able to diagnose the lock. Let's look into the nuances.

What types of locking devices are there and how do they work?

Having decided to deal with the problem yourself, you need to have an idea of ​​how the UBL is arranged, what locks are installed on automatic machines. Over the past decades, manufacturers have equipped washing machines with either electromagnetic locks or mechanisms with bimetallic plates.

As for electromagnetic devices, they are considered to be quite unreliable. Such locks block the hatch only when the voltage is supplied. If the power is suddenly turned off in the apartment, the mechanism will immediately stop working. Modern washing machines, in the vast majority of cases, are equipped with UBL based on bimetallic plates.

The principle of operation of blockers with bimetallic plates is very simple. The operation of the mechanism is ensured by three components:

• Thermoelement,
• Hook-fixer,
• Bimetallic plate.

When the user starts washing, voltage is supplied to the UBL heating element. The part heats up and transfers heat to the bimetallic plate. Then the plate, under the influence of high temperatures, increases in size and presses the lock. The hook quickly operates and closes the mechanism, thereby blocking the door. While the current "enters" the lock, the hatch remains tightly closed.

When the wash is finished and the voltage supply is stopped, the heating element gradually cools down. The bimetallic plate stops heating up and decreases in size, pulling the "hook" back. After this, the hatch of the washing machine can be safely opened.

It happens that the contact of the locking device breaks through. In this situation, the heating element remains cold, the plate does not heat up, the lock does not work. The control module does not receive a signal about the tightness of the system, so the wash does not start.

 

The opposite situation is when power is supplied to the locking device continuously, even after the end of the cycle. Then the elements do not cool down, the control module keeps the door locked. In this case, you can only access the drum by disconnecting the power supply to the machine.

Malfunctions indicating UBL

How to understand that the blocking device is faulty? In some cases, you can diagnose the breakdown without even disassembling the "home assistant". The machine itself will indicate the malfunction. You should think about the fact that there are problems with the blocker if:

• The washing machine door remains locked even 2-3 hours after the program has finished,
• After starting the wash cycle, the machine display shows an error code indicating problems with the UBL,
• Attempts to start washing are unsuccessful - the UBL cannot lock the hatch. In this case, the reason may be either in the lock or in the control module.

Having identified even one of the listed "symptoms", it is better to immediately dismantle the locking device and check it. Let's figure out how to remove the lock from the washing machine body.

Dismantling the UBL for inspection

Understanding how the UBL works, it will be easy to check the mechanism for operability at home. The blocker is diagnosed with a multimeter. How to remove the lock from the body of the automatic machine? There are two options. The first is to get the UBL through the front wall, removing the hatch cuff. The second is to pull the device out through the top of the machine, removing the body cover. The latter option is more suitable for beginners, because the sealing rubber is not so easy to put back in place. If you do this task incorrectly, you can easily break the tightness of the system. Then leaks will be guaranteed.

The algorithm of actions will be as follows:

• De-energize the equipment,
• Open the washing machine door all the way,
• Find the keyhole, it is located to the right of the hatch (this is a small “well” where the “tongue” of the door enters),
• Unscrew the two bolts located next to the lock hole,
• Feel the blocker and remove its plug with wires,
• Pull the UBL out.

Now the blocker will be in your hands. No need to buy a new device right away, maybe it is not the problem. Therefore, check the part with a multimeter.

Checking the removed element

First, look in the machine manual and find the UBL electrical diagram there to study the location of the contacts. Once you understand where the neutral and common terminals are, and where the phase is, turn on the multimeter and switch it to the resistance measurement mode. One ohmmeter probe should be applied to the neutral contact of the blocker, the second to the phase. If a three-digit number appears on the device display, it means that the locking device has passed the test.

Next, the probes are applied to the neutral and common contacts of the UBL. Zero or one displayed on the multimeter display will indicate a malfunction of the lock. The blocker cannot be repaired; it will need to be replaced.