Systems & Code第 39 / 110 题
A closed water-supply system (with a backflow preventer or check valve at the meter) has a water heater but no expansion control. As the water heats and expands, what device is required to prevent pressure buildup?
a.A pressure-reducing valve
b.A vacuum breaker
c.A thermal expansion tank
d.A backwater valve
解析
A closed system cannot push expanded hot water back into the main, so a thermal expansion tank (or similar expansion control) is required to absorb the volume increase and prevent the T and P valve from weeping. Water expands roughly 2 to 3 percent between cold and hot, which spikes pressure in a sealed system. The expansion tank is charged to system static pressure.
法律依据: UPC §608.5免费刷完整 110 道题库 — 无需注册。
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