Most of our Sterling Heights steam work sits in the southern half of the city, in the 1960s colonials and ranches off Schoenherr Road and Van Dyke Avenue. The larger colonials often have two pipe steam, and the call usually sounds like this: one room is cold, the returns are banging and the gas bill looks wrong.
First thing we do on a two pipe system is a trap survey. We run heat and then check the outlet side of every radiator. A trap that failed open leaves the return pipe right after it hot, because live steam is blowing through. A trap that failed closed leaves the radiator cold, with the steam stopped at the supply valve.
Then we follow the returns back to the boiler. Steam in the returns shoves water around, which is where a lot of the banging comes from. We check the end-of-main traps or vents, the condensate path and the boiler water. If the sight glass shows dirty, bouncing water, the boiler gets skimmed or flushed too.
We mark each trap on a sheet as good, open or closed, and price the bad ones individually. Homes near the Warren border off 13 Mile Road share layouts with their Warren neighbors, so we usually know where the radiators and traps sit before we walk the house. The written estimate comes before any part is changed.