A homeowner off Main Street calls because the boiler keeps adding water and the feeder clicks on almost every day. That is our clue something is leaking. First we read the feeder's water meter when it has one, and we ask when the problem started. A slow leak over months points one way. A sudden change after a hard freeze points another.
We start at the boiler and work outward. We check the sections for rust streaks or white mineral trails, then look at every fitting in the near-boiler piping. Next we follow the wet return along the basement floor. In homes this age, the return may run under a concrete patch or behind a wall someone added later, so we look for damp spots, rust stains and soft floor.
The steamfitters who piped these village houses knew their business, and their layout is usually sound. Trouble tends to come from later changes. We have found Hartford Loops set at the wrong height after a boiler swap, and returns patched with mismatched pipe. When the leak is in the return, we replace that run. When the leak is in the boiler itself, we show the owner exactly where.
Once the leak is fixed, we refill, skim the water and run the boiler with the feeder valve closed so we can watch the sight glass hold steady. We note the water line, the pressure setting and the date on a tag near the boiler. Then we show the owner how to read the glass each week in season, so they spot a drop early next time.