Expansion Tank
An expansion tank is a safety device used in plumbing systems, especially in water heaters and boiler systems. It's like a safety balloon that gives hot water a place to go when it expands. When water is heated, it needs more space, and without an expansion tank, this could cause dangerous pressure buildup in pipes. Plumbers install these tanks to prevent damage to pipes, fittings, and water heaters. You might also hear it called a 'thermal expansion tank' or 'water heater expansion tank' - they're all the same thing. This is an essential skill for plumbers working on residential and commercial water heating systems.
Examples in Resumes
Installed and maintained Expansion Tanks on residential water heater systems
Diagnosed and replaced faulty Expansion Tanks and Thermal Expansion Tanks in commercial buildings
Performed routine inspections of Water Heater Expansion Tanks and water pressure systems
Typical job title: "Plumbers"
Also try searching for:
Where to Find Plumbers
Professional Organizations
Online Communities
Job Boards
Example Interview Questions
Senior Level Questions
Q: How do you size an expansion tank for a large commercial building?
Expected Answer: A senior plumber should explain the factors involved: building size, water heater capacity, water pressure, and temperature settings. They should mention calculating system volume and using manufacturer sizing charts.
Q: What troubleshooting steps do you take when dealing with a waterlogged expansion tank?
Expected Answer: Should describe checking the air pressure, testing the tank's bladder, inspecting connected systems, and determining if replacement is needed. Should also mention preventive maintenance practices.
Mid Level Questions
Q: Where should an expansion tank be installed in relation to the water heater?
Expected Answer: Should explain that the tank should be installed on the cold water supply line before it enters the water heater, and discuss proper mounting and support requirements.
Q: How do you determine if an expansion tank is working properly?
Expected Answer: Should describe checking air pressure with a tire gauge, tapping the tank to hear if it's waterlogged, and testing the water pressure in the system.
Junior Level Questions
Q: What is the purpose of an expansion tank?
Expected Answer: Should explain that it provides space for water to expand when heated, preventing pressure buildup in the plumbing system and protecting pipes and fixtures.
Q: What are the basic parts of an expansion tank?
Expected Answer: Should mention the air chamber, rubber bladder/diaphragm, and water connection port, explaining how these parts work together.
Experience Level Indicators
Junior (0-2 years)
- Basic expansion tank installation
- Understanding of water heater systems
- Simple pressure testing
- Basic maintenance and replacement
Mid (2-5 years)
- Complex system troubleshooting
- Proper sizing calculations
- System design and modification
- Commercial installation experience
Senior (5+ years)
- Advanced system design
- Commercial project management
- Team supervision and training
- Complex problem diagnosis
Red Flags to Watch For
- No knowledge of basic water pressure principles
- Unable to explain proper installation locations
- Lack of experience with different tank sizes and applications
- No understanding of safety requirements and building codes
Related Terms
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