dielectric connections
Introduction to Water Heater Piping Connections
In this lesson, we focus on the water piping connections specifically associated with water heaters. The following points outline the importance of these connections and the methods used to ensure longevity and functionality of water heaters.
Importance of Proper Connections
Dielectric Connections
The key type of connection discussed is the dielectric connection. The primary purpose of these fittings is to protect the water heater tank from rust and corrosion.
Rust and Corrosion
Corrosion within the tank is often attributed to dissimilar metals connected to the tank, leading to a process known as electrolysis. When metals such as copper or brass are connected to a steel tank, it creates a scenario where corrosion occurs due to the connection between dissimilar metals. This connection can lead to the tank's failure over time even when it features a glass lining.
Failure Points
It should be noted that the threaded portion of the tank, where the piping connections are made, is typically made of raw galvanized steel, which invites concerns over corrosion. The explanation of electrolysis is crucial here; when there is close proximity between these differing metals, a slight electric potential arises, promoting corrosion, particularly affecting steel.
Types of Flexible Connectors
Several types of flexible connectors are available, each with its unique attributes:
Copper Flexible Connectors
A common type is the copper flexible connector with brass ends. It includes:
A rubber washer inside that prevents direct contact between the copper material and the steel nipple at the water heater's top.
Stainless Steel Connectors
Stainless Steel Corrugated Connector: This connector is characterized by its durability and resistance to cracking compared to copper connectors, making it a long-lasting option.
Braided Stainless Steel Flexible Connector: This option sometimes features a smaller internal diameter compared to the pipe size, potentially leading to a pressure drop during use.
Dielectric Unions
The fittings referred to as dielectric unions consist of a male and female component, each designed for specific connections:
The male threaded connection fits into the tank, while the female threaded connection allows for a connection with the piping. This differentiation is essential for understanding how to utilize these unions properly.
Installation Considerations
Some water heater manufacturers may provide nipples on their units, while others do not. If there are no nipples:
The male dielectric union must be threaded directly into the tank.
If nipples are present, the female dielectric union fits comfortably atop them.
Composition and Protection
A typical dielectric union involves:
Galvanized threads on one side.
A soldered copper connection on the opposite side, with protective measures in place:
A plastic sleeve prevents copper from contacting galvanized steel.
A rubber washer prevents copper from direct contact with steel, ensuring a true dielectric connection.
Maintenance Warning
It is essential not to over-tighten the nut on the dielectric union, as this may excessively compress the rubber washer, leading to wear or failure. Some common maintenance issues involve:
Rubber washers becoming worn out or corroded, requiring regular checks and potential replacement.
However, supply houses often do not sell individual washers for dielectric unions, necessitating the purchase of entirely new unions instead.
Advantages of Plastic Lined Nipples
Plastic lined nipples are increasingly provided by manufacturers and are beneficial due to:
Their resistance to rust, eliminating common service issues where rust would restrict water flow in and out of the heater.
The internal structure that prevents the buildup of rust inside, effectively solving prevalent problems associated with corrosion.
Conclusion
This session has covered the vital aspects of water heater piping connections, emphasizing dielectric connections' role in combating rust and corrosion. Understanding these components is critical for maintaining water heater efficiency and longevity. We will delve deeper into the topic in the next lesson.