It seems I've never seen this kind before. Is it a gas water heater.

我好像以前从未见过这个样子，这是燃气热水器还是电加热热水器呢？

The article also explains design calculation method of gas water heater.

并对燃气热水器的设计计算方法进行了论述。

The use of gas water heater safety problem has been our most important question.

而燃气热水器的运用安全疑问一直是我们最重视的疑问。

An initial investigation showed a gas water heater could have caused the accident.

经警方初步调查，死亡原因疑为热水器煤气中毒。

The thermal balance and thermal efficiency of domestic gas water heater are analyzed.

对家用燃气热水器的热平衡及热效率进行分析。