Core TradesQuestion 192 of 700
When a check valve or pressure-reducing valve creates a 'closed' water system, a thermal expansion tank is required PRIMARILY to:
a.Absorb the pressure increase caused by water expanding as it is heated
b.Increase available hot-water volume
c.Filter sediment from the water heater
d.Reduce noise from the water heater burner
Explanation
In a closed system, heated water cannot expand back toward the main, so an expansion tank absorbs the resulting pressure rise and protects the tank and relief valve. It does not add usable hot water, filter sediment, or quiet the burner.
Law Reference: 2025 CA Plumbing Code, Chapter 6 (Water Supply)Practice all 700 questions free — no signup required.
Related questions on this topic
- A 4-inch horizontal building drain runs 48 feet at a minimum slope of 1/8 inch per foot. What is the total fall over that run?
- Why does the plumbing code prohibit the use of an 'S-trap' on a fixture?
- What is the MINIMUM drain size generally required for a water closet (toilet)?
- Under current California requirements, newly constructed dwellings must generally provide:
- Using the all-outdoor two-permanent-opening method at a rate of 1 square inch per 4,000 Btu/hr per opening, what is the MINIMUM net free area of EACH opening for a 100,000 Btu/hr furnace?
- Under the California Energy Code, sealing forced-air duct systems is required PRIMARILY to:
Last reviewed: · editorial process
PrepPass Editorial Team · Verified against California CSLB General Building (B) Trade Examination · How we review