421-104 Allanson Ignition Transformer – 120V, 60Hz, Mid-Point Ground
The Allanson 421-104 ignition transformer is a dependable replacement unit designed to provide a strong, consistent ignition source for oil burner applications. Built to manufacturer specifications, it ensures reliable performance, long life, and safe operation in commercial, residential, and industrial systems.
✅ Key Features
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Mid-Point Ground Design for reliable ignition performance
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120V, 60Hz input – standard North American rating
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Durable construction for long service life
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Runs cooler and quieter than many OEM replacements
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Meets EMI/RFI standards for reduced noise interference
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Dependable Power for consistent burner operation
📊 Specifications
| Specification | Detail |
|---|
| Part Number |
421-104 |
| Application |
Oil Burner Ignition |
| Input Voltage |
120V |
| Frequency |
60Hz |
| Grounding |
Mid-Point Ground |
| Secondary Voltage |
10,000V (typical) |
| Current |
23mA (standard rating) |
| Poles |
Double (ferromagnetic) |
| Can Style |
Large Can Series |
🛠️ Common Symptoms That Indicate Replacement
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Weak or inconsistent spark at electrodes
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Frequent burner lockouts
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No ignition despite proper fuel delivery
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Transformer runs excessively hot or noisy
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Cracked or burned insulation on terminals
🛒 Shopping Tips
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Confirm model number – Ensure you need 421-104 (not a similar series like 421-331 or 421-BT models).
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Check burner specs – Verify grounding type (Mid-Point Ground).
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Inspect your current transformer – Look for physical damage, corrosion, or weak spark output.
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Keep a spare – Many service techs recommend having an extra on hand to minimize downtime.
❓ Frequently Asked Questions (FAQ)
Q1: What burners is the 421-104 compatible with?
A: It is designed for oil burners requiring a 120V, 60Hz, mid-point ground transformer. Always check your burner’s manual for exact compatibility.
Q2: Can I replace a different Allanson model with this one?
A: Only if the electrical specifications and grounding type match. Cross-reference before ordering.
Q3: How do I know if my transformer is failing?
A: Common signs include intermittent ignition, frequent reset trips, or no spark at the electrodes.
Q4: Is this transformer universal?
A: No, it is application-specific. Always match voltage, frequency, and grounding type to your burner requirements.
