Transformer for Vaillant Boiler VMW 242-5
In Vaillant VMW boilers, the transformer for Vaillant VMW 242-5 is an essential part that generates the spark needed to ignite the burner. If it fails, you will notice that the boiler attempts to start repeatedly without being able to ignite the flame, which can lead to fault codes F.28 and F.29. This transformer is compatible with models such as VMW ES 242/3, VMW 242-3, VMW 240-5, among others. A technician must confirm through diagnosis whether it needs to be replaced when the boiler has ignition problems or locks out after several failed attempts.
- Type of part
- Transformers
- Status
- Refurbished
- Catalogue reference
- 287450
- Warranty
- 1 year
Vaillant boilers compatible with reference 287450
Ignition transformer with reference 287450. 12 verified compatibilities: VMW ES 242/3 and VMW 242-3.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Vaillant VMW ES 242/3 | Vaillant Turbo Tec / Turbo Pro (VMW) | Contrasted |
| Vaillant VMW 242-3 | Vaillant Turbo Tec / Turbo Pro (VMW) | Contrasted |
| Vaillant VMW 242-5 | Vaillant Turbo Tec / Turbo Pro (VMW) | Contrasted |
| Vaillant VMW 240-5 | Vaillant Turbo Tec / Turbo Pro (VMW) | Contrasted |
| Vaillant VMW 282-5 | Vaillant Turbo Tec / Turbo Pro (VMW) | Contrasted |
| Vaillant VM 242-5 | Vaillant Atmo Tec / VM (heating only) | Contrasted |
| Vaillant VM 282-5 | Vaillant Atmo Tec / VM (heating only) | Contrasted |
| Vaillant VC 242 E | Vaillant VC / VCM (combi-compact) | Contrasted |
| Vaillant VCM 242 E | Vaillant VC / VCM (combi-compact) | Contrasted |
| Vaillant VCM 282 E | Vaillant VC / VCM (combi-compact) | Contrasted |
| Vaillant VMI 280-7 | Vaillant VMI | Contrasted |
| Vaillant VMI 282-7 | Vaillant VMI | 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. 287450 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 287450. 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 in the ignition transformer 287450
The ignition transformer generates the high voltage for the spark of the electrodes. These are the typical symptoms and what to do:
Common symptoms and faults
- 01
The boiler does not turn on or display anything on the screen, as if it were completely off.
Cause: The transformer does not provide the necessary current, so the PCB does not start.
Measure with a multimeter if there is output at the terminals of the transformer before replacing the part; this way you can rule out that the problem is with the PCB.
- 02
The boiler shuts off by itself halfway through combustion, without triggering any clear fault code.
Cause: A winding provides sufficient current when cold, but it may fail when heated, intermittently cutting off the power supply.
Leave the boiler running for a while and measure the transformer current after it has been on for some time, comparing it with the cold measurement.
- 03
The transformer fuse blows every few days.
Cause: A component such as the fan or the solenoid valve is drawing more current than the transformer should provide.
Check the fan and solenoid valves for a short circuit before assuming the transformer is faulty.
- 04
There is a slight burning smell near the boiler's electrical panel.
Cause: The transformer has overheated, usually due to sustained overload or an internal short circuit.
Disconnect the power supply to the boiler and check if the transformer has any burn marks before handling anything else.
Vaillant fault codes that require diagnosis
| Code | Fault | Technical checks |
|---|---|---|
| F.28 | Fault during start-up: the boiler fails to ignite the burner in the start-up phase. | The ignition transformer is part of the ignition system (transformer + cable + electrode); if the transformer fails, it does not generate the high voltage for the spark, and the boiler aborts the start-up without detecting a flame. Verify: measure the transformer's output voltage to the electrode and check for a spark at each start-up; if there is no spark and the wiring/electrode are fine, the transformer is the cause. |
| F.29 | The flame goes out during operation and re-ignition attempts fail. | The Vaillant service documentation explicitly lists "the ignition transformer has a spark fault" as the cause of F.29: if the transformer does not reignite after a flame failure, the lockout is triggered. Verify: check the spark generation of the transformer during ignition retries and rule out poor grounding, gas pressure, and condensate pipe before. |
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.
Vaillant 287450 ignition transformer datasheet
- Catalogue reference
- 287450
- Uniclima internal SKU
- TCTVMW242
- Brand
- Vaillant
- Type of part
- Transformers
- Units in stock
- 3 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.
- Frequency
- 50/60Hz
- Secondary voltage/power
- 17V, 18.4VA
- Fuse
- 1.55AT
- Core
- EI50
Manuals and technical documentation
Official documentation of the boiler, useful for locating the part and cross-referencing the fault codes.
- Vaillant VMW 242-5 Manual (PDF) Document © Vaillant, provided as a technical reference.
Frequently asked questions about the ignition transformer 287450
Is this transformer suitable for the Vaillant VMW 242-5?
What output voltage does this transformer provide for the VMW 242-5?
What fuse does the transformer of the Vaillant VMW 242-5 use?
Spare parts related to Vaillant Turbo Tec / Turbo Pro (VMW)
