A、開大給汽閥、打開高放空、關(guān)閉低點(diǎn)排凝 B、打開高點(diǎn)放空、低點(diǎn)排凝、關(guān)小給汽閥 C、關(guān)小給汽閥、打開低點(diǎn)排凝、關(guān)閉高點(diǎn)放空 D、打開高點(diǎn)放空、低點(diǎn)排凝、防止超壓