Can you explain your knowledge of different types of expansion tanks used in hydronic systems and their sizing requirements?

Sample interview questions: Can you explain your knowledge of different types of expansion tanks used in hydronic systems and their sizing requirements?

Sample answer:

Types of Expansion Tanks for Hydronic Systems:

• Open Expansion Tanks: These are located at the highest point in the system and allow water volume to expand directly into the tank without pressurization. They require constant water level monitoring and makeup water additions, which can be prone to evaporation and air infiltration.

• Closed Expansion Tanks: These are sealed, pressurized vessels that use a diaphragm or bladder to separate the water from a compressed gas cushion. They maintain system pressure and eliminate air infiltration, but require periodic pressure checks and adjustments.

• Potable Water Expansion Tanks: These are similar to closed expansion tanks, but are designed for use with potable water systems. They have a food-safe diaphragm or bladder and meet specific water quality standards.

Sizing Requirements:

Expansion tank sizing is crucial to prevent system damage from pressure surges and water hammer. The required tank volume depends on: