| 摘要 |
A method of determining flow through a valve includes determining a first differential pressure across the valve. The valve is bypassed and a second differential pressure is determined across the valve. A flow decision is determined for the valve based on comparison of the first and second differential pressures. A method of testing a relief valve in a reduced pressure backflow preventer assembly includes determining a first differential pressure across an upstream check valve during a no flow condition. The upstream check valve is bypassed for the purpose of opening a relief valve, and a zone vent is opened.
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