Low pressure Steam Boilers
In the State of Michigan a low pressure steam boiler is a boiler that operates at less than 15 PSI of pressure. Low pressure steam boilers utilize the latent heat of vaporization to transfer heat efficiently. For a detailed explanation of the latent heat of vaporization CLICK HERE. For the purposes of staying on point, we'll just say that it takes about twelve times the energy (heat) to change the state of water from a vapor to a liquid than it does to change the same mass of water by one degree F. Basically, steam has to lose a lot of heat to change to a liquid.
A steam boiler system that utilizes the same water over and over again without adding water to the system can be described as closed-loop system. A steam boiler system that adds water because steam or liquid water is expelled from the system can be described as a open-loop system. Nearly every low pressure steam heating boiler system is a closed-loop system. A low pressure steam heating boiler that was designed to be a closed loop system but that loses much of it's water is described as a loose system. Likewise, a low pressure steam heating boiler system that was designed to be a closed loop system that loses none or very little of it's water is described as a tight system.
Loose or open loop low pressure steam heating boiler systems often have serious issues with mineral deposits or scaling. Because scale is an insulator, it is prudent to address scaling on all boiler systems. Johnson Heating and Cooling, LLC provides the best chemical treatment programs in the industry. Because mineral deposits have such a drastic impact on efficiency, open-loop low pressure steam heating boilers are almost never used in Michigan. A very thin layer of scale on a heat exchanger is a good sign on some low pressure steam boilers, but it is important to emphasize "very thin". Boiler makers refer to a very thin layer of scale as being "egg shell". The reason why a very thin layer is a good sign on some boilers is because it is not a thick layer, but also because it shows that the heat exchanger is not being corroded by acidic water.
The picture, on the left, below shows the inside of a low pressure steam process boiler that has a little bit too much scale on it's fire tubes. Notice that the tube right-of-center has been replaced recently. The center picture shows the sludge that can form in a loose system over the coarse of just one heating season. The right picture shows how the sludge can become lodged in the low water cut-off mechanism, creating a dangerous situation in which a boiler may explode like a giant hand grenade.
Steam boilers that utilize the old fashioned cast iron radiators function by directing steam into the top of the radiator. As the steam travels downward towards the bottom of the radiator, it gives off heat and changes it's state to a liquid. The liquid water travels through the return lines to a device called a steam trap. Steam traps function very much like a toilet bowl float mechanism in that a float controls a valve which only allows liquid water to return to the boiler or it's water supply tank. If the steam trap is full of vapor and has no water in it, it's valve will be closed. Once the water level in the steam trap lifts the float, the valve opens and allows the liquid water to return to the holding tank which pumps water into the boiler. There are many different variations in the design of steam heating systems, and the functionality of the system described is specific to systems with the same design as the one described, however the system described is very common in the Detroit metropolitan area. Some steam heating systems do not utilize a holding tank, for example, but many do.
Installing steam heating systems and steam heating boilers is as much of an art as it is a science. Many authors refer to previous generations of steam heating boiler makers as "the dead men" because steam heating is a bit of a lost art in America. David Johnson Jr., the owner of Johnson Heating and Cooling, LLC has had the privilege of being trained by the best boiler makers in the State of Michigan from a very young age. Many boiler makers have family members in the industry, and David is no exception. With about two dozen family members in the industry, David has had the great opportunity to work with, and be trained by, some of the most skilled and talented boiler makers in the State of Michigan. When experience, knowledge, skill, and hard work are needed, Johnson Heating and Cooling is an excellent choice for providing your boiler needs.
If you live in the State of Michigan and need boiler repair, boiler installation, boiler service, or just a good boiler repair company, give us a call. We have two decades of experience working on boilers and hydronic heating systems, our rates are competitive, and we always treat our customers the way that we would like our families to be treated if they were in your shoes. If you would like to learn more about some of the work that we have done, and look into some of our references that are local to you, just navigate to our contact page and click on the link to your township or city. We have listed a few references from several areas in Macomb and Oakland Counties that are organized under their respective township/city and area codes.
Boiler Service and Maintenance
- CSD-1 Reports