BULLETIN 45

THERMAL EXPANSION

SYMPTOMS

•Effects are only noticeable after hot water use followed by periods of no water use.

•Relief valve drips during any recovery cycle when no hot or cold water is used.

•Hot water pipes creak while heater is recovering and all valves are closed.

•Tanks or other components of the water supply system fail prematurely.

•A metallic creaking noise might actually be heard in the location of the heater as the pressure is relieved and the stretched tank returns to a natural shape.

•Faucet drips during any recovery cycle when no hot or cold water is used.

•Water surges when a faucet is first opened and then pressure drops.

CAUSE

The water in a water heating system expands when it is heated and increases in volume. Since water will not compress (like air), system designers must include provisions for thermal expansion. (Water in a closed tank at 50 psi, when heated just 10 degrees, will reach a pressure of 250 psi).

Many water supply systems have check valves or backflow preventers at the water meter to prevent any possible contamination of the public water supply by the accidental back-flow of contaminated water into the supply mains. These check valves are often required by code, and some cities are even installing the check valves. They serve a useful purpose. Do not remove them!

The use of pressure reducing valves (PRV) is another cause. PRVs are designed to conserve water and prolong fixture life. Many PRVs also act as very effective check valves. Again, do not remove them!

Water softeners in the system may also act as back-flow preventers.

TEST

Follow these easy steps to diagnose thermal expansion:

•Turn the heater thermostat all the way down, and install a water pressure gauge with dead hand on the drain valve. Open the drain valve, so the gauge reads system pressure.

•Open a hot water tap and allow 15% to 20% of the tanks volume to run out. Shut off the drain valve and make sure that no other fixture in the system, hot or cold, is open. Make sure that outside fixtures, if they are on the same system, are turned off too. Any water leaks or use will make the test meaningless.

•Check the water pressure gauge, and turn the pointer so it lines up with the pressure indicating needle. Turn the thermostat back up to its normal position, so the heater cycles on. Watch the pressure gauge.

•If the system is closed, the pressure will start to climb steadily and rapidly. A small amount of thermal expansion control may be built into the system because of trapped air pockets or a water hammer arrestor. In that case the pressure will increase slightly, hold steady for a short time and then rapidly increase. The temperature and pressure relief valve (T&P) or PRV should open and release water once the pressure reaches the maximum setting on the valve. The valve will close once the pressure falls below the pressure setting of the valve.

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State Industries GPX, GSX, GS6 manual Thermal Expansion, Symptoms
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GPX, GS6, GSX specifications

State Industries offers a range of high-quality residential and commercial water heaters that cater to diverse customer needs. Among their prominent models are the GSX, GS6, and GPX, each equipped with unique features, advanced technologies, and distinct characteristics that enhance their performance and efficiency.

The GSX series is well-known for its energy efficiency and reliability. It utilizes a high-efficiency gas burner to provide fast recovery rates, making it suitable for households with high hot water demand. The GSX water heaters are designed with a Foam Insulation System that minimizes heat loss and maximizes energy conservation. Additionally, their innovative design includes a durable glass-lined tank to prevent corrosion, ensuring long-term performance and extended lifespan.

Moving on to the GS6 model, this water heater is characterized by its user-friendly control features, including an adjustable thermostat that allows for precise temperature settings. The GS6 is built with a robust gas control valve that enhances efficiency and helps maintain consistent water temperature. The model is also designed with an anode rod that minimizes corrosion, prolonging the life of the tank. Its standing pilot light system provides reliable ignition, while its compact design makes it suitable for various installation locations, even in tight spaces.

The GPX series stands out in the market with its advanced technological features and sleek design. It integrates smart technologies designed to monitor and optimize performance. The built-in diagnostics programmable control allows users to track system performance and troubleshoot any potential issues easily. The GPX models also come equipped with a high-efficiency condensing gas burner that maximizes energy use, contributing to reduced utility bills. Furthermore, their stainless steel construction adds to their durability and resistance against rust and corrosion.

In summary, State Industries' GSX, GS6, and GPX models represent innovation in the water heating industry. They incorporate energy-efficient technologies, durable materials, and user-friendly controls, making them reliable choices for both residential and commercial applications. With custom features tailored to meet varied needs, these water heaters uphold State Industries' commitment to quality and customer satisfaction, ensuring that users enjoy consistent hot water while being conscious of energy consumption.
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