Radiator air vent opening setting

georgearoush

I am trying to tune the air vent openings on my radiators. I read online that radiators farther from the boiler should have their air vents more open, while those closer to the boiler should be less open.

However, in Dan’s book "We Got Steam Heat", it says that the vent opening should be proportional to the radiator size: the larger the radiator, the more open the air vent should be.

So which approach is correct? I am trying to tune my system, which has radiators on both the first and third floors. Currently, some of the first-floor radiators aren’t heating as effectively as those on the third floor.

This is what I have:

Jamie Hall

Both approaches are correct. Sort of. And neither is. Sort of.

@DanHolohan 's advice is a good place to start. However, he makes the assumption that the mains in the basement are adequately vented — and that is really the place to start.

Then bigger vents on bigger radiators and observe. Now. After observing, you may note that some rooms don't heat up as much, or as fast, as you would like. Others are too warm or too fast. Oddly the place to start playing with vent sizes is on the faster or too warm rooms. Reduce the vent size — but only one size at a time, and try to work with only one or two rooms at a time. It takes a cycle or two for the system to adjust — and you to evaluate the change. Eventually, particularly if there is a room which persistently cold, you can try a bigger vent in that room.

Trial and error.