Ignition Transformer ZIG 2 - Saunier Duval Themis 23 - Ref. 05210600
Saunier Duval Themis 23 uses the ignition transformer ZIG 2, which is responsible for generating the spark needed to ignite the burner. When this part fails, the boiler attempts to start without being able to form a flame, which may lead to the display of fault code F.28 for ignition failure or F.29 if there are failed re-ignition attempts. This part is also compatible with other models in the Thelia range, such as Thelia 23, Thelia 623, and Thelia 23 E, among others. It is advisable to replace the transformer when these ignition failure symptoms occur.
VAT included
Consult via WhatsAppSaunier Duval boilers compatible with reference 05210600
Ignition transformer with reference 05210600. Four confirmed compatibilities: Thelia 23 and Thelia 623.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Saunier Duval Thelia 23 | Thelia | Contrasted |
| Saunier Duval Thelia 623 | Thelia | Contrasted |
| Saunier Duval Thelia 23 E | Thelia | Contrasted |
| Saunier Duval Themis 23 E | Themis | 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. 05210600 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 05210600. 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 ignition transformer 05210600 resolves.
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 ignite and there is no spark noise when starting.
Cause: If the transformer has stopped supplying current, the electrode does not generate any arc and the gas does not ignite.
Listen carefully to the start: the characteristic tapping of the spark should be noticeable; if you hear nothing, suspect the transformer before the electrode.
- 02
The spark appears weak or a different color than usual.
Cause: A transformer that starts to fail reduces the output current and the arc loses strength even though it continues to jump.
If you can see the electrode with the cover open, check if the spark is thin and yellowish instead of white and bright; it usually indicates low output current.
- 03
The ignition works sometimes and not others, without a clear pattern.
Cause: The internal winding may fail intermittently due to overheating, producing irregular arcs depending on the moment.
Note whether the fault occurs more with the boiler cold or already hot; if it worsens when hot, lean more towards the transformer than the gas.
- 04
The boiler becomes locked after several consecutive ignition attempts.
Cause: Without a reliable spark at the electrode, the control board does not recognize the flame within the safety time and locks the unit.
Check that the electrode is not dirty with soot or broken before confirming the replacement of the transformer.
- 05
There is a slight burnt smell near the ignition box.
Cause: A winding degraded by overheating may smell like burnt plastic or varnish before it completely fails.
With the boiler turned off and cold, there is a smell near the transformer; if the smell is strong, do not force any more starts and check it before continuing to use the boiler.
Fault codes from Saunier Duval that this spare part resolves.
| Code | Fault | Diagnosis and solution |
|---|---|---|
| F.28 | Ignition fault: the boiler fails to ignite the burner during startup (no flame formation after several attempts). | The ignition transformer is part of the ignition system/group (transformer, cable, connector, and electrode); if it does not generate the spark, the boiler will not ignite and shows F.28. Check: measure the output of the transformer/spark at the electrode with the boiler on demand; check the continuity of the high voltage cable and connections, and rule out gas issues (pressure, valve) and grounding problems first. |
| F.29 | Failed re-ignition attempts during operation: the flame is lost and the boiler fails to re-ignite. | Sources document 'ignition failures in the ignition transformer' as the cause of F.29; if the transformer does not produce a stable spark when reigniting after a flame loss, F.29 is triggered. Check: spark at the electrode during reignition and condition of the transformer/cable; also rule out temporary gas shortage and flue recirculation/blockage. |
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.
Saunier Duval Ignition Transformer Datasheet 05210600
- Catalogue reference
- 05210600
- Brand
- Saunier Duval
- Type of part
- Transformers
- Units in stock
- 5 units
- Status
- Refurbished
- Warranty
- 1 year
- Shipping
- 1-2 business days
- 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.
- Model code
- ZIG 2
- Voltage
- 220-240 V~
- Network frequency
- 50-60 Hz
- Spark frequency
- 10 Hz
- Maximum temperature
- 125 °C
- Certification
- DIN DVGW 88.01f142
- Conformity mark
- DVE symbol
Frequently asked questions about the ignition transformer 05210600
Is this ZIG 2 ignition transformer Ref. 05210600 compatible with my Saunier Duval boiler?
What symptoms indicate that I should replace the ZIG 2 transformer of the Themis 23?
What voltage and spark frequency does the ZIG 2 transformer support?
How many models are compatible with the transformer ZIG 2 Ref. 05210600?
What fault codes are documented for this transformer?
Where can I find more information about the transformer ZIG 2 Ref. 05210600?
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