Just my personal experience here so please don't shoot me if it seems odd.
We got a MF5000e last year. Located in Ohio the house is a brick 2800sq ft with dhw. We started the stove and quickly learned that it only took between 4-7 pieces of wood to last 12 hours depending on the temps (burning cherry and oak pieces of 8-10" dia) This proved more efficient than "filling" the stove and seemed to save wood. The stove started dripping water out of the ash door almost immediately. I work in the tech support business for Fujifilm and started a K-T problem solving sequence-try to identify the root cause and eliminate it. Finding the root cause is difficult when you are not a stove tech so experimenting was the next step.
It was thought that the wood was too wet and the water was condensation. We were burning wood that was down for 2 years but only cut and split for 6 months. We had done some remodeling and had a bunch of scrap wood so the test was to burn 40 year old dry 2x4 and 2x6 pine for 3 days with no "seasoned wood". Issue remained- Wet wood not the cause.
The air intake was changed from 100% to 20% in 2-3 day increments-no significant change.
I had been burning wood since the 70's and thought this should be easy but grasping for straws wasn't getting anywhere so I started reading and researching.
The on/off point was changed to higher and lower temps for 2/3 days at each test. 160-170, 170-180, 175-185. 180-185. The thought was that the stove idled too long at too low of an internal temp and the air leaks were exaggerated. Trying to keep the stove needing heat was the goal. lower temp would require that the fan on my furnace would run longer to heat the house to the same temp. This would cause the stove to run more frequently and also not go out. A 5 degree differential might accomplish the same thing. All offered no improvement.
Research suggested air leak- Cold moist air coming in around rope gaskets could meet hot dry air and condense at point of contact. Gaskets were repositioned and doors and latches readjusted to minimize air leaks. (The ash door gasket gets pushed to the side due to the ash pan resting on the bottom of the channel that it rests on. It should be centered better but that would take some redesigning). This appeared to provide some relief however never completely stopped the phenomenon.
As this experimenting went on the stove started going out during the day after about 2 months of working fine. I was ready to pull the stove out! My dealer was great to work with and called me about every other day to check on my progress. He offered to come out and check it out but I declined. Stubborn...Proud....Stupid....lol. Our house is pretty well insulated and didn't really need too much help maintaining heat. One of the main symptoms was that when we opened the door to check or fill the stove there was no pile of coals in the fire box. All that was left were the pieces of charred wood. On top of that the ash pan was filled with 1/4" to 1/2" chunks of charcoal-no ash. The thought was that the fan was blowing the fire out and I left the ash pan full for longer periods and it improved the fire going out but still had water dripping out of the ash pan. Working with my dealer and Woodmaster we checked other items that offered no help to the sweating but improved the fire going out some.
About this time it got to -20F outside and I was going to be gone for the week leaving my 110# wife to tend the stove. We decided to forget about saving wood and had her fill the stove as full as she could get it so that it wouldn't go out on her. After a week of doing this I returned home to find about 6-8" of coals in the bottom of the fire box. On top of that the ash pan was only 1/4 full after a full week of heavy burning. Hmmmm. We then went back to putting just enough wood to maintain a 12 hour burn and keep the same amount of coals in the fire box. Back to 6-8 medium pieces of wood per load and the coals stayed and the dripping stopped and never came back. This easily lasted 12+ hours.
Through all this a guy looks at the input and the results while taking in subtle clues along the way that may go unnoticed if not paying attention. Through this all I can do is speculate what was the cause and repair. It appears that our lack of need for heat caused the stove to run infrequently. When it would burn it would do so feverishly and the water temp would recover quickly and thus no coals/ash generated. On top of that, our desire to save wood led to fewer pieces of wood in the box from which to burn. When the fan would come on it appeared to blow all the particles that might accumulate in the box down into the ash pan. I never touch the shaker grates. While all this happened the stove was leaking water from the ash pan at up to a cup a day filling a 5 gallon tub 1/2 full of water in a week. Once the firebox was full of coals and stayed that way, the water stopped even though we used wood that I know was wetter than previously used wood.
I know what stopped the issue, however don't know the root cause. Were the coals insulating the doors and gaskets from the air leaks? I'll probably never know but when I fire it up in the fall it'll burn like a mad man until I get a good bed of coals-that's one thing for sure.
Author
Topic: Sweating stove (Read 8162 times)