Allanson Transformers 421-340 Transformer

The Allanson 421-340 Ignition Transformer is a heavy-duty ferromagnetic transformer engineered specifically for Armstrong and ESSO burners. Designed for constant duty, this double-pole transformer operates with a 120Vac supply voltage and delivers a consistent 10,000V secondary voltage at 23mA. Its mid-point ground configuration and Rajah connector HV terminal ensure a secure electrical interface for high-demand oil burner ignition systems. Built with a large can size and single porcelain design, it facilitates superior heat dissipation and noise reduction, meeting both American and European emission standards. This unit includes an external junction box for simplified field wiring in residential or commercial applications. For technicians troubleshooting intermittent ignition or weak spark, the 421-340 provides the stable high-voltage output required to maintain combustion efficiency in legacy and modern oil burner systems.

Key Benefits for Technicians:

• High-Voltage Stability: Consistent 10,000V output ensures reliable arc production for oil burner ignition.
• Thermal Management: Engineered to run cooler during constant duty cycles, extending the operational life of internal components.
• EMI/RFI Suppression: Advanced shielding protects sensitive electronic controls from electromagnetic interference.
• Simplified Mounting: The large can design and external junction box allow for direct replacement in Armstrong/ESSO burner housings.

Common Questions:

Is the Allanson 421-340 compatible with electronic ignitor bases?
This is a ferromagnetic transformer, not an electronic ignitor. It is designed legacy systems requiring a double-pole transformer with a mid-point ground and specific physical dimensions for Armstrong or ESSO hardware.

How do I identify a failing 10,000V ignition transformer?
Common symptoms include a weak orange spark instead of a crisp blue arc, cracked porcelain insulators, or excessive noise emission during the ignition sequence. This 23mA unit is the direct replacement to restore peak performance.

Does this unit support 240V input?
No, the 421-340 is rated specifically for 120Vac supply voltage. Verify your primary power source before installation.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.

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