EN121371B ELITE 3/4" NPT Aquastat Well – 3" Insertion, 1-1/2" Insulation (Replacement for Honeywell 121371B)
The EN121371B ELITE Aquastat Well is a precision-engineered copper immersion well designed for hydronic heating systems. Built as a direct replacement for Honeywell 121371B, this well provides accurate bulb placement and dependable thermal transfer for optimal system control and performance.
⚠️ Note: Well Clamp Assembly is sold separately and not included.
✅ Key Features
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Direct replacement for Honeywell 121371B aquastat well
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3/4" NPT threaded connection for secure installation
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3" insertion length for accurate sensor positioning
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Durable copper construction for long-lasting performance
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1-1/2" insulation depth with 5/64" capillary diameter
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Compatible with standard 3/8" x 3" bulb size
📊 Technical Specifications
| Feature | Details |
|---|
| Product Code |
EN121371B |
| Connection Size |
3/4" NPT |
| Insertion Length |
3" |
| Shell I.D. |
3/8" |
| Bulb Size |
3/8" x 3" |
| Insulation |
1-1/2" |
| Capillary Diameter |
5/64" |
| Material |
Copper |
| OEM Replacement |
Honeywell 121371B |
⚙️ Common Symptoms of a Bad Aquastat Well
If your aquastat well is failing, you may notice:
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Inaccurate or fluctuating temperature readings
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Poor system response or cycling issues
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Visible corrosion, leaks, or damage around the well
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Difficulty inserting or securing the bulb properly
🔄 Quick Reference Compatibility
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Honeywell 121371B (Direct OEM replacement)
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Fits hydronic heating systems requiring 3/4" NPT, 3" insertion, 1-1/2" insulation
❓ Frequently Asked Questions (FAQ)
Q: Is the clamp assembly included?
A: No, the clamp assembly is sold separately.
Q: What size bulb fits this well?
A: It is designed for 3/8" x 3" bulbs.
Q: What’s the benefit of copper construction?
A: Copper ensures excellent thermal conductivity and durability in heating systems.
Q: How do I know if this will fit my system?
A: Check your OEM part number (121371B) or confirm system requirements for 3/4" NPT, 3" insertion.
