Hello,
I am posting in the general forum, because my questions can apply across many brands. Move it to the Shaver Forum if needed.
I removed all of the exterior metal siding from my Shaver 165 wood boiler last week. I have had it in service 10 years. I decided I needed to check for leaks, insulation condition, and water tank rust. I did not find any leaks, but did find rust. It has been about 3-4 years since I took off the roof sheet metal to inspect the interior of the water tank, thus resealing with RTV sealant. (And I will testify this is the only way to make sure the RTV is completely sealing the plate!)
After peeling off the insulation, I discovered the top metal of the water tank was rusted severely. I removed the rust scale with a prybar fork as best as I could. No holes as I can see. I then treated the water tank exterior with Ospho, which chemically kills the rust, turning it black. I think it was caused by the leaking RTV seal on the cover plate, which allowed the insulation to get and stay wet.
I have an old farmhouse built in 1917, which has had about all of the upgrades that can be made to make it more energy efficient. i.e. R32 attic insulation, drop ceilings to 8' from 10', R-19 in floors, storm windows, blower door test / replaced leaky forced air duct work, weather calking everywhere imaginable. Total living space around 1800 sq. ft.
I live in North Arkansas where the average winter hi/low temperature is between 26 and 50 degrees. I average burning 7 - 8 cords per year. To compare, I averaged 800-1000 gallons of propane the last 2 years I exclusively used it. I mostly buy my wood. We like our house around 76 degrees F in the winter. I fire my boiler at 150 max, but will raise it to 160 in below freezing temps.
I made the fan damper and drywell Ranco thermostat modifications the second year in service. Absolutely a necessity. Last week I took the burn chamber / ash doors to a machine shop to weld a 3/4" track around the perimeters so I can install a rope gasket on each. I tried using a rope gasket before, but it would not stay in place after a few weeks of use. The track will give more surface for the adhesive to hold it in place.
I also just re plumbed the hot water coil to split the cold water supply on the hot water heater, forcing the cold water to circulate through the boiler coil before entering the hot water tank's cold water pipe. The setup has ball valves to allow the loop to be closed off when the boiler is not fired. I may need a mixing valve here to prevent scalding. I have not used the water coil the last two years, as my Armstrong circulating pump quit working.
My main question is for replacing insulation. I see pictures on the web of various brands with what appears to be 8-10" of batts surrounding the water tank. The Shaver had maybe 2", with the reflective radiant foil on one side. The bottom was not insulated. There were 6" fiberglass un-faced batts on the top, with the radiant foil overlaid on top of the fiberglass.
Would I save fire wood by adding 2" x 2" stringers on top of the skin frame, and insulating with 6" of fiberglass batts on the side walls? Or would Polyisocyanurate Rigid Foam Insulation Board work better? Will the 180 degree water melt it? Is the foil radiant barrier on top give much help in retaining heat? Any other suggestions on better efficiency?
Sorry about the rambling on before getting to my question.
Thanks
Jerry