Less than a month ago we swung north around Williston, North Dakota, ably guided by our in-house travel nanny, Ludmilla Andropov. The place is a madhouse of drilling and related activity, so we headed north and then east on a secondary road, stopping for the night at a reservoir campground above the tiny town of McGregor.
We found a nice spot, open to the water, and enjoyed the mild breeze flowing across the reservoir. Planning to stay one night, we hooked up to the power and prepared for dinner.
I was sitting on the lee side of the trailer as Kathy prepared some food. She was cooking something, and I happened to look up and noticed grayish-white smoke coming from the upper refrigerator
vent. Something was afoot, so I asked the cook to shut down the burner and the propane
The smoke kept coming, so I grabbed a Phillips and undid the 14 screws holding the vent cover. Looking in we saw glowing embers under the cook top and above the refrigerator
. The smoke kept coming, so I picked up the fire extinguisher and gave a squirt toward the parts which glowed the most.
The cook top came off, and the pan underneath came off. I was prepared for something to flare up with the easier access to fresh air, but the fire seemed stable in a couple of the wooden edge supports surrounding the pan. A couple of wet paper towels were then draped on the embers which squelched the glowing parts.
With the TV still hooked up the possibilities for total disaster were quite clear, so I started looking at what had happened: First, the pan had at least a half-dozen holes in it, 3 round ones for the propane
hose and a couple of square ones for some unknown purpose. The wood supports around the pan (not touching the pan) were scorched for something like 30 percent of the circumference and in the worst area was reduced to half thickness.
Our usual practice when cooking is to run the exhaust fan at low speed, but this time the pressure from the wind coming into the trailer through the screen door provided plenty of positive pressure into the trailer. The flames on the burner, instead of licking up to do the cooking, were being bent down and driven through the holes and exhausted through the frig vent, setting the supports on fire.
After the scorched parts started to cool down I grabbed the Atwood installation guide and started reading. In the fine print there was a reference to the holes in the pan being sealed up and the whole space under the cooktop also being sealed up. When I installed the replacement counter top years agoI had carelessly duplicated the setup I found originally, thinking nothing of it, and none of that had been considered or modified.
Over the refrigerator
top (under the cook top) was a one and a half inch thick Styrofoam panel for insulation. About 80% of that had disappeared, strangely without any black scorching (melting and sublimation?) and that contributed to the open flow over the refrigerator and out.
After doing a fairly haphazard job of covering the cold embers and the holes in the pan with the aluminized tape I always carry with me I felt it might be safe to use the burner on low heat while watching that the flames always angled up and were not drawn underneath.
It had not occurred to me to try to understand the difference between "sealed" and "not sealed" burners, but this episode got my attention. "Sealed" burners have no air path to the underside of the cook top, and as you can see from the pictures, the Atwood has plenty of space around the orifices for air, gas, or flames to be drawn down.
These burners are probably mostly safe IF there is no path for air, etc. to be drawn down, but it means that the pan and the space below must be completely sealed so that no positive pressure can force flames down, a tall order considering the reputation some installers have for ignoring the cautions from the manufacturers. Creating negative pressure inside is likely a prudent idea.
Cook top replacement was a ways down on my priority list, given that the burners seemed to work pretty well. From one of the pictures you will see how the edge of the counter top looks scorched along the front edge, and this has been the case for many years. I attributed this to food stains, but when I consider what I found it seems obvious that this was not the first time this scorching had happened but in fact a process over many years. The nice breeze straight through the screen door apparently brought the fire to a new level of intensity.
A new cook top seemed in order, so I now have one with sealed burners almost installed, and I plan to use some amorphous silicate fabric lining (used in automotive heat shielding applications and available from Amazon, et al) for extra insurance this time.
Considering the possibly disastrous outcome of this episode I would suggest that if you have a cook top that is not sealed and could have an air path through the unit to the outside to run a quick test: close all the windows
and vents, turn on a burner, then watch how the flames behave when you close the door quickly. If they suddenly bend down it may be time to consider some remedial work.