PCB Immergas Zeus Maior 21/24 Ref. 018509
The Immergas Zeus Maior boilers use the Immergas Zeus Maior 21/24 PCB, which is responsible for controlling the ignition, burner modulation, pump, and safety features of the boiler. When it fails, the boiler may not start, become locked, or behave erratically, displaying the fault code E14, which indicates a blocked ignition control unit. This PCB is compatible with the Zeus 21 Maior and Zeus 24 Maior models, as well as some from the Avio Maior range. A technician must confirm through diagnosis whether it needs to be replaced when these malfunction symptoms are detected.
- Type of part
- PCBs (control boards)
- Status
- Refurbished
- Catalogue reference
- 018509
- Warranty
- 1 year
Immergas boilers compatible with reference 018509
PCB with reference 018509. Four confirmed compatibilities: Zeus 24 Maior and Zeus 21 Maior.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Immergas Zeus 24 Maior | Zeus Maior | Contrasted |
| Immergas Zeus 21 Maior | Zeus Maior | Contrasted |
| Immergas Avio 24 Maior | Avio Maior | Contrasted |
| Immergas Avio 21 Maior | Avio Maior | 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 ref. 018509 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 018509. 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 018509
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 won't start: no lights or display turn on, as if it's not receiving power.
Cause: The PCB is the brain that manages ignition; if its power supply stage fails, the unit becomes completely dead even if power is reaching it.
Check the fuse on the PCB itself and make sure there is 230V at the input before declaring it faulty.
- 02
A lockout code appears on the display and doesn't clear even when turning off and on.
Cause: The control electronics detect an anomaly (flame, sensor, pressure) and lock the equipment for safety.
Note the exact fault code and try a full reset by cutting the power for a few seconds; many lockouts are caused by a sensor or the wiring, not the PCB.
- 03
The thermostat or the room control no longer sends commands to the boiler; it operates on its own.
Cause: The communication module integrated into the PCB loses dialogue with the external regulator.
Check the bus connection or the thermostat wires before replacing the PCB.
- 04
You can hear something trying to start, but the pump or the burner do not manage to turn on.
Cause: An output relay on the PCB does not close the contact, and the command does not reach the component that should start.
Listen for the click of the relay when calling for heat; if you don't hear it, first measure the voltage at the corresponding output connector.
Immergas fault codes that require diagnosis
| Code | Fault | Technical checks |
|---|---|---|
| E14 | Ignition control unit locked (incorrect PCB-control unit connection) / flue pressure switch fault | The modulation PCB 1.018509 can cause E14 if its interface/power supply with the ignition control board fails, leaving the PCB–control board connection "not OK". Check the continuity of the harness, the control output from the PCB to the control board (relay/start command), and ensure voltage is present at ignition; if the command does not come from the PCB, replace 1.018509. |
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 Immergas PCB 018509
- Catalogue reference
- 018509
- Uniclima internal SKU
- PLIM076
- Brand
- Immergas
- 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.
- PCB manufacturer
- Immergas (silkscreened logo next to connector J9)
- Transformer model
- B5033BA
- Transformer batch code
- 461/03
- Approval marking
- CE
Frequently asked questions about the PCB 018509
Is this PCB compatible with the Immergas Zeus 24 Maior boiler?
Which boiler models are compatible with the PLIM076 PCB?
What fault code is related to this PCB?
What transformer does the PCB of the Immergas Zeus Maior 21/24 need?
Does the PCB have a CE mark?
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