Junkers/Bosch Control Board 8 748 300 233 · PCB 8 748 301 107 for ZWE 24.3 EuroStar

Application to the exact variant pending confirmation. Bosch/Junkers printed circuit board of the boiler's electronic control. The subsequent reference 8 748 300 267 0 corresponds to the control assembly of the Eurostar -3 series. Before replacing the PCB, check power supply, wiring, sensors, and correspondence between references.

Type of part: Junkers
Status: Refurbished
Catalogue reference: 8748300233
Warranty: 1 year

VAT included Stock · 1 unit

Compatibility

Boilers Junkers compatible with reference 8748300233

Junkers with reference 8748300233. 0 verified compatibilities. There are 2 other models that we are still checking.

Models pending verification

These models are associated with this reference, but we have not finished verifying them yet, so we do not consider them compatibleIf your boiler is one of them, send us a photo of the part you are going to replace and we will verify it before you purchase.

Junkers ZE 24-3 MFAD 23 S2800	Junkers	Unconfirmed
Junkers ZWE 24.3 / EuroStar	Junkers	Unconfirmed

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 reference 8748300233 is the part for your boiler?

The part reference, model, and equipment revision must be verified against the manufacturer's documentation.

Look for the label on the integrated circuit: it should say 8 748 300 233 (in the bag, 8748300233). The integrated circuit is marked HTBL05.62 and FD767.
Turn it over: on the back, it will be screen printed 8 748 301 107. On the plate, it reads "8 748 300" printed and the suffix "233" added.
Don't confuse it with 8 748 300 267: Bosch lists it as the successor to 233, and the official parts breakdowns of the series carry 267. It's a different code.
Check the rating plate of your boiler: it should be a Junkers ZWE 24.3 / EuroStar.
if they match, call us at 911 17 77 77 with the model of your boiler.

Diagnosis and fault codes

Symptoms that require diagnosis in the junkers 8748300233

Common symptoms and faults

01
The boiler does not ignite and shows EA.
Cause: Lack of gas, air in the line, or an ionization electrode that does not detect the flame.
Check the gas valve and press reset once. If it appears again, have a technician check it.
02
The boiler displays E0 or F0 on the screen.
Cause: Internal fault in the electronics, almost always in the PCB; sometimes it is defective ignition connections or wires.
Check the electrical connections and the ignition cable. If the fault code persists, have a technician check it: the PCB may need to be replaced.
03
E0 appears on the boiler display.
Cause: Internal fault in the PCB (control board).
Have a technician check it. The manual indicates to replace the PCB.
04
b1 appears on the boiler display.
Cause: The PCB does not recognize the encoder plug.
Have a technician check it: verify the encoder plug.
05
EA appears on the display and the reset button is flashing.
Cause: There is no ionization current: the flame is not detected.
Have a technician check it.

Junkers fault codes that require diagnosis

Code	Fault	Technical checks
E9	Overtemperature thermostat (safety limiter) activated.	Check that the installation pressure is above 0.5 bar and that the pump is not blocked. If it persists, have a technician check it.
d3	Bridge 161 is missing on the PCB: external safety connector poorly inserted or without bridge.	Check that the connector is properly inserted and that the bridge exists according to the electrical diagram. If it is correct, point it to the PCB; have a technician check it.
E2	Faulty NTC sensor for flow (heating).	Check the flow sensor and its connection cable. If the sensor is fine, point to the PCB; have a technician check it.
EA	No ignition flame detected.	Check that there is gas and press reset once. If it repeats, it points to the ionization electrode or the PCB; have a technician check it.
E0	Internal fault in the PCB (control board).	Check the electrical connections and the ignition cable. If the fault code persists, the PCB needs to be replaced; have a technician check it.
F0	Internal electronic error (internal fault of the PCB or its connections).	Check the electrical connections and the ignition cable. If the fault code persists, the PCB is usually the part that needs to be replaced; have a technician check it.
b1	The encoder plug is not recognized by the PCB.	Have a technician check it: ensure that the encoder plug is properly connected and in good condition.

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

Technical sheet: Junkers 8748300233

Catalogue reference: 8748300233
Uniclima internal SKU: PLC267
Brand: Junkers
Type of part: Junkers
Units in stock: 1 unit
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.

Photographed display: 2 digits
Screen-printed fuse: T2.5A
Integrated circuit marking: HTBL05.62; FD767
Integrated circuit label: 8 748 300 233
Stock code: 8748300233
Gray component: 1µF K 275V~
Printed PCB silkscreen: 8 748 300
Handwritten/printed suffix on PCB: 233
Added in pencil separately on the CI label.: 78
Silkscreen code on the back of the PCB: 8 748 301 107
Barcode number on the back: 258970005442
Visible marking on PCB: 9605
Official Bosch catalog · successor part 8 748 300 267 0 (PCB) — Predecessor: 8748300233 · Bosch Catalog
Official Bosch catalog · successor part 8 748 300 267 0 (PCB) — Use: ZWE 24-3A../K.., ZWE 28-3A.. · Z.E 24-3 MFK/MFA.. · Bosch catalog
Official Bosch catalog · successor part 8 748 300 267 0 (PCB) — Availability of the successor: Not available · Bosch catalog
Identification — Integrated circuit label: 8 748 300 233
Identification — Integrated circuit marking: HTBL05.62; FD767
Identification — Printed PCB silkscreen: 8 748 300
Identification — Handwritten/printed suffix on PCB: 233
Identification — Screen-printed code on the back of the PCB: 8 748 301 107
Identification — Code on bag: 8748300233
Identification — Number under barcode on the back: 258970005442
Identification — Visible marking on PCB: 9605
Display photographed: 2 digits
Technical sheet: Screen-printed fuse: T2.5A
Componente gris: 1µF K 275V~
Technical sheet — Added in pencil separately on the CI label: 78
Inventory data — Application indicated in inventory: ZWE 24.3 / EuroStar
Pending applications to verify: ZWE 24.3 / EuroStar — compatibility noted; pending confirmation by variant.

Before purchasing

To confirm: Junkers ZE 24-3 MFAD 23 S2800 — it is given with the 8748300233. The official lists for the ZE/ZWE 24-3 MFA family show the 8 748 300 267 in the position of the PCB, without mentioning this variant. To confirm.
Do not confuse: 8 748 300 267 — PCB that replaces the 233 Bosch (8 748 300 267 0) and Eurostar; it is the one provided by the official parts lists of the series — It is another code: this unit is marked with 233. They say that the 267 replaces the 233, not that they are the same part.
They talk about the Junkers code 8 748 300 233 and its successor 8 748 300 267, which is the one provided in the official breakdowns of the series. The code 8 748 301 107 is the circuit code, marked on the part.
To confirm: The 8 748 300 233 is linked to a Junkers Eurostar -3 control board in the official Bosch catalog. Discrepancy: the official lists ZE/ZWE 24-3 and the Bosch parts breakdown for the series show the 8 748 300 267 in the position of the control board and not the 233; Bosch presents it as a predecessor.
Pending registered applications to confirm by model, variant, or programming: Junkers ZWE 24.3 / EuroStar.

Frequently Asked Questions

Frequently asked questions: junkers 8748300233

How do I identify the Junkers 8 748 300 233 PCB?

Look for the label on the integrated circuit: it has 8 748 300 233 (on the bag, 8748300233). The integrated circuit is marked HTBL05.62 and FD767. On the back, it is printed 8 748 301 107 and, under the barcode, 258970005442. Compare all those markings with those on your PCB.

Is it compatible with my Junkers ZWE 24.3 / EuroStar?

The compatibility of this variant is pending confirmation. Registered application: this PCB for the Junkers ZWE 24.3 / EuroStar. The official spare parts lists for the ZE/ZWE 24-3 indicate the position of the PCB as 8 748 300 267 and not 233. The 8748300233 for the ZE 24-3MFAD 23 S2800; the lists for that family indicate 267 there, although none mention that variant. For any other boiler, please send us a photo of the label of the PCB and the specification plate of the boiler from Contact.

What is the difference between 8 748 300 233 and 8 748 300 267?

The official Bosch catalog lists 8748300233 as the predecessor of the PCB 8 748 300 267 0, and Eurostar spare parts state that 8748300267 replaces 8748300233. The official spare parts lists for the ZE/ZWE 24-3 series show 8 748 300 267 in that position and not 233. Bosch also indicates that 267 0 is no longer available. They are two different codes and this unit carries 233.

What do the codes 8 748 300 233 and 8 748 301 107 on the PCB mean?

To confirm: 8 748 300 233 is the code for the integrated circuit label: a Bosch spare part reference from Junkers. 8 748 301 107 is the code for the circuit, printed on the back. HTBL05.62 and FD767 are the markings on the integrated circuit.

How is the code on the board read if it only says "8 748 300" printed?

The PCB is printed with 8 748 300 and the 233 added (handwritten or overprinted): together they make 8 748 300 233, the same code as the label on the integrated circuit. Additionally, there is a "78" added in pencil, separated from the code.

What other boilers use this PCB or its successor?

The compatibility of this variant is pending confirmation. For the 233, Registered application: the ZWE 24.3 / EuroStar and the ZE 24-3MFAD 23 S2800. The official lists of the ZE/ZWE 24-3 MFA family mention 8 748 300 267, although none specify this variant. Bosch's official catalog lists the successor 8 748 300 267 0 in the control sets of the ZWE24-3MFKD23S3692, ZWE24-3MFAD23S3600, ZWE24-3MFA5S0700, and ZWE28-3MFA5S0700. The Italian catalog lists 8748300267 for Cerastar ZE 24-3 MFA/MFK and ZWE 24-3/28-3 HA.

Who should install the PCB?

A qualified technician: the boiler is gas-powered. Disconnect the boiler from the power supply before touching it and have the technician check the operation after the replacement.

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Junkers/Bosch Control Board 8 748 300 233 · PCB 8 748 301 107 for ZWE 24.3 EuroStar