How to check the lock of an Indesit washing machine?

How to check the lock of an Indesit washing machine The door of each “frontal” is equipped with a UBL, which blocks the hatch from accidental opening during washing. Without electronic locking, the drum can easily open, causing a flood, short circuit, or worse. But if the cycle has ended, and the washing machine is still locked and does not respond to user commands, you need to check the lock of the Indesit washing machine. There is probably a system failure, blockage, wear or other breakdown of the blocker.

Sensor design features

Before you begin diagnosing and repairing the lock, it is worth understanding its mechanism and operating principle. Here a lot depends on the type of blocker. Thus, the old Indesit models were equipped with electromagnetic locks, which did not require special repairs. The fact is that the “magnets” are immediately unblocked when the power is turned off, so they are ineffective in operation and are not currently used in the production of washing machines.

Modern Indesit machines have a different type of lock - bimetallic. Unlike its predecessor, this lock is more reliable and will not allow the door to be opened during washing. But it is also more difficult to fix. The improved UBL consists of the following elements:

thermocouple;
bimetallic plate;
retainer

Modern Indesit machines are equipped with a lock with bimetallic plates and a thermoelement.

The device works like this: the control board sends a current signal to the thermoelement, which heats up in a matter of seconds and conducts the charge further - to the plate. Due to the bimetallic base, the part increases in size and puts pressure on the latch. It falls out and clings to the ledge in a special groove.Everything happens very quickly, and the final operation of the UBL is indicated by a characteristic click. If it sounds, then the machine is closed and ready to fill the drum.

The door opens in the same way, but in the reverse order: when the current supply stops, the plate decreases, the latch returns to the specified place and the lock is removed. There may be a slight delay, since the Indesit safety system often holds the lock until it is sure that the tank is empty. You should wait a few minutes and press the hatch handle again. UBL design

If the door still does not budge, it means that there are problems with the operation of the UBL. We will discuss the causes, consequences, symptoms and necessary repairs in case of faulty locking below.

Why does the lock break?

An electronic lock breaks down mainly for two reasons. The first is wear and tear due to long use. In more detail, when heated, the bimetallic plate gradually deteriorates and collapses, which leads to weakening of the fixation to a minimum. In this case, repair will not help; it is better to dismantle the old device and install a new analogue. Why does the lock fail?

Problems with the electronics of the washing machine also lead to a faulty lock. There are two options here:

power surges in the network “pierce” the thermoelement, which stops heating and starts a chain reaction on the plate and retainer;
The triac responsible for the UBL on the control board closes, the current supply to the blocker does not stop, and the locking is not removed.

The UBL fails due to wear or problems with the electronics of the washing machine.

In addition to electronic problems, mechanical reasons also lead to door blocking. So, the hatch will not budge if there is sagging, deformation of the door hinges or a broken tongue on the lock itself. Therefore, it is forbidden to hang wet things on the door and allow children to “ride” on it. To accurately determine the nature and extent of the breakdown, it is necessary to carry out appropriate diagnostics. Then it will be easier to troubleshoot and continue the planned wash.

Multimeter Test Procedure

As a rule, if there are problems with the door lock of the machine, it is easy to guess that the UBL has failed. With such a “diagnosis,” the machine clearly makes it clear about the nature of the breakdown. So, the following “symptoms” occur:

the hatch does not open, although several hours have passed since the end of the cycle;
error code F17 appears on the screen or the Start/Stop button on the dashboard flashes 17 times;
the door does not budge, even when the machine is disconnected from the power supply;
When I try to start the cycle, the lock does not work and the wash does not start.

If at least one sign from the list is present, then there is a problem with the operation of the UBL. Most often, the device itself, the wiring connected to it, or the control board of the washer leads to breakdown. A check with a multimeter will allow you to more accurately determine the cause.

Before starting diagnostics, we study the electronic circuit of the existing washing machine. It is important to find out where the “neutral”, common contact, and “phase” are located. Afterwards, you need to remove the UBL itself from the machine. We act like this.

We disconnect the washing machine from the supplied communications.
We open the door.
Unscrew the bolts holding the UBL.
Unscrew the two bolts from the back that secure the top cover of the machine.
Push the lid away from you until the latches engage and remove it.
We run the hand down towards the UBL (to the right of the cuff).
We unhook the wiring connected to the UBL and, holding it with the other hand, take out the device.

Next, take a multimeter, turn on the “Resistance” mode and apply the probes to “neutral” and “phase”. If a three-digit number is displayed on the display, then we proceed to the second stage; if it is less, we immediately change the UBL to a new one. The next step is to connect the “empty” wire to the common contact, and the second to the “phase”. Using a screwdriver, move the latch on the blocker to the working position and connect to the power supply. A working device will click, but a broken one will not.

We determine the breakdown without disassembling the machine

It is not necessary to disassemble the machine to verify that the UBL is faulty. Sometimes you can diagnose a breakdown of the blocker remotely - by the behavior of the washing machine itself. The main thing is to know the structure of the machine and the operating principle of its components. As a rule, a damaged electronic lock reveals itself with several “symptoms”.

If the washer hatch remains locked for several hours after disconnecting the machine from the power supply, then the UBL is faulty.
If, when starting the cycle, an error code is displayed on the display indicating problems with the UBL (for most Indesit models, the combination “F17” signals a faulty lock).
If after selecting a program the machine does not lock the door. In this case, either the electronic lock or the control board is broken. The multimeter test described above will help determine the “culprit.”

! If there are problems with the UBL, the self-diagnosis system of Indesit machines displays the error code “F17”.

Thanks to UBL, the machine has double protection, which will prevent a person from opening the door when the tank is full. If the lock is “buggy” and cannot be removed or installed, then it is necessary to urgently diagnose and fix the problem.