Bosch dishwashers are considered to be reliable appliances, but even they can fail occasionally. The most common malfunction in Bosch dishwashers is of the heating element, so we will consider how to diagnose and repair this fault.
How to diagnose the failure
Bosch advanced dishwashers come with an electronic self-diagnostic system. If it detects any malfunction, it displays a corresponding alphanumeric code on the dashboard. In some cases, water is heated up, but slowly, and the system cannot detect the fault. In this case, you will have to diagnose your Bosch dishwasher yourself.
The steps are as follows:
- Install the dishwasher in a way so that the bottom panel can be reached.
- Remove the back panel (for freestanding appliances) or the bottom panel (for in-built models). For the successful removal of the panels disconnect the drain branch pipe from the water basin, gently pull the panel toward you, and it easily comes off.
- Using a multimeter, check the temperature sensor, inspect the wiring and contacts for any damaged insulation and melted elements.
- If the sensor inspection indicates that no critical failures were found, you need to check the Bosch dishwasher heating element.
The internal structure of the dishwasher
All the parts and control elements are inside the Bosch dishwasher housing. The main parts of this system are:
- The inlet valve with the intake system controlled by the microcontroller.
- The filter retaining small pieces of food and other debris.
- The drain system consisting of the drain pipe connected to the sewer and the pump. The operating principle is similar to the one in a Bosch washing machine.
- The float switch protecting the dishwashers from various leaks. When this cylindrical plastic container floats, it closes the circuit. This happens in case of an excessive water intake.
The types of heaters
The main challenge for the Bosch dishwasher heating element is frequent overheating. This phenomenon is caused by the constantly increasing layers of scale. The tubular heating element suffers from it, especially if no water softening agents are added while using the appliance.
The types of the Bosch dishwasher heating elements are as follows:
- The immersion type or the so-called “wet” type. Such a heating element has a direct contact with the water and warms it up.
- The sheathed (“dry”) type. The actual heating element has a protective shield on it.
Experts believe dry heaters to be more efficient. Due to no direct contact with the fluid, they can last for a much longer time. The wide bulb contributes to the rapid water heating process and little scale formation.
How to replace the part
The heating element is quite close to other working parts. In order to successfully replace the dishwasher heating element, follow these instructions:
- Open the door and remove the dish rack.
- Disconnect the unit from the mains and disconnect all the hoses.
- Remove the plastic spray arm located at the bottom of the dishwasher.
- Then you can see a plastic cylinder next to it. This is a filter, remove it.
- Remove the steel mesh located below.
- Unscrew the five fasteners fixing the hose and the heater.
- Place the unit on the top panel to provide free access to the bottom part.
- Remove the back panel.
- Remove the pump. Rotate it clockwise, then gently pull the part away. Note: it is enough to make half a turn, avoid sudden movements. Remove the temperature sensor and put the pump aside.
- The heater is attached to the bottom of the dishwasher with some rubber element. It is quite easy to remove.
- Remove the rubber fixture and disconnect the hoses and wiring. Remove the failed heater and replace it with a new one.
Assemble the dishwashing machine in the reverse order. Follow the instructions carefully.
They say the heating element is the heart of the dishwasher, and this statement is not far from the truth. Its critical disorder can cause irreparable damage to the entire appliance, as well as lead to leaks and large troubles. Check its performance, clean up the scale regularly, and replace the part if necessary.