Flame rollout switches are mounted around your burners. They exist to sense when/if the flame were ever to pose a risk to the homeowner.
These are usually bimetal switches that warp when heated to break the heat cycle when they sense a flame rollout situation. They’re traditionally manually reset by pressing the button in the middle, although some use a heat-activated fuse which would mean you’d need to replace the whole part if it were ever to sense rollout.
A few common causes of a tripped flame roll-out limit are:
- Blocked exhaust
- Blocked combustion air
- Plugged heat exchanger
- Cracked heat exchanger