The McDonnell & Miller 94-A Pump Controller (Part Number 165500) is a heavy-duty combination low water cut-off and liquid level control engineered specifically for commercial and industrial steam boilers. Rated for a maximum pressure of 250 PSI, this float-operated unit provides reliable burner protection and automatic feed pump cycling to maintain consistent water levels regardless of steaming capacity. Unlike standard models, the 94-A features 1-1/4" NPT alternate tappings, offering contractors greater flexibility during field piping and installations involving separate water columns or specialized manifold configurations. This controller utilizes a high-reliability magnetic repulsion mechanism that eliminates the need for bellows, reducing potential fail points in high-pressure environments. The internal Number 5 switch assembly consists of two snap-acting SPDT switches, ensuring precise electrical signaling for both the burner circuit and the pump starter. Designed for use as a primary or secondary LWCO, the 10-bolt flange design allows for easy head mechanism removal and maintenance without disturbing the boiler piping connections, making it the preferred choice for veteran technicians managing high-pressure steam systems. Key Benefits Enhanced Versatility: Equipped with 1-1/4" NPT alternate tappings for simplified installation on diverse boiler configurations. Durable Operation: Uses magnetic repulsion technology to eliminate mechanical bellows, extending service life in 250 PSI applications. Dual-Function Control: Integrated low water cut-off and pump controller reduces the need for multiple boiler penetrations. Precise Switching: Features durable snap-acting SPDT switches for consistent electrical performance under heavy industrial loads. Serviceable Design: Large 10-bolt flange allows for rapid inspection and internal component replacement to minimize system downtime. Common Questions What is the difference between the 94 and the 94-A? The McDonnell & Miller 94-A includes 1-1/4" NPT alternate tappings located on the side of the casting, providing additional piping options that the standard Series 94 does not offer. Can this be used on high-pressure steam boilers? Yes, this unit is specifically rated for high-pressure steam systems up to a maximum operating pressure of 250 PSI (17.6 kg/cm2). Does this unit require a manual reset? This specific model (165500) features automatic reset functionality. If a manual reset is required by local code, you would need the 94-AM variant. This item is not eligible for free shipping. 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.
