Junkers Eurosmart PCB ZWA 24 1 AM23 S2800 3500 Ref. 8748300561
Junkers Eurosmart ZWA 24-1 includes the Junkers Eurosmart ZWA 24 1 AM23 S2800 3500 PCB (control board), which controls the ignition, burner modulation, pump, and safety features of the boiler. If faults occur, the boiler may fail to start, lock out, or operate erratically. Symptoms such as the reset button flashing at 1 Hz indicate a lockout due to ignition failure or overheating, while at 4 Hz it suggests a safety lockout. This board is compatible with models such as ZWA 24-1 AM 23, ZWA 24-1 KM 23, and others in the Eurosmart range. It is replaced when these issues or lockouts are detected.
Junkers boilers compatible with reference 8748300561
PCB with reference 8748300561. Six confirmed compatibilities: ZWA 24-1 AM 23 and ZWA 24-1 KM 23.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Junkers ZWA 24-1 AM 23 | Junkers Eurosmart ZWA 24-1 | Contrasted |
| Junkers ZWA 24-1 KM 23 | Junkers Eurosmart ZWA 24-1 | Contrasted |
| Junkers ZWA 24-1 AM 31 | Junkers Eurosmart ZWA 24-1 | Contrasted |
| Junkers ZWA 24-1 KM 31 | Junkers Eurosmart ZWA 24-1 | Contrasted |
| Junkers ZWA 24-1 A 23 | Junkers Eurosmart ZWA 24-1 | Contrasted |
| Junkers ZWA 28-1 AM 23 | Junkers Eurosmart ZWA 28-1 | 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 the ref. 8748300561 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 8748300561. 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 8748300561 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 boiler shows no signs of life, neither indicators nor display.
Cause: The PCB is not working and is not sending power to the rest of the electronic installation.
Check the input power supply and the fuse on the PCB before replacing it.
- 02
The boiler ignites the burner for a moment and then stops, and this happens several times in a row.
Cause: The gas valve relay can fail on the PCB and cut off the supply when igniting the flame.
Check the ignition and ionization electrodes before replacing the PCB, as they can produce the same symptom.
- 03
The boiler's indicators are flashing in a fixed pattern and the unit does not start.
Cause: That blinking is usually the code that the PCB uses to indicate the detected fault.
Count the blinks and compare them with the manufacturer's fault code table before deciding which part to replace.
- 04
The hot water responds poorly: sometimes it heats up when the tap is opened and other times it does nothing.
Cause: If the PCB does not process the signal from the flow sensor correctly, it does not activate the ignition when it should.
Check that the flow detector and its wiring are in good condition before inspecting the PCB.
- 05
The boiler stops by itself after running well for a while.
Cause: A component of the PCB that degrades with heat may fail only after a period of operation.
Note if the time until the cutoff decreases with use: if so, it points to an internal fault of the PCB.
Fault codes from Junkers that this part resolves.
| Code | Fault | Diagnosis and solution |
|---|---|---|
| The reset button flashes at 1 Hz (once per second) | Fault indicator: lockout due to ignition failure/overheating/internal fault. | A defective PCB can cause this condition by failing in flame control, power supply, or signal management; check by following Test D in the manual (voltages at ST20/ST2, wiring/ionisation control) and, if all peripherals are correct, replace the PCB. |
| The reset button flashes at 4 Hz (four times per second) | Safety/evacuation lockout (pressure switch/NTC/fan/encoder connector). | If the PCB does not power/read the pressure switch, NTC, or the encoder connector correctly, the unit enters 4 Hz; check according to Test E (encoder connector, NTC/pressure switch inputs, continuity and 5 V) and, if the sensors/wiring are ruled out, replace the PCB. |
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 Junkers 8748300561 PCB.
- Catalogue reference
- 8748300561
- Brand
- Junkers
- Type of part
- PCBs (control boards)
- Units in stock
- 3 units
- Status
- Refurbished
- Warranty
- 1 year
- Shipping
- Delivery time shown at checkout
- 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.
- Code printed on mounted relay
- 8 737 702 723 (Z 10003, KW-G 06/13)
- Electrical insulation class
- HT II - 2a / CC CA CA
Frequently asked questions about the PCB 8748300561
For which versions of the Junkers ZWA24-1 is this PCB compatible?
What information can be read on the plate of the Junkers ZWA24-1 KM31?
Spare parts related to Junkers Junkers Eurosmart ZWA 24-1
