So what is it, a furnace (hot air) or a boiler (hot water or steam)? If it is a boiler does it supply hot water or steam? Do you have cast iron radiators in your house or baseboard heaters? What is the name/manufacturer of the equipment and what is the model number?
But most of all, can you post some pictures of the equipment?
To post pictures you need to first upload the pictures to a photo hosting site such as photobucket.com or villagephotos.com. and then post the public URLs for the pictures (or album) here. More pictures are always better than fewer. Please have CLEAR pictures and have both close up pictures and ones from a far enough distance that we can see how the various parts are interconnected.