I just had my boiler for my single pipe residential steam heat system changed. My old boiler was a 45 year old PENCO that finally developed a leak in the casting and the new replacement boiler is a Burnham. I am now getting surging, bubbling and tons and tons of rust and sludge into the boiler. Why is this happening and how do I fix it? I have had people tell me to use a commercial chemical flush and other people say don't ever do this. I've also been told just to keep on boiling the water and flushing the system and it will eventually come clean. It seems like it will take forver.