Saving My Central Boiler Outdoor Woodstove
September 24, 2020

I installed my Central Boiler CL5648 outdoor wood furnace back in 2003. I has been a workhorse for over 18 years with only minor repairs like a circulator pump and solenoid.

About two years ago I noticed what looked like dampness at the base pad under the main door. It seemed minor but concerned me. Last season it seemed to be leaking more. In checking the water level it seemed I was putting almost 40 gallons of water in the stove every month or so. The stove holds 380 gallons.

I felt it was time to do an exploratory to see if it was a major leak or not before the upcoming season. 2020 hasn't been a good year. The life expectancy of this type of woodstove is approximately 15 years give or take so I think I got my money's worth.

I removed the outside corner pieces, and carefully removed the sheet metal siding. This was not an easy task. I had to pry up the skirt that hid the 1/4 inch sheet metal screws on the top edge of the sheet metal. I used a Crescent wrench and only pried up enough to slip a small 1/4 inch combination wrench to remove the remaining screws. There was one place I had to cut away the sheet metal from the top left corner of the door to the top edge of the sheet metal.

Once removed I saw what seemed to be water saturated foam. I took a serrated knife like a steak knife and cut away all the foam insulation six inches out from around the door. It was evident that there was heavy moisture at three of the corners of the door. I had to saw a portion of the sheet metal support to access the welds.

I took a scraper and wire brush and removed as much flaked rust all around the door.

I used a hand grinder to deep clean the surface of the welds. In doing so I could see that I aggravated the welds in the corners enough to cause a stream of water to appear.

Once I determined that three of the corners were the problem, I drained the water from the stove completely. I finished scaling all the rust around the leaks.

In doing so it became evident that the welds between the 1/4 inch door housing and the 1/8 inch outside water jacket were not welded completely. In fact I could see a smooth curve in the water jacket possibly where the plasma cut was performed to follow the curve of the door sleeve. See below.

I cleaned up as much as I could around the compromised welds.

I had a professional welding company come out and had them weld and built up 7 layers of weld.

I then filled the stove with water to check for leaks. So far no leaks so I fired up the stove to make sure heat didn't cause any stress cracks and cause any other leakage. So far so good.

I cleaned up the welds and applied a generous coat of high temperature exhaust manifold silicone. Probably not needed but I wasn't going to take any chances.

I scaled any remaining loose rust from the water jacket wall. I generously brushed on three coats of Rustoleum gloss black paint on all cleaned exposed metal.

After everything was dry and cured I used three cans of non-expanding foam and filled in where I removed the compromised old foam.

After firing the stove back up to operating temperature, 180 degrees, I waited a few days to make sure all was good. I put a gallon of Central Boiler rust preventive in the stove too.

I attached the old pieces of sheet metal and sealed any remaining cracks and seams in the sheet metal.

So it looks like I may get a few more years of use out of my woodstove.

P.S. I created this page before going on search engines looking for answers and thus biasing my page. Since doing a search of water leaks I have found that I'm not the only one with woodstove leaks. Fortunately my leak was on the outside water jacket and not the firebox side. I did have a pinhole leak when the stove was first installed and it looked like just a small spot missed during the welding of the firebox. I drilled and threaded a screw into the hole and have never had a problem since.

One thing I was not happy about back in 2003-4 was the nonexistent customer service. At that time all questions and service had to go through the local Central Boiler installer. Here again, almost nonexistent. The business that I got my stove through went out of business as soon as my unit was delivered and I had to finish the installation myself. I had many technical questions but just had to forge ahead myself. Fortunately once everything was working, very little had to be done and it has been maintenance free.


Copyright 2020 Rick C.