Siemens 26T4042559 Ignition Transformer Buyer's Guide: 240 V, 50 Hz, 8.5 kV Secondary for Worldwide Burner & Combustion Systems

The Siemens 26T4042559 ignition transformer, Model 26T4042559, is a 240 V, 50 Hz step-up transformer producing an 8.5 kV secondary at 23 mA — the spark source that ignites gas and oil burners in boilers, furnaces, ovens and process heaters. It is ordered by primary voltage, frequency, secondary voltage and secondary current, not by physical size alone.

What is a Siemens 26T4042559 ignition transformer?

A Siemens 26T4042559 ignition transformer is a sealed, oil- or resin-insulated step-up transformer that converts a 240 V, 50 Hz control supply into an 8.5 kV, 23 mA high-voltage spark at the burner electrode. Siemens builds these units for continuous-duty ignition in commercial and industrial combustion systems.

Unlike a generic high-voltage transformer, an ignition transformer is rated for the repetitive, high-temperature duty of a burner head. The 8.5 kV secondary is high enough to jump a fouled or slightly misaligned electrode gap, while the 23 mA current limit keeps the spark energetic without over-stressing insulation.

How does an ignition transformer work?

The primary winding accepts 240 V at 50 Hz from the burner control circuit. The secondary winding steps that up to 8.5 kV, which appears across the ignition electrode and ground. The resulting arc ignites the air-fuel mixture, and the flame safeguard then proves flame and holds the burner in run mode.

Because the secondary is current-limited to 23 mA, the transformer can sustain spark without drawing destructive current through the electrode circuit. That is why matching the mA rating matters as much as matching the kV rating when replacing a Siemens 26T4042559.

Siemens 26T4042559 specifications

Only the values above are confirmed for this model. Do not assume a 60 Hz rating or a different secondary current — verify against the burner OEM nameplate before ordering.

Which burner systems use the Siemens 26T4042559?

The 26T4042559 suits commercial and industrial burners that run on a 240 V, 50 Hz supply — common across Europe, the Middle East, Africa, Asia and much of Latin America. Typical hosts include packaged boilers, process heaters, bakery ovens, asphalt plant burners and industrial furnaces.

In 60 Hz markets such as North America, a 50 Hz transformer should not be substituted without checking the burner control's frequency tolerance. Where the burner is 60 Hz, source the 60 Hz equivalent rather than forcing a 50 Hz unit.

How to select the right ignition transformer

1. Match primary voltage: confirm 240 V at the burner control terminals — not 120 V or 230 V nominal.
2. Match frequency: 50 Hz for this model; specify 60 Hz where the supply requires it.
3. Match secondary kV: 8.5 kV must suit the electrode gap and cable length.
4. Match secondary mA: 23 mA must align with the burner's ignition circuit design.
5. Check duty and environment: confirm ambient temperature, mounting position and enclosure rating.
6. Verify flame safeguard compatibility: the transformer must work with the existing control sequence.

Related Siemens combustion and control accessories

Ignition transformers rarely fail alone. Burner panels also carry contactors, motor starters and control accessories, and 3G Electric stocks a broad Siemens range across those categories. The table below shows representative Siemens accessories available alongside the 26T4042559.

Step up to the surge suppressor when burner panels experience nuisance contactor coil failures. Step up to the auxiliary switch when the control sequence needs flame or run-status feedback. For small-scale automation around the burner, the Siemens LOGO! Software 6ED10580BA080YA1 supports logic creation and simulation.

Installation and troubleshooting notes

Ignition transformers are high-voltage devices. Isolate and lock out the burner before service, discharge the secondary, and confirm the electrode gap and ceramic insulator condition before replacing the transformer. A weak spark is often an electrode or cable problem, not a transformer failure.

According to Siemens combustion component documentation, ignition transformers must be matched to the burner control's primary voltage, frequency and secondary rating; substituting a different rating can cause unreliable ignition or insulation failure.

Worldwide sourcing and export considerations

3G Electric supplies the Siemens 26T4042559 and related combustion and control accessories to buyers worldwide. We handle export documentation and can quote on incoterms-neutral terms so international buyers can align freight, duty and delivery with their own logistics. Pricing is quoted in USD.

Because 50 Hz and 60 Hz markets differ, always state your supply frequency when requesting a quote. If your site runs 60 Hz, we will help identify the correct frequency-rated equivalent rather than shipping a mismatched unit.

Frequently asked questions

What is the Siemens 26T4042559 used for?
The Siemens 26T4042559 is a burner ignition transformer used to generate an 8.5 kV, 23 mA spark that ignites gas or oil in commercial and industrial burners. It runs from a 240 V, 50 Hz primary supply and is common in boilers, furnaces and process heaters.

Can I use a 50 Hz transformer on a 60 Hz supply?
Not safely without verification. A 50 Hz ignition transformer on a 60 Hz supply may run at reduced flux and altered secondary output. For 60 Hz markets, specify a 60 Hz-rated equivalent and confirm compatibility with the burner control before ordering.

How do I choose between ignition transformer models?
Match four values: primary voltage (240 V), frequency (50 Hz), secondary voltage (8.5 kV) and secondary current (23 mA). Then confirm duty, ambient temperature and flame safeguard compatibility. Never upsize kV or mA without checking the electrode and control design.

Where can I buy the Siemens 26T4042559 in Worldwide?
3G Electric supplies the Siemens 26T4042559 and related Siemens combustion and control accessories worldwide, with export documentation and USD quoting. Contact us with your supply frequency and burner details for a quote and lead time.

What causes an ignition transformer to fail?
Common causes include cracked secondary insulation, moisture ingress, a shorted or misaligned electrode, and continuous duty beyond the transformer's rating. Check the electrode gap and high-voltage cable before replacing the transformer.

Key takeaways

• The Siemens 26T4042559 is a 240 V, 50 Hz ignition transformer with an 8.5 kV, 23 mA secondary.
• Match primary voltage, frequency, secondary kV and mA before ordering.
• 50 Hz and 60 Hz markets require different frequency-rated units.
• 3G Electric supplies Siemens combustion and control accessories worldwide with export documentation.
• Confirm electrode condition before assuming the transformer has failed.

Contact 3G Electric for a quote on the Siemens 26T4042559, sizing assistance and technical support. We stock 78+ related products across Siemens combustion, control and automation categories and ship worldwide.