How is the admission of steam to the coils of a domestic hot water supply tank regulated?

• A. By a manual control valve
• B. By a thermostatic control valve
• C. By a pressure relief valve
• D. By an automatic shut-off valve

Answer: (B)

The admission of steam to the coils of a domestic hot water supply tank is primarily regulated by a thermostatic control valve. This type of valve operates based on the temperature of the water within the tank. When the water temperature drops below a set point, the thermostatic control valve opens, allowing steam to flow into the coils and heat the water. As the temperature rises to the desired level, the valve closes to prevent further steam from entering the system. This mechanism ensures that the water is consistently maintained at the set temperature, optimizing energy efficiency and comfort for the end user. The use of a thermostatic control valve is particularly important in maintaining the right balance and preventing overheating or underheating of the water supply.