Home Heating System – Steam Radiators
For those of us in older homes, primarily pre-1940’s vintage, we have had to deal with various remodeling projects involving replacing/renovating windows, replacing roofs, adding wall/ceiling/roof insulation and upgrading plumbing, etc. This current snow storm with high winds, followed by the forecasted air temperatures dropping to around 0 deg. F. at the end of this week, is really exposing many weak links, flaws and other issues involved in keeping our homes comfortably warm.
For our circa-1930 Tudor-style home we have done most of these projects over the years For our heating system, I have serviced annually the fuel oil burning Weil-McLain boiler that provides steam heat via a one-pipe system, that uses black iron pipes with compression fittings connecting to iron radiators throughout the house. One important aspect to ensure that this type of heating system works as designed is to check each of the steam air valves/vents on every radiator to ensure they are working properly.
Due to this current and forecasted severe cold weather period, this past week I decided to check all of the steam air valve/vents on our radiators, which are Maid-O-Mist Jacobus Steam Vents. Sure enough, many of them were clogged. These often-ignored devices are an important aspect of ensuring that the heating system is working properly and efficiently. After about 4-5 winter heating seasons, some of these air vents become clogged and corroded with dirty/rusty sediment and no longer work as intended, causing the radiator to not heat effectively or spew steam constantly, reducing the system’s efficiency. Some of our vents were even much older than that…
These air vents are supposed to hiss initially when the steam enters the pipes and radiators, pushing out the cooler ambient air. Once the steam has replaced the cooler air inside the radiator, an internal float in the vent will close trapping the steam inside. As the steam transfers its heat to the cast iron to “radiate” into the room, it cools and transforms back into water and the condensation flows back out the same pipe to the returns leading back to the boiler in a closed loop.
For those of you who may have this type of heating system in your home, you should check to make sure they are working properly. A correctly sized and installed steam system will have radiators with vents of differing sizes so that the steam distribution is balanced throughout the system. Generally, you want larger vents (faster venting) on the distant radiators, as well as larger vents on the very large radiators (regardless of location). You want the all radiators to heat up at the same time, except you want the radiator in the room with the thermostat for the furnace to have a smaller vent opening so it will be a little bit slower so you don't satisfy the set temperature on that thermostat before the other rooms throughout the house are warm. An important lesson here is that the longer it takes the air to leave the radiator, the longer it takes for steam to fill it and the longer you burner will use fuel. There is a limit to how fast you can vent, especially on the larger radiators. Beyond a certain rate, too much steam will condense at a rate faster than can drain out of the radiator and it'll spit out the valve.
Also, when we renovated our bathrooms, I replaced the iron radiators with a slimmer, more contemporary style of welded steel radiator that is manufactured by STEAMRADIATORS in Ward Hill, MA. (FYI, they are at www.steamradiators.com) They are a subsidiary of RUNTAL, which is a big European low-profile hot water radiator manufacturer. Those of you who have traveled in Europe have probably seen their radiators. They work fine and look really good, taking up much less space and are wall-mounted, as opposed to being floor-mounted.
Good luck to everyone on dealing with this nasty cold spell…..
AVB-AMG