How does a vaporstat save you $$?

Jason_44

The boiler is definitely oversized (500 sq ft of steam for only 350 sq ft of radiation). I don't have money to replace it right now. The burner has been downfired with the smallest-allowed oil nozzle (I think the tech told me 1gpm).

I took your advice and put two Gorton #2's on the main. It's helped a lot, but there's still a bit of hissing in a couple of the larger radiators. Perhaps I need bigger vents on those radiators? It's just that the two biggest radiators are in the room with the wall thermostat. Does that matter? I'm worried that if those two big radiators vent too fast the thermostat will get satisfied too quickly and shut off the burner before all the other radiators are hot.

Jason

Jason_44

Provided a steam boiler is properly piped (i.e. dry steam) and the mains are adequately vented, what's the main advantage of a vaporstat over a pressuretrol?

My pressuretrol cycles the burner on and off occasionally until the air is out of everything (mains and rads), as long as the wall thermostat is calling for heat.

If a vaporstat is "more sensitive," wouldn't that just cause the burner to cycle on and off more? And if that happens, aren't you just wasting fuel due to short-cycling?

Jason

Steamhead (in transit)

Since steam can be compressed

the higher the pressure, the more the steam is compressed. The boiler has to run longer and generate more steam to do this. So the lower the pressure, the less the boiler runs.

Your situation sounds like the boiler may be slightly oversized, or the air isn't venting quickly enough, or both. The system should be completely full of steam before the pressure starts to build.

Once everything is dialed in, a Vaporstat will not cause short-cycling.

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