McDonnell & Miller 344300 Shield Assembly

The McDonnell & Miller 344300 Shield Assembly, recognized as Model SA69-104, is a critical replacement component engineered for the 69 Series Low Water Cut-Off (LWCO). Designed specifically for steam boiler applications, this assembly provides a protective surround for the float, safeguarding internal mechanisms against scale buildup and turbulent water conditions that could lead to nuisance tripping. For technicians servicing float-type controls, maintaining the integrity of the shield assembly is essential to ensure accurate liquid level sensing and boiler safety.

This OEM part is compatible with a wide range of hardware, including Model 69, 69-J, 169, 269, and 369 variants. It is often installed alongside the 6667 head mechanism to restore factory-spec operation. Built to withstand industrial-grade thermal stress, the SA69-104 facilitates proper boiler control maintenance by protecting the sensitive bellows and float from debris. When performing as part of a low water cut-off repair kit, it helps prevent dry-fire conditions, ensuring the system remains compliant and operational in demanding hydronic environments.

• Enhanced Component Protection: Minimizes the impact of sediment and scale on the float mechanism to prevent premature failure.
• Broad Compatibility: Direct fit for multiple 69 Series models, including the 169, 269, 369, 469, and 569 configurations.
• Increased System Stability: Dampens the effects of boiler surging and water level fluctuations for consistent LWCO performance.
• Durable Construction: Heavy-duty materials designed to handle the high-pressure environment of steam boiler systems.

What models are compatible with the McDonnell & Miller 344300?
This shield assembly is designed for the 69 Series, including specialized versions like the 69-MV-P and the 369-MV millivolt models.

Does this assembly include the o-rings and gaskets?
The SA69-104 is typically evaluated as the shield component. For a complete seal, technicians should verify the condition of the 69-113 and 69-114 o-rings during installation.

Why is the shield assembly necessary for a float-type LWCO?
Without a proper shield, the float can become fouled by debris or erratic water movement, which compromises the low water cut-off's ability to safely shut down the burner.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.