Junkers Cerastarcomfort ZWN 25 8 MFA PCB Ref. 8748300933
RefurbishedBosch JunkersPCBs (control boards)

Junkers Cerastarcomfort ZWN 25 8 MFA PCB Ref. 8748300933

85 €VAT includedIn stock · 11 units

PCB (control board): refurbished spare part that controls the ignition, modulation, and safety features of the boiler. Useful if the boiler does not ignite, locks out, or the display is unresponsive. Compatible with ZWN 25-8 MFA, ZWN 30-8 MFA (ref. 8748300933). Includes a one-year warranty and delivery within 2–4 working days in the EU.

1
Consult via WhatsApp
Delivery in 2–4 working days
1-year warranty
14-day return
Technical support

Key Data

Reference
8748300933
Brand
Bosch Junkers
Type of part
PCBs (control boards)
Available units
11 units in stock
Status
Refurbished
Warranty
1 year
Shipping
2–4 working days (EU)
Return
14 days

The same part (ref. 8748300933) equips these models. Verified compatibility; check the reference before purchasing.

Cerastar Comfort ZWN

  • ZWN 25-8 MFA
  • ZWN 30-8 MFA

Fault codes related to this part (not the entire boiler). They usually have more possible causes: first rule out electrodes, wiring/connections, and gas supply. Verified with ≥3 sources.

CodeWhat does it mean?Cause and diagnosis (this part)
F0Internal fault.Fault in the PCB/Heatronic (PCB). After checking electrical contacts and ignition cables and resetting, if the error persists, it is confirmed by replacing the PCB (or bus module if applicable).
F7Even though the appliance is turned off, a flame is detected.Humidity or defect in the PCB causes a false ionisation signal; check by drying/inspecting the PCB and, if it persists or there is damage, replace the board.
b1Coded connector not detected.The control board does not recognise the encoder; check connector/wiring. If the encoder is correct, the cause is the PCB (reading/input on PCB).
b2Internal data error.Data corruption in electronics (Heatronic/EEPROM). Try resetting to factory settings (function 8.E); if it reappears, the PCB is faulty and should be replaced.
b3Internal data error.Same origin as b2 (internal data on the PCB). After resetting to factory settings, if it persists, it confirms a fault in the printed circuit and it should be replaced.
How do I know if this PCB is for my boiler?
Verify the reference 8748300933 printed and ensure your model is on the list of compatible ones; also compare the connections with the original part.
What is it used for?
The PCB controls the ignition, modulation, sensor readings, and safety features of the boiler.
Is the boiler not igniting, locking out, or is the control board unresponsive?
After ruling out mains voltage, fuse, and connectors, a damaged PCB causes lockouts, blackouts, or erratic display. Repair the external cause before installing the new one.
Which models is it suitable for?
Part shared by various models (see Compatibility). If your model does not appear, send us a photo of the marking and we will confirm it.
Installation and recommendations
After installation, a technician must adjust the service parameters (type of gas, power settings) and check combustion and safety features.
What does refurbished mean and what coverage does it have?
Part removed from a boiler out of service, inspected and tested. Includes 1-year warranty and 14-day return policy. Delivery within 2–4 working days in the EU.

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