The inclusion of the internal check valve facilitates bi-flow operation

and gaskets to eliminate internal bypass and improve valve reliability

An open circuit (infinite resistance) indicates the element has failed

The unit is integrated into the boiler safety circuit

some technicians use these in retrofit scenarios

McDonnell & Miller 94-A Pump Controller R-22 The inclusion of the internalThe 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