The EN121371F ELITE Aquastat Well is a premium 3/4" NPT stainless steel immersion well engineered for strength, corrosion resistance, and long-lasting performance. Designed as a direct replacement for Honeywell 121371F, this well ensures accurate temperature sensing and reliable operation in hydronic heating systems.
✅ Key Features
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Direct replacement for Honeywell 121371F aquastat well
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3/4" NPT threaded connection for secure installation
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Heavy-duty stainless steel build for corrosion resistance & durability
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Precision design ensures proper bulb placement and stable readings
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Long service life in residential & commercial hydronic systems
📊 Technical Specifications
| Feature | Details |
|---|
| Product Code |
EN121371F |
| Product Type |
Aquastat Well |
| Connection Size |
3/4" NPT |
| Material |
Stainless Steel |
| OEM Replacement |
Honeywell 121371F |
| Application |
Hydronic heating systems |
⚙️ Common Symptoms of a Bad Aquastat Well
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Visible scaling, rust, or corrosion inside the well
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Aquastat bulb doesn’t fit securely or shifts position
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Inaccurate or fluctuating temperature readings
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System short-cycling or performance issues
🔄 Quick Reference Compatibility
❓ Frequently Asked Questions (FAQ)
Q: What’s the difference between the EN121371E and EN121371F?
A: Both are stainless steel aquastat wells — the E is 1/2" NPT, while the F is 3/4" NPT.
Q: Does this come with a clamp assembly?
A: No — clamp assemblies are sold separately.
Q: Is stainless steel better than copper?
A: Stainless steel provides enhanced corrosion resistance, making it ideal for systems with aggressive water conditions.
Q: Can I use this in both residential and commercial systems?
A: Yes, it’s designed for both small-scale and high-demand heating applications.
🔧 Aquastat Well Comparison Chart (Elite Series – Honeywell Replacements)
| Product Code | OEM Replacement | Connection Size | Insertion Length | Insulation Depth | Material | Bulb Size | Notes |
|---|
| EN121371A |
Honeywell 121371A |
1/2" NPT |
3" (7.6 cm) |
1-1/2" |
Copper |
3/8" × 3" |
Compact copper well, reliable thermal transfer |
| EN121371B |
Honeywell 121371B |
3/4" NPT |
3" (7.6 cm) |
1-1/2" |
Copper |
3/8" × 3" |
Standard copper build for hydronic systems |
| EN121371E |
Honeywell 121371E |
1/2" NPT |
3" (7.6 cm) |
1/2" |
Stainless Steel |
3/8" × 3" |
Corrosion-resistant SS for aggressive water |
| EN121371F |
Honeywell 121371F |
3/4" NPT |
3" (7.6 cm) |
3/4" |
Stainless Steel |
3/8" × 3" |
Heavy-duty SS, ideal for residential & commercial |
| EN121371M |
Honeywell 121371M |
3/4" NPT |
3" (7.6 cm) |
3" |
Copper |
3/8" × 3" |
Extended insulation for added efficiency |
