Steam boilers are the workhorse of most modern commercial laundry facilities, providing enormous quantities of steam that can be used to quickly and thoroughly sterilize clothing, fabrics and furniture. However, while commercial steam boilers are generally very robust and reliable, they are still vulnerable to a serious problem that can affect any kind of boiler, large or small — kettling.
What Is Kettling?
One of the most important parts of any steam boiler is the heat exchanger, which transfers heat from the boiler's combustion chamber to its water reservoir, producing steam. While your laundry's steam boiler is functioning, water is constantly boiling and evaporating around the heat exchanger. However, the water used in many commercial laundry boilers is far from pure.
Municipal water supplies generally contain trace minerals and other solid contaminants, such as calcium and magnesium salts. Water that contains large concentrations of mineral solids is known as 'hard' water. When hard water evaporates around a steam boiler's heat exchanger, these minerals are left behind, causing a solid crust of limescale and other mineral deposits to form on the exchanger.
As more hard water evaporates around the boiler, this mineral crust will get thicker, reducing the boiler's water capacity and seriously restricting water flow in and around the heat exchanger. Eventually, this can cause the boiler to make loud whistling and thumping noises, similar to those made by a boiling tea kettle. This is the phenomenon known as kettling.
Is Kettling Dangerous?
Kettling may have a quaint name, but any commercial laundry with a kettling boiler should take the problem very seriously. For starters, the solid barrier that has formed around the exchanger prevents it from efficiently transmitting heat into the boiler's water supply, forcing your boiler to use more fuel and/or energy to maintain adequate temperatures.
Using more fuel and energy to achieve the same results can make your boiler significantly more expensive to run, and the constant overwork can significantly shorten your boiler's working lifespan. However, kettling can be a warning sign for an even more serious problem.
If mineral deposits inside the heat exchanger become too thick, they can prevent water flowing through it at a constant rate, causing pockets of isolated, superheated water and steam to form. This can cause the heat exchanger to suddenly and violently rupture, a catastrophic failure that can render the entire boiler unusable and may pose a serious danger to nearby personnel.
What Should You Do If Your Laundry Steam Boiler Is Kettling?
If one or more of your commercial laundry's steam boilers are showing signs of kettling, you must deactivate them as quickly as possible, regardless of the circumstances. Heat exchanger ruptures are both highly dangerous and completely unpredictable, and running a kettling boiler is never worth the risk.
Once the boiler(s) have been deactivated, the boiler must be flushed and the mineral deposits within removed. This isn't exactly a DIY job, so you should always call in a reputable boiler repair service to have the boiler professionally flushed and cleaned.
Professional boiler technicians will also inspect the steam boiler for signs of damage that may have been caused while the boiler was kettling. Heat exchangers are particularly vulnerable, but the overheating that causes kettling can also damage the combustion chamber, thermostats, and other vital components.
For more information, contact a boiler repair service.
