Replacing the pressure switch in the dishwasher

If the dishwasher does not start working as usual, then do not close your eyes to it. Any breakdown should not be ignored, even if it is at first glance something frivolous, after some time it can lead to costly repairs to the dishwasher. Therefore, we will talk about what to do if the pressure switch does not work, and how to understand that the water level sensor has broken and needs to be replaced.

Pressostat: varieties and principle of operation

The device of the dishwasher resembles the device of a washing machine, and therefore it also has a built-in water level sensor, the second name of which is a pressure switch. The main task that the pressure switch performs in the dishwasher is to monitor the water level in its tank, while the sensor does not come into contact with water. To determine how much water has entered the tank, the pressure switch uses air pressure.

When collecting water in a dishwasher, the air pressure in the hose or in a special tank rises. This pressure is transmitted through a tube to a pressure switch, inside of which there is a rubber membrane. The membrane expands under pressure and activates switches that are configured for different air pressures, which corresponds to different amounts of water in the dishwasher.

The pressure switch can have a different device: mechanical and electronic. The mechanical water level sensor has a relay and a switch in its device; instead of a relay, an electronic board is installed in the electronic sensor. Both sensors must be replaced if broken.

Note! In dishwashers with a running heater, instead of a water level sensor, a blade type flow meter is installed.

Signs of damage to the water level sensor

How to understand that a water level sensor has broken in a dishwasher? To do this, carefully monitor the water that enters the dishwasher chamber. Symptoms may include the following:

• if there is too much water in the car chamber or vice versa;
• if water does not collect at all;
• too much water is poured, and it begins to merge;
• the machine stopped during operation, water is not pumped out.

The causes of failure and malfunctions of the water level sensor can be:

• sensor wear over a long life;
• oxidation of the sensor contacts;
• defect of the pressure switch elements, for example, a puncture in the tube, as a result of which air escapes, and the pressure does not reach the desired value, the pressure switch does not work;
• clogged pressure tube. Since the pressure in it is very small, then Even detergent can get into the tube, not to mention food debris.

Conclusion! If there is no pressure in the hydraulic circuit for one of the reasons described above, the dishwasher will not work.

Check and replace algorithm

Before changing the pressure switch itself, it is worth checking for performance. To do this, provide access to the sensor. In most models of dishwashers, including Bosch, Electrolux and Ariston, it is located at the bottom of the dishwasher. We do the following:

1. disconnect the car from the water supply, sewage and electrical network;
2. turn the dishwasher sideways or upside down, for this, prepare a place, cover it with a rag so that the rest of the water does not fall on the floor.
3. if your model of a dishwasher Ariston or Electrolux has a cover on the bottom, then remove it, you may need to unscrew the back panel;
4. now find the pressure switch from which the tube goes to the pressure reservoir (a small plastic box) secured to two bolts;
5. Using pliers, carefully pick up the tube from the tank. And then dismantle the pressure tank itself and check for blockages;
6. To check if the sensor is working, you need to blow into the handset and listen. If there is a click, then the sensor is OK, otherwise not;
   

   Important! Since water is constantly moving, the air pressure on the membrane of the pressure switch is constantly changing, which means that it would have worked very often. To avoid this, we set the delay for a couple of seconds, so after blowing into the handset, wait a bit.

7. to check the electrical component of the sensor, a multimeter is required, if a smooth decrease in resistance to zero is observed, then this means that everything is working;
8. if a malfunction is detected, we change the sensor to a new original one, there is no point in repairing it. In dishwashers of different brands Ariston, Bosch, Mile or other pressostats may differ, buy only suitable spare parts;
9. to replace, disconnect all sensors, pressure tube and connect a new unit. Assemble the dishwasher.

So, changing the level sensor in the dishwasher will not be difficult if you know the device of the machine. If in doubt about your abilities, contact a service center for assistance. Together with a sensor, it is sometimes required replace the dishwasher pump, You can also do it yourself, although repairs will cost more.