Micro Minnie 2108DS water heater problem

[Morich]

What I have run into on the thermal things is when I got mud daubers in the vents and that stopped air from going in and sucking the heat from the fire on through and out where it was supposed to go. With the vent blocked, the flame and heat came back out right below the thermal cutoff, melted it and everything shut down as it should to stop fire.
I think about every place has some type bug or animal of some type to ruin our day, but it may be worthwhile to stick a vac on the tube and see if it seems to let air pass. You may know history better but those little buggers seem to love to follow me around and they seem to build quicker than I can tear them down if I don't put screens over the furnace and any other vents I can find!

I have no real proof but I might guess that the heat might run up that short distance if the wind was blowing the wrong way? That 208 degrees might not be much if we think about holding our hand off a campfire?
Any experience with coal oil lamps? OUCH!
The flame from a water heater is lots bigger, so it might not take all that much to melt the tiny little thing!

 

[Morich]

On the question of the other parts, I would want to take a look but I would guess that there would be several small parts that do different things and all would need to be right. The thermostat is certain to be one that sense the water temp and has to close to pass current to the heating element, then when it reaching the high temp, it has to open to turn that current off. With the thermal cutoff directly in line with the thermostat, I'm sure both of them have to be closed to get power to the heater. With power from one needing to go through the other, either the thermostat opening when it finds the water hot enough OR the thermal melting when things get too hot in the spot will both shut down both electric or propane heating.
The thermostat opens and closes normally but the thermal is there as a safety to shut it all down when things get so hot it melts!

 

[IdahoHunter]

What I have run into on the thermal things is when I got mud daubers in the vents and that stopped air from going in and sucking the heat from the fire on through and out where it was supposed to go. With the vent blocked, the flame and heat came back out right below the thermal cutoff, melted it and everything shut down as it should to stop fire.
I think about every place has some type bug or animal of some type to ruin our day, but it may be worthwhile to stick a vac on the tube and see if it seems to let air pass. You may know history better but those little buggers seem to love to follow me around and they seem to build quicker than I can tear them down if I don't put screens over the furnace and any other vents I can find!

I have no real proof but I might guess that the heat might run up that short distance if the wind was blowing the wrong way? That 208 degrees might not be much if we think about holding our hand off a campfire?
Any experience with coal oil lamps? OUCH!
The flame from a water heater is lots bigger, so it might not take all that much to melt the tiny little thing!

Good ideas. Tks. I did a pretty good visual, but I could be more thorough than that.....like with a vacuum. Interesting to read your comment about wind, because I wondered about that since on the outing before the failure, we did have some wind and rain the night before we left camp. So, I too was wondering if the wind could come at an angle to cause a swirl to "pull" some fire out of the combustion tube.

The best thing that came out of this is learning more about my trailer, which makes me more prepared to handle problems. No different than fixing any other problem around the house, in my vehicles, etc.

 

[Morich]

One to keep in mind!
And when we look at that little group of parts, it does make me feel better that we get the advantages of things that the builders have learned over a long history!
I'm sure that there were a few RV burned when the thermostat stuck and there was no little gizmo to melt and shut it all down.
And that is one to be aware of if you find that thermo item is melted and open. Since it doesn't carry the big current it takes to heat water, we have to ask why we find it melted??
Was the thermostat getting burned contacts that were sticking some of the time and then finally did stick so the heat finally got hot enough to melt the thermo?
So when we find that one small part melted, we need to be more aware and watch for a failing thermostat, restricted vent or something else, maybe?
One of the big things on repair is figuring out why we have to do it that time, so we don't have to do it again!
A small point can be watching, but standing back a bit while the water heater lights! If it is all working as it should the fire should stay well inside the burn tube. But if we light it and fire seems to come rolling out and lots of heat goes up across the thermo, we may need to find a problem. Something needs adjustment or cleaning if the fire is not staying where it should!

We sometimes read about the water heater or furnace melting the side of the RV? That's a good sign things need help, even if we have to pay somebody to fix it!

 

[Wmlunt-WO]

I sure hope so… that is not a thermal fuse, but over current fuse, likely a short to ground would pull high current. If not plugged in to shore power the trailer ground is floating, yikes!
Bill

Wow, never seen a thermal trip not in contact, and from the pic doesn’t seem to show it in the gas heat path. Live and learn.