Originally Posted By: Wolf359
Actually steam is less efficient which is probably why the highest AFUE you'll find is around 82% or so whereas for hot water you'll find that they go to 95% or slightly higher.
Anyway, I have lots of steam boilers and I'd blow those down all the time. The drain valve is pretty low there, normally mine are higher and I have a bucket to catch it all. I normally just blow it down when the boiler is cold, that way you don't end up adding cold water to a hot boiler. Worse would be if you drained out too much water and then added cold water to an empty boiler, I think you'd risk cracking it then. But on yours, the feed button is part of an automatic water feeder so when the low water cut off kicks in, it's supposed to add water to the boiler so in theory you shouldn't run out while draining it. I'd still do it cold though.
You're also missing a tube from the relief valve, in theory if the pressure builds up, it will blow hot water out of that relieve value so you normally want a tube on there that goes to about 6 inches off the ground.
Home Depot also sells new steam vents if the vinegar doesn't clean them out.
Steam is tricky too, you have to make sure that the radiators are pitched right so that the radiator is at an angle so that the water can flow back down the pipe. If it's going the other way, water will pool at one end and when the steam hits it, you'll hear banging. Very common problem.
Interesting point. The lack of low temperatures (you do need to raise steam after all!) creates a situation where you can't condense well, though I'd guess you could modulate. But the biggest benefit of steam that yields net savings it seems, is the minimal thermal mass yet huge efficacy of latent heat games... The issue with a hydronic like mine is that while I'm 95+% efficient, I have to heat gallons upon gallons of water, which also heats the whole system up along the way. Steam systems really use the radiators well as condensers, while the pipes don't have a ton of losses due to fairly poor gas to solid heat transfer rates. So you get more, higher quality heat, closer to where you want it, and don't have as much mass heating up to begin with.
Maybe I'm wrong on some points, but I grew up with steam heat, parents still have it. I'd actually prefer it myself...