EN121371M ELITE 3/4" NPT Aquastat Well – 3" Insertion, 3" Insulation (For Honeywell 121371M)

The EN121371M ELITE Aquastat Well is a precision copper immersion well designed as a direct replacement for the Honeywell 121371M. With a 3/4" NPT connection, 3" insertion length, and extended 3" insulation, this well ensures reliable aquastat sensor placement and dependable performance in hydronic heating systems.

⚠️ Note: Well Clamp Assembly is sold separately and not included.

✅ Key Features

• Direct replacement for Honeywell 121371M aquastat well

• 3/4" NPT threaded connection for secure installation

• 3" insertion length for accurate sensor positioning

• Extended 3" insulation for added system efficiency

• Copper construction for excellent heat transfer and durability

• Compatible with 3/8" x 3" bulb size

📊 Technical Specifications

⚙️ Common Symptoms of a Bad Aquastat Well

• Sensor does not sit securely or shifts inside the well

• Inaccurate or fluctuating temperature readings

• Insulation deterioration causing poor efficiency

• Corrosion, scaling, or leaks around the well

🔄 Quick Reference Compatibility

• Honeywell 121371M (direct OEM replacement)

• Hydronic heating systems requiring a 3/4" NPT, 3" insertion copper immersion well with 3" insulation

❓ Frequently Asked Questions (FAQ)

Q: How is the EN121371M different from the EN121371B?
A: Both are copper 3/4" NPT wells, but the M model has extended 3" insulation, while the B has 1-1/2" insulation.

Q: Can I use this well for any 3/4" NPT system?
A: Yes, as long as the system requires a 3/4" NPT aquastat well with 3" insertion length and 3" insulation depth.

Q: Does it come with the clamp assembly?
A: No, the clamp assembly is sold separately.

Q: Why is copper preferred for this model?
A: Copper offers excellent thermal conductivity, ensuring accurate aquastat response times.

🔧 Aquastat Well Comparison Chart (Elite Series – Honeywell Replacements)