McDonnell & Miller 344200 Float and Bellows Assembly

When you are out in the field servicing a customer's boiler, a compromised level control is a leading cause of nuisance outages and dangerous dry-firing conditions. The McDonnell & Miller 344200 Float and Bellows Assembly (Model SA67-2) is the direct manufacturer-spec replacement for Series 61, Series 67, Series 69, and Series 70 low water cut-offs. This critical assembly is precision-engineered to maintain accurate water level detection and interface with the LWCO burner circuit to ensure safe equipment operation. Unlike generic components, this genuine McDonnell & Miller replacement part features a high-tensile bellows cup designed to withstand the thermal cycling and pressure fluctuations common in steam and hot water boilers. The SA67-2 assembly integrates seamlessly into the head casting, providing a reliable mechanical link to the switch mechanism. Using authentic boiler control parts eliminates the risk of misalignment or binding that often occurs with aftermarket alternates, ensuring your service call results in a long-term fix rather than a callback.

• Universal Compatibility: Specifically designed for broad application across M&M 61, 67, 69, 70, and 767 Series units.
• Precision Level Detection: Ensures the low water cut-off trips at the exact factory-calibrated set point to prevent heat exchanger damage.
• Industrial-Grade Bellows: Resists sediment buildup and scale accumulation within the corrugations for longer service intervals.
• Streamlined Installation: Designed for an exact fit, reducing labor time during annual boiler inspections and repairs.

Is the gasket included with the SA67-2 assembly?
Typically, the float and bellows assembly is sold as a standalone mechanical component. It is standard practice for technicians to replace the flange gasket simultaneously to ensure a pressure-tight seal.

Which specific models does the 344200 repair?
This assembly is the correct repair part for Models 61, 67, 67-G, 67-LQHU, 69, 69-MV-P, 369, and 767. Always verify the series number on the existing nameplate before installation.

What causes bellows failure in these units?
The most common causes include heavy scale buildup from poor water quality or aggressive chemical treatments that compromise the spring steel. Regular blow-downs are recommended to maintain optimal LWCO performance.

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.