McDonnell & Miller 150S-HD Head Mechanism 173003 For 150

Original price was: $1,163.89.Current price is: $797.63.

3 in stock

SKU: 82162 Category:


The McDonnell & Miller 150S-HD Head Mechanism is a replacement part for Series 150S and Series 157S Low Water Cut-Off (LWCO) units in steam boilers. Its primary function is to quickly and easily replace the vital components of the LWCO without disrupting existing piping or boiler operation. Here’s a breakdown of its key features and benefits:


  • Fast and efficient replacement: Allows you to swap out the head mechanism of your Series 150S or 157S LWCO without disconnecting boiler piping or draining the system, minimizing downtime and labor costs.
  • Houses vital components: Contains the float chamber, snap-action switches, and external connections that are crucial for the LWCO’s operation.
  • Safety and protection: Ensures your boiler is protected from the dangers of low water conditions by automatically shutting down the burner when water levels fall below a safe threshold.


  • Simplified maintenance: Enables quick and easy repairs or replacements without complex disassembly or draining, saving time and effort.
  • Reduced disruption: Minimizes downtime for your boiler system, keeping you warm and comfortable with minimal interruption.
  • Cost-effective solution: Replacing the head mechanism is often more cost-efficient than purchasing a whole new LWCO unit.
  • Durable construction: Built with high-quality materials for reliable performance and long-lasting operation.
  • Versatility: Compatible with various models within the Series 150S and 157S range, offering flexibility for different boiler systems.

Things to consider:

  • Compatibility: Ensure the 150S-HD Head Mechanism matches your specific Series 150S or 157S LWCO model and pressure rating.
  • Installation: While potentially doable for DIYers with technical expertise, consulting a qualified boiler technician is recommended for safe and proper installation, especially considering the critical safety function of the LWCO.
  • Limited functionality: Only replaces the head portion, requiring the existing LWCO body and other components to be functional.

Overall, the McDonnell & Miller 150S-HD Head Mechanism is a valuable tool for simplifying maintenance and repairs on Series 150S and 157S LWCOs in steam boilers. Its ease of use, reduced downtime, and compatibility with various models make it a popular choice for boiler owners and technicians looking for a quick, efficient, and cost-effective solution to maintain boiler safety and performance.

Additional information

Weight 11.4 lbs


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