Look, listen, smell and touch - your senses are among the many tools at your disposal that can help you get a better sense of your thermal fluid heater or boiler.
It is unfortunate that heaters and boilers cannot talk. If they could, we might occasionally hear, “Will you please pay attention? I am sick, and something is not right!” Instead, many of us treat the heater like we treat our car and only pay attention to it when it fails. The downtime from a failed heater can quickly turn hard-earned profits into unplanned expenses.
The following 10 tips will help you recognize potential problems and take appropriate actions to avert an unexpected shut down.
Tip 1: Look for Something Different
Trust your eyes. Often, a visual scan of your heater/boiler will help you detect changes to the unit. Look for leaks, which might indicate that internal corrosion and through-wall thinning have occurred. Paint discoloration, another good indicator that is easy to see, can be the result of a hot spot caused by insulation failure.
It also is important to record and plot gauge readings daily. By regularly examining fuel usage, water or thermal fluid usage, and stack temperature readings, you can identify negative trends that might suggest problems with your equipment.
Tip 2: Listen Carefully
correctly just by listening to it. That is because gas and fluid flowing through pipes have distinctly characteristic sounds. Likewise, problems with burners, pumps and some valves (e.g., check valves) can be recognized relatively easily by listening to them and comparing the sounds to those that are considered to be normal. If something sounds bad, then it probably is bad.
Tip 3: Use Your Sense of Smell
Your nose can be another great asset. The smell of gas, a leaking fluid, burnt electrical contacts and even a hot pipe can be great indicators that something is not operating properly. The best opportunity to use your sense of smell is when you first walk into a boiler room. For instance, learn the smell of water treatment chemicals, and use your nose to detect a leak as you walk through the room.
Tip 4: Examine a Sample of the Heater Fluid
Just looking at a sample of water or thermal fluid taken from a heater will provide a good indication of what is happening inside the boiler. A reddish tint, for example, suggests high levels of iron in the water, often the result of internal corrosion. Although particulates present in water may be a result of rust, the same condition in a thermal fluid heater may be an indication of fluid degradation. The fluid in your heater is the blood of your process. If it does not look like it did when you filled the heater, do not ignore the change.
Tip 5: Keep an Eye on the Stack Temperature
The best indicator of heater efficiency is stack temperature. Degradation of heater efficiency often is caused by heater scaling and fouling. In fact, a 1/32" layer of scale can increase fuel costs by several percent. Unfortunately, it is almost impossible to detect scaling or fouling without performing invasive procedures. However, by recording stack temperature on a daily basis and plotting the readings, it is possible to detect changes in efficiency that may be the result of these chronic problems. A simple temperature gauge installed in the stack is the best investment you can make during installation. Contact the heater manufacturer to obtain information regarding normal stack temperatures for a heater setup similar to yours.
Tip 6: Check the Exhaust Color
This practice is hardly ever used because, in many cases, the stack outlet is not located near the boiler room. However, the heater exhaust, especially if it is oil-fired, is a good indication of the combustion efficiency of the heater’s burner. Think about driving behind a car that is experiencing engine problems and smoking profusely. A heater can do the same thing, and it is not a good sign if it is producing smoke of any color. For instance, burners that run too rich will produce brown smoke - usually a good indication of unburned fuel. So, make a point to take a periodic trip to the roof and look at the heater exhaust.
Tip 7: Predict Shutdowns
A heater will occasionally trip offline as the result of low water, low flow or flame failure. Detailed records of these failures should be kept to help predict when a sensing component should be replaced. Extra level, flow and pressure controllers - as well as flame sensor spare parts - stored on the shelf can significantly reduce downtime. When good records are kept and you implement a good preventive maintenance program, component failures such as these can be predicted. With a little preparation, nuisance trips offline can be reduced or averted altogether.
Tip 8: Increase Your Knowledge
Service technicians, water treatment folks and heater and burner company technical support staff are valuable assets - and are only a phone call away. Chances are, these people have heard every possible problem a heater could experience. Read the operations and maintenance manual for the heater and other system components. Listen to your maintenance staff when they tell you something is wrong. Be proactive, and contact the experts about any of the issues mentioned before they grow worse.
Tip 9: Lay Up the Heater Correctly
Much like preparing your lawnmower for storage, there are important actions to be taken to ensure your heater is protected when production has ceased. During idle periods, a heater can experience high corrosion and fouling rates if not properly stored. Be certain your maintenance program includes actions for both short-term and long-term lay up.
Tip 10: Insist on Ownership
All of these tips can be achieved, but only if responsibility for the care of the heater is clearly defined. Responsibility for equipment operation as well as daily and long-term maintenance should be established at the time of installation. Nothing is more frustrating to a plant manager than, during a meeting to discuss a get-well plan for an outage, to hear, “I thought you were taking care of that.” Assign accountability to staff for trending data, contacting vendors, laying up equipment and all the other duties required to keep your equipment in safe and good working order.
The chances of keeping your heater in good health are greatly increased if you learn to recognize the symptoms that precede failure. These 10 tips should help you achieve success and keep your equipment online.
This article originally was published with the title "10 Tips: Keep Your Heater Online " in the September 2009 issue of Process Heating.
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