Cost of an oversized steam boiler

Lurker_2

My steam boiler, while piped well and vented well and so forth, is too large. It's rated for around 280 or so sq feet of steam, which overpowers my 160 sqft of radiators by a good margin (and that's after all of the pickup factor corrections).

Anyway, I haven't yet noticed any fatal flaw from this arrangement -- I put a bunch of lettered Gortons (that is, Cs and Ds) on my radiators and probably more main vents than I need, and the whole system gets the radiators hot in a hurry. In fact, the radiators get hot so fast (they heat across in a few minutes, well before the room starts warming up) that they tend to overshoot the thermostat. Not that I mind, of course -- I set my thermostat to 70 degrees but if I didn't feel so bad about the fuel cost, I'd set it to 73 or something. I like warm.

Anyway, there's no short cycling (it triggers the pressuretrol fairly quickly, but not before heating all of the radiators all the way across), and it seems that my venting is sufficient to vent out the steam as fast as the boiler makes it (at least, no pressure builds up until the radiators are hot), so I'm left to wonder, where is the downside to having the oversized boiler?

-Michael