A typical 48093 call: an early 1960s two-story near the GM Technical Center on Mound Road, two pipe steam, and a gas bill that jumped this winter. The house heats, but unevenly. Quick observation first. The gauge reads close to 5 psi and the pressuretrol is set well above where a house needs it. Somebody turned it up years ago to chase a cold room.
Then we put a hand near the dry return lines. They should be warm, not hot. Hot returns mean steam is getting past traps that failed open, and the boiler is heating the basement ceiling instead of the bedrooms. We go radiator by radiator with a thermometer on each trap outlet and mark the ones passing live steam.
The fix is usually two parts. Replace the failed traps, then bring the pressure down where it belongs, cutting in around half a pound and out under 2 psi. A house this size heats on ounces of pressure, not pounds. With tight traps and low pressure, the system heats evenly and the burner runs less.
We also blow out the pigtail, because a clogged one lets the pressuretrol miss real pressure. Then we test the low water cutoff and leave a written note on the boiler with the settings we left. Being based on Farnum Ave, we are close enough to come back and check it on the first real cold snap.