普通アメリカボイラー形態
<iframe width="1280" height="720" src="https://www.youtube.com/embed/AQD_MedIklI" title="How a Furnace Works - Furnace Sequence of Operation" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe>
<iframe width="1280" height="720" src="https://www.youtube.com/embed/q7Kh2WwkSfQ" title="Furnace Won’t Turn On? Here Are 5 Easy Things To Check" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe>
