Steam Boiler Preventative Maintenance Musts
Industrial steam boilers are found in essential systems in almost every industry, from hospitals to food processing. Boilers provide heat, hot water or both, and they must do so reliably to keep processes running smoothly. Due to their importance, preventative maintenance (PM) is necessary for all industrial steam boilers if managers want to maximize uptime and minimize repair costs. In this guide, we’ll discuss how to have an effective PM program.
Why Maintenance Is Important for Your Facility
A PM program will cost your business money, so it’s important to understand how the benefits of maintenance stack up to the associated costs. The most obvious advantage of maintenance is preventing boiler failure, which can lead to hours or even days of expensive downtime in some cases. However, you should also consider:
- Increased safety and reliability
- Reduced replacement costs
- Better inventory management
- Predictable downtime for maintenance
- Reduced downtime during steam boiler annual inspection
- Increased energy efficiency
- Water savings
These advantages are significant, but many managers still wonder when the right time is to start a preventative maintenance schedule. PM programs are the most beneficial when system components develop higher failure rates, and when repairs start costing more than implementing the program. It’s also important to take into account the less obvious costs associated with component or system failure, like potential lawsuits and general loss of goodwill.
Here are three crucial reasons to implement a PM program:
1. Maintain Water Quality
The efficiency of your industrial steam boiler is directly connected to water quality. As the boiler converts water into steam, any impurities or oil present in the water will reduce the quality of the steam. Dirty water can also cause short cycling and wet steam. Both of these issues result in wasted energy and higher operating costs. Your daily steam boiler maintenance checklist should include checking all relevant gauges to identify if the boiler is dirty.
If water is moving around quickly and bouncing behind the glass, there is oil in the water. If water is dripping from the top of the gauge, the boiler is churning out wet steam. Wet steam doesn’t heat as quickly or efficiently, forcing the burner to run longer.
Boiler maintenance includes having water chemically tested by professionals. The results of these tests will indicate if the water quality is good enough to stop premature corrosion, the buildup of scale and other problems that will shorten the lifespan of the boiler or hamper its efficiency.
2. Ensure Proper Boiler Blow Down
Blow down is the process of draining water from the boiler periodically. This is essential because solids dissolve in the make-up water as the boiler removes pure water in the form of steam. Solids buildup contributes to poor water quality, increasing corrosion and scale.
The bottom of the boiler contains the greatest amount of sludge. The skimmer drain valve enters the boiler slightly below water level, where the concentration of dissolved solids is highest. Skimmer blow down is highly efficient and essential in controlling concentration cycles, while bottom blow down is necessary to prevent dangerous sludge buildup. Proper blow down is a central element of boiler maintenance, and you should consult an expert on how often to perform this maintenance task, according to your particular system and application.
3. Facilitate Appropriate Insulation
Insulation is central to the safe and efficient operation of an industrial steam boiler. There is a huge variance in the amount of insulation required, as well as the material the insulation is made from. Depending on the size of the pipe and its temperature in operation, insulation could range from just an inch to several inches. Steam boilers commonly use these insulation materials:
- Mineral fiber
- Calcium silicate
- Cellular glass
Insulation maintenance includes inspecting the piping, boiler surfaces and fittings. Inspection should look for wet or deteriorated insulation.
How to Manage System Diagnostics
Diagnostics are highly valuable as part of a preventative maintenance program. They can increase the boiler’s lifespan and its operating efficiency. Some of the diagnostics to incorporate include:
- Using meters on make-up water lines and monitoring the flow. In closed-loop systems, this helps identify leaks in the boiler.
- Blowing down on a regular schedule but not repeating it too often. Blowing down too often is a waste of water, chemicals and labor.
- Inspecting the chemical make-up of the water regularly.
- Checking steam traps and steam lines for leakage.
- Tuning boilers to optimize their performance and reduce premature wear and tear.
- Ensuring the efficient operation of condensate pumps.
- Inspecting safeties, gauge glass, scanners, pressure switches and pressure controls.
A diagnostics system allows managers to keep an eye on critical data that can indicate when a problem is on the horizon. This preventative approach keeps unexpected downtime to a minimum and provides a clearer picture of the boiler system’s overall health.
How to Manage Steam Boiler Components
Every component in an industrial steam boiler has its own vulnerabilities and needs when it comes to maintenance. The following are the most important components to cover during routine maintenance:
The drum is the most expensive part of a boiler, and corrosion is the issue managers and technicians have to worry about most frequently. One form of preventative maintenance for the drum is wet fluorescent magnetic particle testing (WFMT). This method of inspection indicates the condition of welds and some ligaments. Should a WFMT reveal corrosion in the drum, an ultrasonic thickness test (UTT) can reveal the current thickness of the metal.
A boiler’s firebox can rapidly accumulate soot, resulting in reduced heat transfer that drives down the system’s efficiency. Fireboxes need to be cleaned regularly to ensure the heat transfer surfaces remain clear.
Headers tend to suffer from corrosion or erosion as well as weakened metal. Maintenance for these components includes WFMT, a dry-powder magnetic particle test or both. A visual probe can help with evaluating cleanliness and finding blockages that obstruct the flow. Superheater headers and water-circuit headers should receive a visual inspection, as well.
Main Steam Piping
Main pipes face the same dangers as headers. The main method of maintenance for these components is to check horizontal and non-draining runs with a probe or ultrasonic thickness test to identify any pitting or corrosion taking place inside the pipes.
Failing tubes are a common cause of unexpected boiler downtime. Deposits can accrue steam-side or water-side, which inhibits heat transfer. Tubing can also suffer from blockage, fatigue and corrosion. A maintenance inspection should look for any damage to tubing surfaces, swellings, distortions or discoloration. Tubing is another area where UTT can provide valuable information.
Most de-aerators are split into two parts. The first section separates out dissolved gas from the water. The other section acts as storage for the de-aerated water, and technicians may add chemicals before the water moves to the boiler’s higher-pressure system. De-aerators should undergo WFMT regularly.
Air openings are part of the combustion process. Maintenance for these openings consists of simple visual inspection and removal of any debris or blockages.
Most facilities don’t have the luxury of using completely clean feedwater, and rely on municipal water supplies. In these supplies, there are typically solids that may be suspended or dissolved. Dissolved gasses, sediment and microorganisms are other issues to consider. Here are some of the issues that can occur with badly treated water:
- Leaking and pitting caused by dissolved oxygen.
- Condensate coming out as acidic due to CO2 mixing with the steam exiting the boiler.
- Scale in feedwater pipes, caused by dissolved solids.
For this area of piping, corrosion and scale are the issues to worry about. Corrosion is especially likely over time, as the pressure of the flow through these pipes is high. To avoid piping failure in this component, the maintenance technician should use a video probe wherever possible to conduct a visual inspection of the pipe interiors. If there is a reason to suspect corrosion, a UTT can confirm the amount of damage done.
Corrosion can severely affect return lines as rust forms and follows water flow down the return. This leads to clogging that causes condensate to rise upward into the system’s mains. Flushing return lines regularly and monitoring for corrosion with periodic UTTs is important for maintenance. To keep corrosion to a minimum, the maintenance program should take advantage of chemical treatments specific to return lines.
A malfunctioning circulator pump inhibits the efficiency of water circulation or stops circulation altogether. Circulator pump maintenance involves listening for unusual noises that may indicate failing components, like bearings or valves. Technicians should also thoroughly check for leaks, which are frequently the result of corrosion in mounting bolts, valves and seals.
Flue-Gas Vent System
This set of components vents gas to the outside, making it a critical part of the boiler’s safety system. The main objective with maintenance in this area is preventing any leaks, obstructions or excess pressure on the boiler. During maintenance, the technician will look for and remove blockages, fix leaks and clean the system. If your boiler’s stack is long, consider making the run shorter or setting up fans to facilitate better flue gas movement.
Pilot and Main Burners
The pilot and burners frequently suffer from intermittent or otherwise improper flames and discoloration from dust buildup. When a maintenance technician is addressing these components, they will give the burners a visual inspection. They will also remove the burners, brush them, vacuum them and adjust the fire rate. The thermocouple should glow red and remain immersed in the cone.
The main things to look for on the safeties are scale, plus general wear and tear. You can confirm safeties are working by performing a bottom blow down. The blow down will test the low-water cutoffs. The frequency of blow downs varies based on how much condensate comes back to the boiler and the quality of your water.
Bottom blow downs should begin with both valves totally shut. First, open the knife valve. Then, open and close the gate valve. For boilers with both a front and back drain valve, make sure to do this on both sides. Then, perform the procedure three times in succession. This moves the water around in the boiler and encourages sludge to move toward the drain.
In addition to regular blow down testing, technicians can perform preventative maintenance by cleaning the site glass and testing scanners by removing the flame and observing whether the boiler ignites.
A boiler’s heat exchanger is highly susceptible to buildup of mineral deposits, as cold and hot water constantly flow over metal plates. This results in scale that reduces space for water flow, increasing the pressure drop across the exchanger and forcing the pump to work harder to achieve the required flow. Maintenance for heat exchangers consists of ensuring the best water quality to reduce the rate of buildup and descaling the plates frequently.
Industrial Boiler Maintenance Checklists
Since boiler systems are so complex, it’s crucial to monitor them continuously. A PM program will enable managers and technicians to identify when the system is unsafe or operating inefficiently. Some aspects of maintenance should be conducted daily or almost daily. Others should be done once a week or once a month, in addition to steam boiler annual maintenance.
Below are the industrial steam boiler maintenance checklists to go through each day, each week and each month.
Daily Maintenance Checklist
A technician should be on site every day to do the following:
- Perform a bottom blow down.
- Perform a water column blow down, opening the drain to stop float damage from occurring.
- Log pressure and temperature of the boiler to ensure it is capable of handling the load.
- Log the stack temperature to determine efficiency.
- Check pressure level where gas flows into the pressure regular, as well as downstream pressure.
- If the boiler is hydronic, check the supply and return temperatures.
- Look through the sight port for a visual inspection of sooting or impingement in the flame.
- Check for the proper function of other systems and equipment connected to the boiler, such as the water softener and chemical feed system.
Although you may not need to take water samples every single day, the more information you have about your water quality, the better.
Weekly Maintenance Checklist
Weekly boiler maintenance involves choosing a day each week to do the following:
- Perform an evaporation test to ensure the low water level control is working properly and the burner shuts off when water reaches the low point.
- Look for etching or other wear on the low water cutoff gauge.
- Test operation in the fuel supply valves.
- Ensure the burner’s single point positioning system is in good shape, checking for wear, as well as hysteresis or slip where applicable.
- Ensure the burner shuts off at the right time when pulling out the flame scanner.
- Test indicator or running lights.
- Ensure alarms are functioning properly.
- Listen to the boiler’s motors to ensure they are running smoothly without excess noise or vibration.
- Perform a visual inspection looking for leaks of flue gas, water or fuel.
- Test switches, including the high-pressure, low-pressure and combustion air switch.
These weekly tests are often the most time-consuming, yet the most important to safety and function.
Monthly Maintenance Checklist
There are a few things to check off the maintenance list once each month. The technician should check:
- The burner diffuser, to identify cracking, burning or other types of deformation.
- The burner pilot tube, to ensure the electrode is functioning and properly sparking pilot light ignition.
- Air damper devices, which should all have freedom of movement.
- The boiler exterior, which can show signs of dangerous hot spots.
Contact Chardon Laboratories for Industrial Boiler Water Treatment
Maintaining industrial boilers doesn’t have to be a fully in-house job. Chardon Labs can provide a comprehensive boiler water treatment system to keep your boilers from becoming corroded, pitted or otherwise damaged due to poor water quality. Our technicians are ISO-certified and equipped to handle a variety of water treatment services from the free survey evaluating your current system needs to the regularly scheduled testing and treatment your system needs to stay healthy and efficient.
Our cutting-edge electronic service reporting system tracks everything we do from the moment our technician arrives at your facility. Your eReport is available the same day we perform services and indicates exactly what the technician did and when they did it. Chardon Labs doesn’t just sell chemicals — we offer clean systems to keep your costs low and your boilers operating with minimal waste. To learn more about setting up the right water treatment schedule, contact us at 1-800-848-9526 or get in touch online.