Used MF 5000 Heatmaster outside boiler for sale. Heats up to 5000 square feet. We went through it and filled it up with water. No leaks. Looks like it's in good condition. It is made of corrosion resistant .409 stainless steel and should have a lot of life left in it. It is grey in color and has the normal dents and dings typical of a used outdoor wood boiler. It has all the great features of the Heatmaster SS MF-Series(see video below).