Junkers Euromaxx ZWC28-1MF2A Bosch PCB Ref. 8748300533

The Bosch Junkers Euromaxx ZWC28-1MF2A PCB is the component responsible for controlling the ignition, burner modulation, pump, and safety features of the boiler. When this part fails, the boiler may not start, become locked, or exhibit erratic operation, which can be reflected in the fault code F0: Internal fault/PCB fault. This board is compatible with several boiler models, such as the Euromaxx ZWC 24/28 and the Euromaxx ZWC/ZWB 28/32, among others. A technician must confirm through diagnosis whether it needs to be replaced if you experience ignition problems or if the boiler shows unusual behaviors.

Type of part: PCBs (control boards)
Status: Refurbished
Catalogue reference: 8748300533
Warranty: 1 year

VAT included Stock · 5 units

Compatibility

Junkers boilers compatible with reference 8748300533

PCB with reference 8748300533. Six confirmed compatibilities: ZWC24/28-1MFA 23 and ZWC24/28-1MFA 31.

Proven compatibility

Boiler model	Family	Verification
Junkers ZWC24/28-1MFA 23	Euromaxx ZWC 24/28	Contrasted
Junkers ZWC24/28-1MFA 31	Euromaxx ZWC 24/28	Contrasted
Junkers ZWC24/28-1MFK 23	Euromaxx ZWC 24/28	Contrasted
Junkers ZWC24/28-1MFK 31	Euromaxx ZWC 24/28	Contrasted
Junkers ZWC28/32-1MFA 23	Euromaxx ZWC/ZWB 28/32	Contrasted
Junkers ZWC28/32-1MFA 31	Euromaxx ZWC/ZWB 28/32	Contrasted

Can't see your model or have questions? The printed reference takes precedence. How to check it · Send us a photo via WhatsApp.

Guide

How to check if ref. 8748300533 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 8748300533. 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.

Diagnosis and fault codes

Symptoms that require diagnosis on the PCB 8748300533

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 does not start, it remains in standby forever.
Cause: The PCB manages the entire ignition sequence; if the microcontroller fails, the start command never reaches the burner.
Check that the room thermostat is calling for heat and that the water pressure is correct before ruling out the PCB.
02
The display turns off by itself or flickers for no reason.
Cause: The screen is directly dependent on the power supplied by this PCB; a fault in its circuit causes flickering or interruptions.
Turn off the power and plug the boiler back in: if the display resets and fails again shortly after, point to the PCB.
03
The controls do not change anything, the temperature remains fixed no matter what happens.
Cause: The microcontroller on the PCB interprets the commands from the controls; if it fails, it stops processing any changes.
Change the temperature of domestic hot water and heating separately: if neither responds, the problem is with the PCB, not with a specific control.
04
An error code appears on the display and the boiler locks out.
Cause: The fault codes indicate which part of the system controlled by the PCB has failed, whether it is ignition, flame, or a sensor.
Note the exact code displayed and consult your model's manual to confirm that it points to the electronic control before replacing the PCB.

Junkers fault codes that require diagnosis

Code	Fault	Technical checks
F0	Internal fault/PCB fault.	Internal fault of the PCB (Heatronic/PCB). Check power supply, connectors/plugs, fuses, and RAM/eBus wiring; if it persists, 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.

Technical data

Data sheet for the Junkers 8748300533 PCB.

Catalogue reference: 8748300533
Uniclima internal SKU: PLCEXX28
Brand: Junkers
Type of part: PCBs (control boards)
Units in stock: 5 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.

Code in the microcontroller (chip): 8744901284
Batch code/date on label: 0F 14 16 FD 367
main capacitor: 1000 µF / 63V

Frequently Asked Questions

Frequently asked questions about the PCB 8748300533

Does this PCB fit my Junkers Euromaxx ZWC28-1MF2A?

Yes, it is compatible with Euromaxx ZWC24/28 and ZWC28/32 in versions 1MFA23, 1MFA31, 1MFK23, 1MFK31, 1MF2A, 1MF2K, and 1MFA (with and without suffix 23/31); please check the exact model of your boiler.

What fault of the Euromaxx ZWC28 does this PCB solve?

It should be checked when the boiler does not ignite, does not respond to the controls, or displays a fault code on the panel. Replacement requires a technical diagnosis.

How do I check that the code on my PCB matches this reference?

The commercial reference is 8748300533, but the code 8744901284 is engraved on the microcontroller of the part: both identify the same PCB.

What capacitor is used in the PCB 8748300533 of the Euromaxx?

The main capacitor is 1000 µF / 63V, according to the part label.

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1-year warranty reviewed and tested

14-day return uninstalled parts

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Junkers Euromaxx ZWC28-1MF2A Bosch PCB Ref. 8748300533