Junkers PCB Zwbc 30 2 C23 Ref. 8748300923
If the boiler does not start, locks out, or exhibits erratic behavior, you may need the Junkers Zwbc 30 2 C23 PCB Ref. 8748300923. This control board is responsible for managing the ignition, burner modulation, pump, and safety features of the boiler. A fault in this component can lead to the appearance of error F0: Internal error. It is compatible with models from the Cerapur Comfort ZWBC range, such as the ZWBC 24-2C, ZWBC 25-2C, ZWBC 28-2C, and ZWBC 30-2C, among others. It should be replaced when it shows faults that affect the operation of the boiler.
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Consult via WhatsAppBosch Junkers boilers compatible with reference 8748300923
PCB with reference 8748300923. Four confirmed compatibilities: ZWBC 24-2C and ZWBC 25-2C.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Bosch Junkers ZWBC 24-2C | Cerapur Comfort ZWBC (2C) | Contrasted |
| Bosch Junkers ZWBC 25-2C | Cerapur Comfort ZWBC (2C) | Contrasted |
| Bosch Junkers ZWBC 28-2C | Cerapur Comfort ZWBC (2C) | Contrasted |
| Bosch Junkers ZWBC 30-2C | Cerapur Comfort ZWBC (2C) | Contrasted |
Can't see your model or have questions? The printed reference takes precedence. How to check it · Send us a photo via WhatsApp.
How to check if ref. 8748300923 is the part for your boiler
What determines it is not the boiler model, but the reference printed on the part you already have installed.
- Find the reference printed on the installed part and check whether it matches the catalogue reference 8748300923. If it is not visible, do not identify the part from its shape alone.
- Check the full boiler model on its data plate and look for it in the model associations on this page.
- Compare the connections and physical body with the original part before installation.
- If anything is unclear, send us a photo of the marking via WhatsApp before placing your order.
Symptoms and faults that the PCB 8748300923 resolves
The PCB controls the ignition, modulation, and safety features of the boiler. These are the typical symptoms and what to do:
Common symptoms and faults
- 01
The display flickers or has some segments turned off, although the boiler continues to operate.
Cause: The PCB powers and manages the display, and the wear of its components causes intermittent faults in that circuit.
Check that the mains voltage is stable, without drops, before replacing the PCB due to a display fault.
- 02
The boiler turns on and off by itself several times in a row, without anyone touching anything.
Cause: The PCB manages the ignition and shutdown cycle; if its logic fails, it can cause unnecessary resets.
Check if the fault coincides with power supply interruptions before attributing it to the PCB.
- 03
The pump or the three-way valve continue to operate even though heating and hot water are no longer needed.
Cause: A relay on the PCB can get stuck and keep that output activated even though the command has already stopped.
Make sure there is no active real demand (thermostat or open tap) before declaring the relay faulty.
- 04
The remote control or modulating thermostat is not communicating: it does not display the temperature nor allows for adjustment.
Cause: The communication between the control and the boiler goes through the PCB, and a fault at that stage leaves the control without a signal.
Check the bus cable connections on the terminal block of the PCB before replacing it.
Fault codes for Bosch Junkers that this part resolves.
| Code | Fault | Diagnosis and solution |
|---|---|---|
| F0 | Internal error. | The PCB (control board) has an internal fault (e.g., A/D converter, memory, or power supply), triggering the "F0". Check voltages and wiring, encoder connections, and if the error persists after reset and testing, replace the PCB 8748300923. |
These symptoms can have more than one cause. If your boiler displays a fault code, send it to us via WhatsApp along with a photo of the labeling, and we'll tell you if this is the part.
Data sheet for the Bosch Junkers PCB 8748300923
- Catalogue reference
- 8748300923
- Brand
- Bosch Junkers
- Type of part
- PCBs (control boards)
- Units in stock
- 2 units
- Status
- Refurbished
- Warranty
- 1 year
- Shipping
- Delivery time shown at checkout
- Return
- 14 days
Frequently asked questions about the PCB 8748300923
Does this PCB Ref. 8748300923 work for my Baxi Roca Cerapur Comfort or ZWBC24-2C23 boiler?
Why does the display in the photo show "88" on this PCB?
My boiler is a ZWBC25-2C23S3700 and it's not on the list as is, will this PCB work for me?
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