Junkers Cerapur Excellence ZWBE 42-2 A23 PCB Ref. 8748300905
If your boiler does not start, locks up, or behaves erratically, a technical diagnosis must confirm if you need the Junkers Cerapur Excellence ZWBE 42-2 A23 PCB (control board) Ref. 8748300905. This control board manages the ignition, burner modulation, pump, and safety features of the boiler. Symptoms of a fault may include errors such as E0, F0, or F1, which indicate internal problems in the unit. It is compatible with boilers from the ZWBE range, such as models 32-2 A, 37-2 A, and 42-2 A, among others. A technician must confirm through diagnosis if it is necessary to replace it upon detecting any of these issues.
- Type of part
- PCBs (control boards)
- Status
- Refurbished
- Catalogue reference
- 8748300905
- Warranty
- 1 year
Boilers Junkers compatible with reference 8748300905
PCB with reference 8748300905. Three confirmed compatibilities: 32-2 A and 37-2 A.
Verified compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Junkers 32-2 A | ZWBE | Verified |
| Junkers 37-2 A | ZWBE | Verified |
| Junkers 42-2 A | ZWBE | Verified |
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 the ref. 8748300905 is the part for your boiler
The part reference, model, and equipment revision must be verified against the manufacturer's documentation.
- Find the reference printed on the installed part and check whether it matches the catalogue reference 8748300905. 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 that require diagnosis on the PCB 8748300905
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
On cold mornings, the boiler has difficulty starting, but then it works well for the rest of the day.
Cause: Some faults in the PCB worsen with humidity or cold due to a solder joint or a component that loses contact when cooling down.
Check if the problem improves after a while of being on or if it always appears at the same time, to distinguish it from a fault of another part.
- 02
The fan does not start and the boiler locks up as soon as the power button is pressed.
Cause: The PCB is the one that powers and controls the fan; if that output fails, the fan does not spin and the safety mechanism prevents the start-up.
Before changing the PCB, disconnect the fan and manually check that it spins freely, without friction or mechanical blockages.
- 03
The boiler starts to ignite, cuts off halfway through the process, and gets locked with a warning.
Cause: If the PCB does not complete the ignition sequence stably, the safety mechanism interrupts the process prematurely.
Repeat the attempt a couple of times in a row and note if it always cuts off at the same point in the sequence; this helps to narrow down whether it is the PCB or another component.
- 04
The boiler does not respond to any button on the panel, not even to turn it off.
Cause: If the microprocessor on the PCB hangs, it stops reading the commands coming from the control panel.
Cut the main power for a full minute and then restore the power; if it still does not respond to the buttons, focus more on the PCB.
Junkers fault codes that require diagnosis
| Code | Fault | Technical checks |
|---|---|---|
| E0 | Fault in the electronic box (internal fault of the module/PCB). | Internal fault of the control board (Heatronic/PCB). Verify with reset and basic check; if the error persists, diagnose/replace the board. |
| F0 | Internal fault (internal fault of the control board). | Internal anomaly of the electronic control; the manufacturer advises checking connections and, if necessary, replacing the control board/PCB. Verify by resetting and checking wiring; if it reappears, replace the PCB. |
| F1 | Internal data error. | This symptom may be related to the part, but it does not confirm that it is faulty. A technician must check the equipment and its inspection according to the manual before deciding on a repair or replacement. |
| b2 | Internal data error. | Internal data fault in the electronics (Heatronic/PCB). Check connections and perform a 'factory reset' (8.E); if the code reappears, Bosch documents the replacement of the control board/PCB as a solution. |
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.
Technical sheet: Junkers 8748300905
- Catalogue reference
- 8748300905
- Uniclima internal SKU
- PLBO156
- Brand
- Junkers
- Type of part
- PCBs (control boards)
- Units in stock
- 0 units
- Status
- Refurbished
- Warranty
- 1 year
- Shipping
- Delivery time shown at checkout
- Return
- 14 days
Part data and available documentation
Contrast the label codes, PCB, and revision with the installed part; they are not necessarily equivalent references.
- voltage
- 12V
- frequency
- 50Hz
Frequently asked questions about the PCB 8748300905
Is this PCB compatible with the ZWBE 42-2 A boiler?
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