Bosch dishwasher valves

valve for PMM Such small and simple parts as valves for a Bosch dishwasher are of great importance for the operation of the device as a whole. If at least one of the valves of the “home assistant” begins to work intermittently, the machine will either not be able to perform its main function at all, or will do so with serious interruptions. In this publication, we list all the types of valves that are installed in Bosch dishwashers, give them a brief description and talk about the features of replacing them. We hope it will be interesting.

Types of valves

The task of any valve in a Bosch dishwasher is to allow a certain amount of liquid to pass in a certain direction, and then to shut off its flow at the right moment. The solenoid valves operate under the guidance of the control module. The latter gives a command, after which the valve either opens or closes. Mechanical valves operate independently, but they provide just as much benefit. What types of valves are there in a Bosch dishwasher?

Solenoid water inlet valve.
Drain check valve.
A special valve that protects the machine from emergency leakage of Aquastop.

Each of these valves has its own device, is installed in a specific location and changes in accordance with a specific algorithm. We will discuss this in detail below.

Inlet

The intake valve has a very important role. It shuts off the water that flows under pressure into the dishwasher. Its main task is to command the control module to open for a while in order to pump a certain amount of water into the machine, and then close again on command.The valve is activated whenever clean water needs to be added to the dishwasher. Depending on the program, this may be required from 2 to 8 times per wash cycle.

fill valve

Malfunctions in the operation of the control module or the wiring connecting the control board to the inlet valve will lead to dysfunction of the latter.

The relationship between the inlet valve and the control module makes it possible to quickly shut off the water not only in normal operating conditions, but also in an emergency. Although in case of an accident the machine has a special valve.

Antisiphon

A non-return or anti-siphon valve is much simpler, but this does not mean that its role is diminished in any way. An anti-siphon valve is installed on the dishwasher drain at the base of the drain hose. As soon as the pump begins to pump waste water into the sewer under pressure, this valve opens and freely allows sewage to flow into the drain. If the pump stops working, the valve closes securely.

drain valve

If sewage suddenly flows from the sewer back into the dishwasher, a reliable anti-siphon valve will block its path. No matter the pressure under which sewage flows from the sewer, the valve will stop it. Some users who installed their own dishwashers ignored this valve and already bitterly regretted it. When a blockage occurred in the drain, all the sewage entered the dishwasher and landed on clean dishes. Sheer unsanitary conditions! In general, you can’t imagine a single Bosch dishwasher without an anti-siphon valve, and now you understand why.

Protects against leaks

The emergency valve is an integral part of the Aquastop system. Some people mistakenly believe that this valve is the only part of the protective system, but this is not the case.Bosch dishwashers with partial leakage protection have a special sensor with a float in the tray. When enough water enters the pan, the float rises and closes the contact of the sensor, which in turn sends a signal to the valve. And it instantly shuts down.

aquastop PMM

In the future, in order for the valve to open again, you will need to open the sensor contacts in the pan by draining the water and eliminating the cause of the leak. The Aquastop valve, installed on the inlet hose of a Bosch machine with complete protection against leaks, is activated when the hose ruptures. The fact is that the Aquastop hoses for such machines are also unusual. They have a double layer.

When the main layer breaks under pressure, water gets between the layers and puts pressure on the valve.
The valve closes tightly, blocking the flow of water into the machine.
No matter how much the user tries to restart the machine, it will not work.

In this case, no measures will help; a complete replacement of the hose is necessary, since this system is designed as a disposable one. The next hose will serve until a similar emergency occurs, fortunately this happens infrequently, otherwise the user would go broke buying new hoses.

Features of replacing these parts

When replacing the fill valve, the main thing is not to mix up the contacts when connecting it, but you will first have to remove the dishwasher tray. More information about disassembling the machine is described in the article. How to fix error E14 in a Bosch dishwasher, we won’t dwell on this now.

The inlet valve is directly connected to the inlet hose, so it will not be difficult to find. Before you dismantle the old valve and remove the wires from it, take a photo of it. Next, use a multimeter to check whether the part is working properly, and only then proceed with replacement.Install the wires in the correct order, and only then assemble the machine.

The anti-siphon valve only needs to be replaced if it is clogged. This usually happens after 5-7 years of using the dishwasher. The old valve must be unscrewed and the new one screwed in, nothing tricky. But this must be done at least once every 7 years, otherwise the clogged valve may not work at a critical moment and you will not like the result.

The Aquastop valve is easier to change than others. This does not even require disassembling the dishwasher, since this valve is located on the outside. The only thing I'm not happy about is its cost. On average, it costs about $45 and during the life of 1 dishwasher (7-12 years) it can fail 2-3 times. Agree, it’s quite expensive, but without it there is a risk of flooding the neighbors below.

In conclusion, we note that there are not many valves in a Bosch dishwasher, but each of them is in its place and plays an important role in the overall performance of the equipment. Thanks largely to these details, we wash a mountain of dirty dishes every day without any physical effort. And this is worth a lot!