Junkers Cerapur 9000i Boiler

This display shows the current operating pressure of the device. A reading of 0.9 BAR indicates that the water pressure in the heating system is low.

The mains voltage supplied to the boiler is below the acceptable operating threshold. This can be a blocking fault.

The boiler detects that its operating pressure is too low, below 0.2 bar. This is a blocking fault, meaning the system may temporarily shut down but could restart automatically once pressure is restored.

The fan (blower) within the boiler is running at a speed that is too high, which can affect combustion and exhaust. This is an interlocking fault.

The coding plug (KIM) installed is either incorrect or not being recognized by the boiler's system. This is an interlocking fault.

This group of codes indicates that the automatic burner or the Coding Identification Module (KIM) is defective. This is a critical interlocking fault that requires a reset after correction and often professional intervention.

During the burner's operation, there is insufficient flame formation (ionization current). This can lead to inefficient heating or shutdowns.

The fan (blower) within the boiler is running too slowly, which can negatively impact combustion and exhaust. This is an interlocking fault.

A temperature limiter, either for the heat block or exhaust gas, has triggered, indicating overheating or an issue with exhaust gases. This is a blocking fault.

An external switching contact, such as for a thermostat or safety device, is detected as open. This can prevent the boiler from operating.

The fan (blower) shows irregular operation during the start-up phase of the boiler. This is an interlocking fault.

During the burner ignition attempt, there is insufficient flame formation (ionization current). This can prevent the boiler from starting.

The ignition device has been active for an excessively long period, which can indicate an issue with ignition or flame detection.

The boiler is not receiving speed feedback from the heater pump. This indicates a communication or functional issue with the pump.

The boiler's blower (fan) has failed. This is a blocking fault that prevents proper combustion and exhaust.

The heating pump is running but is not generating adequate pressure in the system. This indicates a problem with water circulation.

The boiler's control system has detected an incorrect type of pump installed or configured. This is an R-class non-blocking interference.

The device detects an issue potentially related to its software or external electrical interference. This can be a blocking fault.

The domestic hot water (DHW) temperature sensor is defective. This is an R-class non-blocking interference.

The boiler experienced a brief interruption in the mains voltage supply. This can be a blocking fault.

The automatic burner's control unit is reading an incorrect value, which can prevent proper burner operation. This is an interlocking fault.

The attached KIM (Coding Identification Module) does not match the automatic burner, or the burner automat reads an incorrect value. This prevents proper operation.

Communication on the BUS system (internal network) of the boiler is interrupted. This can prevent components from communicating correctly.

The temperature measured by either the flow temperature sensor or the return temperature sensor is rising too quickly. This indicates a problem with heat dissipation or circulation.

The flow temperature sensor has a short circuit, causing incorrect temperature readings. This is a blocking fault.

The flow temperature sensor has an interruption in its circuit, leading to incorrect temperature readings. This is a blocking fault.

The heating pump within the device is not turning or operating as expected. This can be a blocking fault.

The temperature sensor for the storage tank is defective, leading to inaccurate temperature readings. This is an R-class non-blocking interference.

The system detects flame formation (ionization current) even after the burner has been switched off. This indicates that the gas valve might not be closing correctly.

When the boiler displays 'BOILER TEMP. MAX.100%' in chimney sweep mode, it indicates the device is operating at full heating capacity for measurement purposes. Hot water operation is disabled during this mode.

The boiler is producing excessively loud combustion noises or persistent humming sounds during operation.

The cylinder temperature sensor, which monitors the temperature in the hot water cylinder, is faulty or has connectivity issues. This is an R-class non-blocking interference.

The boiler is completely unresponsive and its display is dark, indicating a power supply issue or major internal failure.

This display indicates the boiler is in manual or emergency operation, with the boiler temperature set to 70°C. This mode allows the device to continue running with a set boiler output, typically used for a few days if the control unit is not functioning properly.

The measured exhaust gas values are not within the acceptable range, and the carbon monoxide (CO) content is too high. This is a serious safety concern.

The boiler's display shows 'FAULT PRESENT', indicating a general issue with the device. This could be either a blocking fault, which allows the system to restart automatically after the issue is resolved, or an interlocking fault, which requires a manual reset to restart.

The heating system is producing noticeable flow noises, indicating issues with water circulation or pump settings.

If the heating system is taken out of service for a longer period during cold weather, there is a risk of system damage due to frost. Water in the pipes can freeze and expand.

The heating system is taking an unusually long time to reach the desired temperature, indicating inefficiency or a problem with heat generation/transfer.

The measured flow temperature in the heating system is higher than what is calculated or set. This is a non-blocking interference, meaning the heating system remains in operation but may not perform optimally.

The boiler is unable to reach the desired or set hot water outlet temperature, indicating an issue with heating or heat transfer.

The boiler is not providing the expected volume or flow rate of hot water, even if the temperature might be acceptable.

The domestic hot water has an unpleasant smell or appears discolored, which indicates issues with water quality or tank hygiene.

If there is no fault or maintenance request, the display goes to sleep after 2 minutes of inactivity. This is a normal power-saving state.

The ignition process of the burner is not optimal, described as 'too hard' or 'too bad', which can lead to ignition failures or difficult starts.

This display allows you to see the last fault that occurred in the boiler. This information is helpful for troubleshooting and diagnostics.

The boiler's internal counter indicates that the set maintenance interval has been surpassed, meaning routine servicing is due.

This warning highlights a critical safety hazard related to flammable gases, likely indicating a gas leak or the need for extreme caution when working on gas-carrying parts.