Dishwasher water sensor: types, device, faults + repair

Household dishwashers deservedly received the status of an integral part of kitchen equipment. They really show high work efficiency. But like any other type of household appliances, dishwashers tend to break down from time to time.

A common cause of inoperability is the water sensor in the dishwasher, also referred to as the pressure switch. We will talk about how technical symptoms can determine the fault. We will show you how to fix the damage yourself, and which one is better to contact the service workshop.

Pressostat function in the washer

The peculiarity of the design of the dishwashing machine is the use of the optimal amount of water with high cleaning efficiency.

Actually, this factor is an obvious point, since the degree of cleaning of kitchen utensils dishwashers depend not so much on the amount of water as on its temperature and technology spraying.

In contrast, if the unit uses too much water, due to the increased hydraulic resistance is disrupted by splashing, and heating will require more power and cost. on time.

That is why an important component dishwasher designs is a water level sensor. The presence of this device allows you to monitor and maintain the exact water level in the car.

Meanwhile, correct and flawless operation of the machine is noted, as a rule, in the initial period of operation of the machinery.

Then, at some point in the use of technology, the owner of the dishwasher begins to notice failures in its work. The primary cause of failures usually becomes pressostat. And the point here is not at all in its quality.

The quality of the water used to power the dishwasher plays a significant role in this process. Unfortunately, in most cases of operation, the high quality of water from a centralized water supply system is out of the question.

And low-quality tap water pretty quickly disables plumbing of any kind. Pressure switches washing machines confirmation.

Dishwasher Sensor Types

The level sensors used in the construction of dishwashers can be divided into two groups: mechanical and electronic.

The principle of operation of the pressostat

The device (sensor) of mechanical action works on the principle of transferring water pressure to the silicone membrane. The pressure force from the membrane is transmitted through the rod to the contact device (usually a relay).

The influence of this force mechanically closes or opens the contacts of the control device, which in turn acts on the water supply element.

The cause of the mechanical failure of the system of action, as a rule, is a silicone membrane - more precisely, its physical damage in the form of surface breakdown.

Accordingly, in this state, this element stops working - to perceive pressure. As a result, the user receives a violation of the water level inside the bath of the dishwasher.

Electronic type sensors work in much the same way. Only in this case the relay components are not used. Instead of the relay, mode switching functions (operational, emergency) are performed by semiconductor components.

Electronic devices have additional features - automatic fault detection and display of error messages directly on the machine display.

It is clear that the diagnosis of malfunction in the presence of an electronic device is greatly facilitated. The owner, already by the error code on the display, can first understand for himself what needs to be done in terms of repair.

However, repairing electronic systems is more difficult than mechanical ones. Therefore, with their own hands most likely not enough. Professional intervention is required.

The design of the element

The design of the sensor allows the most unusual scheme. For example, in some famous brand cars Electrolux the pressostat module is made on the basis of two individual sensors.

One of a pair of such devices controls low water level, and the other, respectively, high. Therefore, it is not always possible to get by with simplified dismantling during repairs.

And in another case - when, for example, on the budget brand models Bosch there is only one sensor that monitors the overall water level. In this embodiment, the disassembly is accompanied by less difficulty, but there are difficulties with access to it on the chassis of the machine.

That is why it is not always possible to replace faulty sensors on your own. Often requires the involvement of the master from the profile service workshop.

Meanwhile, in the dishwasher from Electrolux, where two sensors are involved, the device monitoring the high level is used as a backup control element.

If during the operation of the apparatus, the low level sensor does not work, then when the water reaches the upper limit, the drainage pump is turned on. The signal for this is supplied by the upper control device.

The main function of tracking the volume of water is assigned to the sensor, designed to monitor the lower level. This device is activated at the initial stage, when the process of filling the dishwasher with working fluid starts.

Nuances of checking the health of the sensor

The sensor switch is connected to the device itself and as soon as the tank, called the bath, is filled the set lower limit, the pressostat's membrane under pressure acts on the rod moving the contacts switch.

If there is a possible malfunction at this point, you can make sure exactly by checking the low level relay.

For this, the following actions are performed:

1. Removed food dishwasher.
2. The service panel of the control module is opened.
3. The scheme determines the conductors of the relay.
4. The device measures the resistance between them.
5. Without water in the machine tray, the tester should not indicate contact.
6. If there is a contact with filled water, then the relay is working properly.

In the same way, the serviceability of the upper level control relay is checked. Testing is also carried out through the control panel using the concept of the machine.

Identify the conductors and contact plaques on the board coming from the switch of the top-level relay and ring them with an empty and filled pan.

Replacement briefing

Repair as such for pressostat membranes seems to be useless, practically impracticable. As a rule, such elements of the device are subject to replacement.

But before changing the membrane, it is necessary to determine the exact model of the level sensor used. For the dishwasher of every single brand, these details differ significantly.

That is, in any case, the user or service representative will need to disassemble the dishwasher in order to be able to get to the defective part and determine its brand. We will understand how to perform this operation, if it is decided to do the work yourself.

Again, with respect to a particular model of dishwashing technology, the sequence of disassembly may differ.

Consider as an example the Bosch dishwasher variant, in which the mechanical design of the level sensor is used:

1. Disconnect the device from the network and plumbing communications.
2. Prepare a free area for work.
3. On the prepared site, set the machine upside down.
4. Unscrew the screws holding the bottom case cover.
5. Remove the cover and find the pressure switch according to the documentation scheme.
6. To dismantle the device, having previously disconnected all the components from it.

After dismantling the sensor, free access to the relay elements and mechanical parts will open. To check and, if necessary, replace the membrane, you will need to disassemble the pressostat housing. Usually, the two halves of the body are fastened with two or three screws, but more often there are structures on plastic latches.

You should also check the operation of the relay elements. Bosch dishwashing machines usually have limit switches. Check their integrity is easy.

To do this, use the measuring device, which is connected alternately to the terminals of the switch and manually act on the button mechanism. During normal operation of the switch, one of the terminal groups should be short-circuited.

If there is no short circuit, and a characteristic click is not heard, most likely the switch is faulty. In this case, this part must be replaced. You should also resort to replace if there is an unstable (unstable) contact between the terminals.

Useful Repair Tips

Each model of the dishwasher has its own characteristics. Therefore, if the decision is made to disassemble by hand, it is recommended to fix the sequence of actions, for example, by writing on a sheet of paper. Before work, it is advisable to carefully study the instructions and read dishwasher devicein your passport.

All dismantled parts must be laid out in strict sequence of removal; for screws it is better to prepare some kind of small dish or box. If you follow these rules in the process of disassembling / assembling unnecessary problems can be avoided. Yes, and assembly after replacing parts with this solution is much easier to perform.

Assembly is performed strictly in reverse order. Needs attentiveness and ease of action. Many parts of household appliances are often attached with plastic clips, which are easily broken off during a rough installation. After assembly is completed, check the dishwasher for operability.

So that the favorite unit of household appliances does not create problems and does not cause headaches, first of all, you should follow dishwasher operating rules. In this case, the working life of important technical parts and components will increase significantly, and the owners will not need to look for parts for replacement.

Conclusions and useful video on the topic

Video material close to the topic, where the author in an intelligible form tells and shows almost everything that knows about pressure switches - water level sensors used in dishwashing constructions units:

Video about how to repair the dishwasher with your own hands:

After reviewing the sensor device and the order of work when it fails, you can try to repair it yourself. But almost all modern equipment is produced without taking into account the possible repair and more often the broken part has to be completely changed.

Often repairs costing costs that are comparable to the price of a new similar model. Therefore, a more reasonable option is to ensure proper operating conditions for the machine, which will eventually lead to long-term trouble-free operation.

Want to talk about how to pick up the water sensor to replace the dishwasher? Do you have useful information on the topic of the article? Please write comments in the box below, ask questions, share photos and useful information.