421-331 Allanson Lennox Ignition Transformer
The Allanson 421-331 ignition transformer is a high-reliability, double pole unit designed specifically for Lennox oil burners. With a powerful 10,000V secondary and 120V primary input, this transformer ensures consistent ignition performance under demanding operating conditions. Built with high-temperature wire and designed to manufacturer specifications, the 421-331 provides long service life, quieter operation, and dependable ignition power.
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Key Features
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Built with high-temperature wire for durability and extended service life
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Runs cooler, quieter, and safer on oil burners
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Manufactured to Lennox OEM specifications for guaranteed fit and performance
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Meets American & European EMI/RFI noise emission standards
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Single porcelain design for durability and stability
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Provides dependable ignition source for commercial and residential oil burner applications
π Technical Specifications
Specification | Detail |
Application |
OIL |
Burner Manufacturer |
Lennox |
Burner Type |
Lennox |
Input Voltage |
120V |
Current |
23mA |
Grounding |
Mid-Point Ground |
Secondary Voltage |
10,000V |
Input Frequency |
60Hz |
Can Size |
Large Can Series |
HV Terminal |
Zinc Plated Button |
Hinge Location |
End Hinge |
Poles |
Double |
β οΈ Common Symptoms of a Failing Ignition Transformer
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Burner fails to ignite or takes multiple attempts
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Intermittent ignition or weak spark
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Sparking noise but no flame established
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Soot buildup from incomplete combustion
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Repeated lockouts requiring manual resets
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Visible cracks, burns, or arcing on transformer casing or terminals
π Shopping Tips β How to Choose the Right Replacement
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Match the Primary Voltage β This model is 120V input; check your burnerβs rating.
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Secondary Voltage & Current β Ensure compatibility with 10,000V @ 23mA ignition requirements.
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Grounding Type β The 421-331 uses mid-point ground; incorrect grounding may prevent proper ignition.
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HV Terminal & Mounting β Designed with a zinc plated button terminal and end hinge mount.
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OEM Compatibility β Built for Lennox oil burners; verify burner type for proper fit.
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Replace Proactively β If your transformer shows signs of wear, replacing early helps avoid downtime.
β Frequently Asked Questions (FAQ)
Q1: Is this transformer specific to Lennox burners?
Yes, it is designed to Lennox OEM specifications but may also fit other burners requiring the same electrical ratings.
Q2: What is the output voltage?
The secondary output delivers 10,000V at 23mA for reliable ignition.
Q3: Can I use this as a universal replacement?
It is best suited for Lennox applications, but if the specs match (voltage, grounding, and terminal type), it can be used as a replacement.
Q4: Does it reduce electrical noise?
Yes β it meets EMI and RFI standards, preventing interference with nearby equipment.
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