单选

Excessive vibration of an automatically fired auxiliary boiler can be caused by _____.

  • A.air or water in the furnace
  • B.combustion pulses
  • C.fuel oil pump failure
  • D.flame failure
参考答案
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Excessive vibration of an automatically fired auxiliary boiler can be caused by _____.

  • A.air or water in the furnace
  • B.combustion pulses
  • C.fuel oil pump failure
  • D.flame failure
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