The call usually sounds like this: the boiler clicks on, runs a few minutes, clicks off, and repeats all evening, yet the far bedrooms never warm up. A lot of White Lake owners assume the thermostat is broken. Sometimes it is, but in a lake house with steam, we suspect the boiler and the venting long before the wall control.
Gary starts by watching a full cycle with a 0 to 3 psi gauge on the boiler. If pressure climbs to the cutout in two or three minutes while the mains are still cold at the far end, air is stuck in the pipes and the boiler has nowhere to send its steam. Then he pulls the pigtail. A plug of black sludge there means the control has been guessing.
Next comes the radiation count. We measure each radiator, add up the EDR, and compare it to the net steam rating on the boiler plate, not the BTU input. In converted cottages the boiler is often far bigger than the radiators need, because the sizing was done by square footage or simply matched the old one. An oversized boiler builds pressure faster than the system can use it.
The fix is usually a cleaned or new pigtail, larger main vents, often Gorton #2s, at the end of each main, and a pressuretrol adjusted so the boiler starts near half a pound and stops below 2 psi. If the boiler is badly oversized, we explain the trade off honestly and note it for whenever replacement comes up. Then we log the settings on a tag.