Saunier Duval Thelia 23 Ignition Transformer Ref. ZIG 2
The ignition transformer Saunier Duval Thelia 23 2 generates the spark needed to ignite the burner of the boiler. If it fails, the boiler will attempt to start without a flame, which can lead to fault codes F.28 or F.29, indicating ignition or re-ignition problems. This transformer is compatible with boilers from the Thelia range, such as Thelia 23, Thelia 623, and Thelia 23 E, as well as with the model Themis 23 E. It should be replaced when the boiler shows ignition faults or lockouts during startup.
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 tries to ignite but no spark is generated at the burner.
Cause: The transformer does not generate the high voltage necessary for the spark to jump at the electrode.
Check that the high voltage cable is properly connected to the electrode and that it is not damaged before replacing the transformer.
- 02
The ignition attempt can be heard, but the boiler locks out after a few seconds with a flame fault.
Cause: Without a spark, the control board does not detect a flame and cuts the cycle for safety after several attempts.
Check the display to see if the fault code indicates an ignition failure and not another cause, such as lack of gas or pressure switch, before replacing the part.
- 03
The electrode does not show any visible arc even though the boiler attempts to ignite.
Cause: A transformer with damaged winding stops delivering voltage even though it receives current.
Check the distance and cleanliness of the electrode and its connection to the casing; a dirty or improperly positioned electrode can produce the same symptom without the transformer failing.
- 04
The boiler gets locked as soon as it starts, always at the same point in the cycle.
Cause: Without output voltage from the transformer, the ignition cycle repeats and gets stuck in the same phase.
Check that 220-240V of current reaches the transformer connector before declaring it faulty.
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
- ZIG 2
- voltage
- 220-240V~
- Mains frequency
- 50-60Hz (last digit not entirely clear in the photo)
- Spark frequency
- 10 Hz
- power
- 2.5 VA
- Maximum temperature
- 125°C tmax
- CE certification
- CE-0085AU0189
- certification
- DIN DVGW 88.01f142
Frequently asked questions about the ignition transformer 05210600
What model of transformer does the Saunier Duval Thelia 23 use?
Which boilers are compatible with the ZIG 2 transformer?
What fault indicates that the transformer of the Thelia 623 needs to be replaced?
What voltage and power does the ZIG 2 transformer operate at?
How many models are compatible with the ignition transformer Saunier Duval ZIG 2?
What fault codes are documented for this transformer?
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