Steam Systems

Steam systems are either 1-pipe or 2-pipe; the most common is 1-pipe. The reason is cost of installation. The principals of steam heat remain the same for both systems, it's the distribution system that differs. You can tell which system you have by looking at one of your radiators. In a 1-pipe system a pipe will come up from the floor and have a shut off valve on top of it. It will connect to the bottom of one side of the radiator and on the other side of the radiator there will be an air vent valve. The steam comes up from this pipe into the radiator and gives off heat. The steam then condenses into water and drips back down the same pipe. Hence the term 1-pipe. In a 2-pipe system a pipe will come up from the floor and go to the top of one side of the radiator. There will be a shut off valve at the top of this pipe. On the other side of the radiator at the bottom there will be another pipe with no shut off valve, that goes into the floor. The steam comes up from the boiler through the pipe with the shut off valve. The steam enters the radiator on the topside of it and gives off heat. It then condenses into water and drips back to the boiler through a pipe located at the bottom side of the radiator. Hence the term 2-pipe.

One of the most common problems with radiators is the improper tilt of the radiator. There are two telltale signs that determine this. Only half the radiator gets hot and knocking occurs when the steam comes up. What causes this is water being trapped in the radiator. In a 1-pipe system the side of the radiator that does not have the pipe connected to it should be shimmed with a thin piece of wood. This side must be higher than the other side so the water can drip back to the boiler. In a 2-pipe system the side that should be shimmed is the side with the pipe that goes to the top of the radiator and has a shut off valve on top of it. This side should be higher so the water can drip back to the boiler through the pipe located on the other side of the radiator.

Both systems boil water to create steam. If you look at the boiler along with the piping system and radiators, it would resemble a giant still. When you distill water, you purify it. You physically separate the impurities in water, such as chlorine, salt and minerals from the hydrogen and oxygen in water. This is the residue that is left in the boiler after creating steam in it. This residue is usually a reddish brown color, it is not rust. The colder it is outside during the winter, the more steam your system will create to heat your home, the more residue you will have in the boiler. As this residue builds up inside the boiler, the thicker the water will get. The thicker the water gets, the more it cost you to boil the water. Just like it takes longer to boil soup than it does water and it cost less to boil water. By draining the boiler weekly during the winter will actually lower your fuel bills.

The recommended water level in both systems is 1/2 to 3/4th full. The reason for this is known as a steam dome. This is the area from the top of the water to the top of the boiler. The purpose of the steam dome is to allow for the expansion of the steam inside the boiler. If you violate the steam dome by having too much water in the boiler, it will make it more difficult for the steam to leave the boiler. This will increase your fuel bills.

Steam pipes that are not insulated can literally double your fuel bills. They will act as a radiator, give off heat and cause the steam to condense and drip back to the boiler before ever reaching the radiators. The real problem here is the masonry in the basement is a heat sink. What the term implies is something that drains heat out of the home. One characteristic of heat is that it rises, another is that it tries to equalize with its surroundings. In other words, if the ceiling of the basement is 70 degrees F. and the basement walls and floor is 55 degrees F. The heat from the steam pipes are attracted more to the walls and floor of the basement than it is to the ceiling. You are more or less heating the great outdoors.

With steam 1-pipe systems you will find air vent valves on every radiator and on the steam pipes in the basement. What these valves do is allow the air in the pipes and radiators to leave them so the steam can enter. In other words steam cannot occupy a space that is already occupied with air. The faster the air leaves the faster you get heat and the less it cost you to heat your home. If you were to cut open one of these valves, you would see a small copper ball or tube. Once the steam fills the radiator, this copper ball or tube closes the valve to trap in the steam. If you ever saw a copper penny in water, after awhile the penny changes this greenish color. This is known a copper oxide. The same thing occurs inside your vent valves. After a period of time this corrosion will build up on the inside of the valve and it will prohibit the valve from either opening or closing. The result will be higher fuel bills. The way to correct this is to clean the valve. The only time you actually have to replace a valve is when you inadvertently painted it or the corrosion is so severe, it cannot be cleaned. To clean the valve you have to turn off the radiator or heating system and let it cool. Unscrew the valve and place it in a pot with a solution of 50% water and 50% vinegar. Boil the valve for 30 minutes, let cool and then screw it back on the radiator. Turn on the radiator or heating system.

The following link provides you with answers to a lot of the problems with steam systems and solutions. HeatingHelp.com

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