Furnace Burner
The burner on my furnace is cycling on and off? Also, it seems like a lot of heat is being vented out the side? Anyone have any ideas?
Forum Discussion
Understand how these systems work. The flame in the furnace heats the metal surface of the heat exchanger and then exhaust outside, carrying the Carbon Monoxide, soot, and unburned fuel with it.
The blower takes air from inside the trailer, passes it over the surface of the heat exchanger (On the side opposite the flame area), warming it and then pushing it into the trailer.
The air around the flame and the air that goes into the living space never mix!!
Should the flame be on with no interior air moving over the surface of the heat exchanger, the exchanger will eventually melt. Two safety systems prevent this. The "sail switch" is a paddle in the air flow that checks on how much air the blower is putting out. If there is not enough airflow to protect the heat exchanger, the flame is cut off. The other system is "after run" on the blower. After the thermostat hits the set point and shuts the flame down, the blower continues to run until the surface temperature on the heat exchanger is within the safe range. (Oil or gas fired household furnaces do the same thing.)
As others have said, not knowing what trailer, how cold is it outside, and/or anything else makes it difficult to troubleshoot (if there is actually trouble).
Could it be that it is so cold out and the trailer is so poorly insulated (as many are) that the thermostat is calling for the flame to come back on before the blower finishes the "after run" from the previous cycle?
Too many variables for any more than generalizations.
The blower takes air from inside the trailer, passes it over the surface of the heat exchanger (On the side opposite the flame area), warming it and then pushing it into the trailer.
The air around the flame and the air that goes into the living space never mix!!
Should the flame be on with no interior air moving over the surface of the heat exchanger, the exchanger will eventually melt. Two safety systems prevent this. The "sail switch" is a paddle in the air flow that checks on how much air the blower is putting out. If there is not enough airflow to protect the heat exchanger, the flame is cut off. The other system is "after run" on the blower. After the thermostat hits the set point and shuts the flame down, the blower continues to run until the surface temperature on the heat exchanger is within the safe range. (Oil or gas fired household furnaces do the same thing.)
As others have said, not knowing what trailer, how cold is it outside, and/or anything else makes it difficult to troubleshoot (if there is actually trouble).
Could it be that it is so cold out and the trailer is so poorly insulated (as many are) that the thermostat is calling for the flame to come back on before the blower finishes the "after run" from the previous cycle?
Too many variables for any more than generalizations.
