PCB for Boiler Cerastar B50 ZWSE23-4 / Euromaxx ZWC 24-28-1MFA
If your boiler does not start, locks out, or behaves erratically, you may need the PCB for the Cerastar B50 ZWSE23-4 / Euromaxx ZWC 24-28-1MFA boiler. This control board is responsible for managing the ignition, burner modulation, pump, and safety features of the boiler. If it fails, you might see the fault code F7, which indicates issues with ignition and safety. This part is compatible with models such as the ZWC 24-1MFA 23 and ZWC 28-1MFA 23, among others. It is recommended to replace it when it shows faults that affect its operation.
VAT included
Consult via WhatsAppBosch Junkers boilers compatible with reference 8748300506
PCB with reference 8748300506. Two confirmed compatibilities: ZWC 24-1MFA 23 and ZWC 28-1MFA 23.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Bosch Junkers ZWC 24-1MFA 23 | Junkers Euromaxx | Contrasted |
| Bosch Junkers ZWC 28-1MFA 23 | Junkers Euromaxx | 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. 8748300506 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 8748300506. 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 8748300506 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
A different fault code appears each time, without a clear pattern.
Cause: The PCB interprets the signals from the sensors and relays; if it fails, it can generate erratic readings that result in various faults.
Note the exact codes that appear and when, and compare them with the manual before assuming it is the PCB.
- 02
The screen goes black or flickers when receiving power.
Cause: The power supply stage of the PCB is what turns on the display; if it is damaged, the screen does not start up correctly.
Check that the mains voltage is stable and that there are no other devices causing voltage drops on the same circuit.
- 03
The buttons on the panel do not respond even though the boiler is receiving power.
Cause: The microprocessor on the PCB is the one that reads the pulses; if it is locked, the panel stops functioning.
Try performing a complete reset (cutting off the power for a few minutes) before ruling out the PCB.
- 04
The burner ignites but turns off after a few seconds, without showing any lock.
Cause: The PCB controls the flame signal and cuts off the gas if that reading does not come through correctly.
Check that the ionization electrode is clean: a fault there manifests the same way as a PCB fault.
Fault codes for Bosch Junkers that this part resolves.
| Code | Fault | Diagnosis and solution |
|---|---|---|
| F7 | Problems with the ignition and safety of the boiler. | The ionization signal is incorrect. This can affect the ignition and safety of the boiler. If the boiler shuts down after attempting to ignite, it may be due to this part. |
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 8748300506
- Catalogue reference
- 8748300506
- Brand
- Bosch Junkers
- Type of part
- PCBs (control boards)
- Units in stock
- 3 units
- Status
- Refurbished
- Warranty
- 1 year
- Shipping
- 1-2 business days
- Return
- 14 days
Data read on the part and in the manufacturer's documentation
What we have not been able to verify does not appear here.
- Visible marking on relay (silkscreen)
- HT II-3 | CB CA CC
Manuals and technical documentation
Official documentation of the boiler, useful for locating the part and cross-referencing the fault codes.
- Bosch Junkers ZWC 28-1MFA 23 manual (PDF)Document © Bosch Junkers, provided as a technical reference.
Frequently asked questions about the PCB 8748300506
Is the brand 'HT II-3' that appears on the label of this sheet the manufacturer code?
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