As we move into fall it is a good time to think about your heating system and required maintenance. Boilers are a big investment that provide an efficient and reliable heating source when properly maintained.
No one intentionally wants to shorten the life of their boiler. However, if proper care and maintenance are neglected your boiler will not run as efficiently, and may result in more costly repairs, or ultimately equipment failure. Below are some standard practice reminders to help avoid any unexpected down time during the fall and winter months.
Poor Water Treatment
Proper feedwater is necessary to prevent scale and buildup. By reducing the levels of dissolved solids and contaminants in the feedwater, you reduce buildup in the boiler. The scale buildup forms an insulating layer that prevents maximum heat transfer and wastes energy. Ultimately, scale buildup that is left unchecked can destroy a boiler. The insulating layer prevents the heat from being transferred to the water, causing the tubes to overheat and eventually fail.
| BOILER SCALE
The chart below outlines the amount of fuel that is lost based on thickness of boiler scale. A boiler will save more in fuel than it could use in water treatment products.
What is the Cost of Running a Boiler with Scale Build Up?
Poor control of water chemistry can lead to pitting and corrosion of the boiler tubes. The use of steam line treatments, oxygen scavengers and other chemical treatments can help maintain proper levels to help avoid pitting and corrosion problems. Water side corrosion can lead to failures in the connections between the tube and tube sheet and sometimes in the tubes themselves. Retubing a boiler isn’t fun for anyone, as it requires the boiler to be put out of service while the work is performed.
Proper feedwater treatment is essential to prolong the life and ensure efficient operation of your boiler equipment. The water side of your boiler should be inspected on a regular basis to make sure your water treatment program is working as expected, and to allow for adjustments.
Improper blowdowns or failure to blow down on a regular schedule can lead to a buildup of solids in the boiler and lower heating efficiency. Adjust surface blowdown to keep boiler water conductivity within acceptable limits. Perform regular bottom blowdowns to prevent buildup, as well as the low-water trips and water column. While the loss of heating efficiency is bad for operating costs, the bigger issue is that the buildup can compromise the level controls and foul the probes that are intended to detect a low water condition.
Low Water Conditions
Low water levels can destroy a boiler. Steel cannot withstand the high temperature of the furnace without the presence of water to absorb the heat. It is important not to attempt to correct a low water condition by introducing water into a hot boiler. The water will promptly flash into steam, increasing in volume by 1600 times, which can result in a boiler explosion. Make sure your boiler has working low-water trip switches installed. Trip switches are installed in legs that have no circulation. They will need to be blown down regularly to avoid having sludge plug the piping and switch. What is the worst that can happen? Below is a photo from a 2007 boiler explosion in Paris, TN.
Operators, when pressed to keep their boilers running, sometimes turn to the practice of installing jumpers across safety interlocks in order to avoid boiler shutdowns. Obviously, these interlocks are intended to maintain the safe operation of the boiler. Defeating their function puts the boiler (as well as the boiler operators) at risk. When a boiler is shutting down due to the action of safety interlocks, the cause should be found and corrected before continuing to run the boiler. If the problem is not corrected, the result could be fatal.
The start-up and shut-down of a system results in more stress on the boiler than continuous operation. A boiler is made up of many different types of materials which operate in different environments. These materials heat up and cool down at different rates. The standard warm up curve for boiler water temperature is 100°F per hour. Gradual warmup will prolong the life of your boiler and reduce the chance of failure.
Safe and reliable operation depends on the skill of the operator. It is important to be proactive and provide regular training and to schedule emergency drills, so operators are equipped to handle any situation. Training is important for all operators, but even more so for newer operators. Do not assume knowledge has been passed down from one operator to the next. A boiler operator who has received training can significantly impact the efficiency and safety of your facility. At Watertech we believe that well-trained employees are happy employees.
Watertech-U, our in-house training facility, offers a variety of free waterside and chemistry training sessions. Our current schedule can be found at: http://www.watertechusa.com/watertech-u
Milwaukee Area Technical College (MATC) offers a Boiler Operator Certificate to prepare operators to safely and efficiently run equipment, and monitor meters, gauges and computerized controls. To learn more about MATC’s Boiler Operator Certificate go to: http://www.matc.edu/tas/certificates/boiler_operator_certificate.cfm
Stay Safe and Stay Warm!
This article outlines a few common problems that can damage or destroy your boiler. By providing proper water treatment and regular maintenance, your boiler should provide safe, efficient and reliable heat for many years. If you have questions about boiler water treatment or operator training, reach out to us at 414.425.3339. Until then, stay safe and stay warm!