A couple of months ago I asked this question regarding my natural gas furnace that is used to heat my house via baseboard/water heating.
It seemed to have quit working, but I called the repairman. The repairman spent less than 5 minutes in my home and just pointed out that there is an upside down button I can press to reset it. This consultation cost me $300.
Pressing the button works fine, except that I have to press it 5+ times per day, now that it is getting cold and snowing. I need to find a somewhat better fix, but I definitely do not have the $ for the repairman to come back.
I forget exactly how he explained it, but basically I think he said there's some cut-off in the hood that is getting mistakenly tripped. I think he suggested that the next step would be to clean, repair, or replace some part of that to prevent it from cutting off.
Given that it's cold and I don't have the money for professional repairs, is there some sort of temporary way to keep the furnace from mistakenly shutting off?
Stack Exchange is rotating that 2nd photo on me, it seems. For more photos please see the link above.
Best Answer
Blocked flue and/or insufficient combustion air inlets.
Charging $300 without at least giving you a complete understanding of the problem was pretty lame.
That looks like the flue rollout sensor. If that is what is tripping, then you might have a blocked flue. Verify that the damper above that opens fully when the boiler turns on. Does it? Also check the combustion vent outside and make sure there's no obstruction like a bird's nest. Turn the water heater to pilot, turn off the furnace, remove the flue cap outside and inspect it with a flashlight. The button is on the bottom of the rollout sensor I presume (I cannot really see it).
If the flue damper does not open correctly then disconnect the actuator and manually lock it in the open position. Doing that will hurt efficiency a little, but the boiler will run.
The other obvious thing to check is combustion air inlets. I see no outside air inlets in the photo. There needs to be significant airflow into the room from outside to supply combustion and flow out through the flue. If the room is sealed tightly from the outdoors then that is a problem.