LOW WATER CUT-OFF — Like the pressure control, difficul- ties can be broken down into the mechanical and electrical groups.

The mechanical difficulties can be corrected on the high pres- sure 100 psig motor and pump units in the following manner:

1.Remove the cover and test the free movement of the float valve. If the float valve is in the off or down position, then the float is either punctured or dirt and sediment is encrusted in the float chamber. Both of these problems will involve disassem- bly of the float chamber.

2.Check the electrical contacts to determine if they are defective. Defective mercury tube contacts will cause the boiler to fill high- er than normal. This occurrence will require replacement of the mercury tube.

On low pressure feed units, the mechanical test is best made by cleaning the valve seat beneath the float valve linkage to

WATER FEED MECHANISMS — A common problem in this area is boiler flooding, which may be caused by a defective float or solenoid.

The Low Water Cut-Off must be disassembled to check the float valve. The solenoid can be isolated by disconnecting the union after the solenoid and energizing and de-energizing the solenoid. If water comes out continuously or does not come out at all, then the solenoid is defective.

assure that it is properly seated. If the valve seat is scarred or defective, the entire valve seat must be replaced. Also, if the float valve is in the down or “off” position, it may be punctured or encrusted with dirt and the unit must be disassembled.

On all McDonnell-Miller cut-offs, restrictions in the equalizer column can cause burnt out elements. The cause will appear to be a low water condition. Regular blowdown procedures on the equalizer column as well as the boiler will prevent this occur- rence. Correction of the problem can be made by both removing the plug from the side of the column and opening the Low Water Cut-Off blowdown valves. A snake should be used to clean the vertical and horizontal columns.

The electrical trouble shooting should be checked by referring to the Contactors, Elements and Voltages section.

A defective check valve can cause the pump motor to run continuously or cause loss of water pressure. If the pipe between the check valve and the water supply is hot, boiler water is back- ing up through the check valve and the check valve must be replaced. A defective check valve can also prevent water from entering the boiler.

The coupling between the motor and pump may be loose; the entire pump must be replaced if the coupling is excessively worn.

Limited Warranty:

Please refer to the Chromalox limited warranty applicable to this product at http://www.chromalox.com/customer-service/policies/termsofsale.aspx.

2150 N. RULON WHITE BLVD., OGDEN, UT 84404

Phone: 1-800-368-2493

www.chromalox.com

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Chromalox PQ402-6 service manual Limited Warranty
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PQ402-6 specifications

The Chromalox PQ402-6 is a cutting-edge temperature control system designed to enhance operational efficiency in various industrial applications. This advanced system stands out in the market due to its robust features, innovative technologies, and unique characteristics that make it a preferred choice for temperature regulation needs.

At the heart of the Chromalox PQ402-6 is its precise temperature control capability. It is engineered to deliver accurate temperature readings, ensuring that processes remain within optimal ranges, which is crucial for maintaining product quality and avoiding costly errors. The system utilizes advanced sensing technology that allows for rapid response to temperature fluctuations, guaranteeing consistent performance over time.

One of the defining features of the PQ402-6 is its user-friendly interface. The system is equipped with an intuitive touchscreen display that simplifies operation and provides real-time monitoring. This interface allows operators to easily set parameters, view system performance metrics, and receive alerts for any deviations from predefined settings. This level of visibility aids in proactive maintenance, minimizing downtime in production environments.

Another significant aspect of the PQ402-6 is its versatility. Designed to work seamlessly with a variety of heating elements, such as electric heat elements and steam coils, this system can be adapted to diverse industrial applications ranging from food processing to chemical manufacturing. This flexibility ensures that businesses can implement the PQ402-6 in their existing infrastructure with minimal disruption.

Energy efficiency is also a hallmark of the Chromalox PQ402-6. With its intelligent control algorithms, the system optimizes power consumption by adjusting heating levels based on real-time requirements. This not only reduces operational costs but also aligns with sustainability goals by lowering overall energy usage.

Safety is paramount in any industrial setting, and the PQ402-6 does not compromise on this front. It includes multiple safety features such as over-temperature protection, alarm systems for fault detection, and a robust design that meets rigorous industry standards. These features provide peace of mind to operators and ensure compliance with safety regulations.

In conclusion, the Chromalox PQ402-6 is a state-of-the-art temperature control system characterized by its precise control, user-friendly interface, versatility, energy efficiency, and robust safety features. By integrating these advanced technologies, the PQ402-6 not only enhances operational effectiveness but also supports businesses in achieving their production and sustainability objectives. Whether in manufacturing, food processing, or other industrial applications, it proves to be a reliable solution for meeting temperature management challenges.
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