Boiler Maintenance: Everything You Need to Know
Understanding Boiler Efficiency
Boilers draw in cool air, heat it up and send it out the stack. Optimal conditions would generate the smallest amount of flue gas (exhaust gas that is expelled) at the lowest possible temperature.
The boiler system takes in cold water, heats it to steam and uses the heat.
While the majority of heat is lost from your boiler in the stack or boiler water, anywhere in the boiler or boiler system that loses heat, steam, condensate or hot water, means we are losing valuable BTU’s.
One of the easiest ways for a business to reduce operating expenses is to use energy efficient equipment. Here are a few quick tips to help make your boiler system more efficient and save money on your monthly bills:
- Install an economizer.
- Install a variable frequency drive.
- Preheat combustion air.
- Return condensate to the boiler.
- Control blowdown rate.
- Survey steam traps.
- Tune your burner regularly for seasonal changes
- Outdoor temperature reset and night set back (hydronic boilers)
Want more information and additional tips? Check out the full list here.
How does boiler feedwater quality affect the operation of my boiler?
Low-quality boiler feedwater contains impurities and gases that can lead to a reduction in efficiency and boiler or system leaks. Pure water is neutral in taste, odor and color. While this is ideal for transporting energy due to its convenient boiling point and steam generation, it is expensive to generate. You are likely to find suspended and dissolved solids as well as dissolved gases in well and municipal water. Feedwater can also contain industrial wastes, sediment and microorganisms.
Poor water treatment can affect your boiler operations in numerous ways:
- Dissolved oxygen can cause oxygen pitting and leaks
- Dissolved CO2 traveling out of the boiler with the steam could make condensate acidic. This acid condensate will corrode away your steam pipe while also adding iron to your boiler water
- Dissolved solids can cause scale to form in feedwater pipes, economizers, and boilers. This scale prevents boiler water from cooling metal heat-absorbing surfaces. As the problem worsens, the boiler can develop tube roll leaks, hot spots and eventually a pressure part failure
- A high concentration of normal boiler impurities, over-treatment with chemicals or an accidental introduction of organic matter (grease or oil) leads to foaming carry-over. This pushes the foam out of the boiler steam outlet and can cause water hammer in a steam line, erosion in steam piping and boiler low water events
Read this article for more information on how feedwater can impact your boiler.
The most effective and lowest cost water treatment program pretreats, deaerates and chemically treats the raw water
- Dissolved gases are primarily removed from feedwater in the deaerator or hot water tank. Careful attention is required to ensure that gases can be safely removed from the boiler water prior to feeding the boiler. Good practice would be to record the feedwater temperature in your boiler logbook during every operator round. Follow with a good chemical treatment program to remove or treat the remaining trace amounts of dissolved gas.
- Dissolved solids, depending on the nature of the impurity, can be removed by a water softener and a Reverse Osmosis (RO) System. Make it a habit to record the makeup water conductivity, feedwater conductivity and boiler water conductivity in your boiler logbook during every operator round.
If carry-over or foaming occurs and boiler water conductivity is within range, call your water treatment company. Tests will determine if the foaming can be addressed with a simple water additive or if the boiler will need to be brought offline and cleaned by a qualified service company to remove contamination.
When should I contact a service company?
- When feedwater temperatures drop below recommended temperatures. (190 F for hot water tanks or 225 F for Deaerators)
- When the feedwater conductivity is above the recommendation of your water treatment company.
- When the boiler water conductivity is above the recommendation of your water treatment company, and blowdown does not get conductivity within range.
- If carry-over is caused ‘mechanically’ or by the way the boiler is being loaded.
Reasons to service your boiler annually
Boiler preventative maintenance will help you steer clear of issues, breakdowns and costly expenses while increasing the longevity of your system and maintaining the safety of your business and employees. Here are some more detailed reasons to keep up with your boiler service schedule:
- Save on Boiler Repairs – Regular boiler maintenance keeps your repair costs down by catching problems early, before they become costly.
- Save Lives – Safety tests performed during regular service appointments can prevent deaths from carbon monoxide poisoning and other dangerous boiler operating scenarios.
- Ensures Insurance Coverage and Staying Under Warranty – Most boiler warranties and insurance policies require annual servicing to ensure coverage.
- Catch Problems Early – Identify any problems and address them before they do any major damage, avoiding expensive repairs and possible replacement of your boiler system.
Routine boiler maintenance
- Check water level gauge glass, record the pressure gauge and temperature gauges
- Check LWCO and ALWCO operation and ensure the burner shuts down
- Blow down the water column and gauge glass
- Turn off burner control switch, observe response to flame failure
- Observe operating control and high limit control
- Perform bottom blowdown to remove sludge and sediment.
- Observer burner refractory cone, looking for broken chunks or hot spots
- Check all linkages on burner controls and on the automatic draft controllers
- Check air damper on burner
- Check valve operation in gas train
- Check pilot and igniter, look at the condition of flame
- Check operation of LWCO – blowdown boiler water level through drain. Watch gauge glass to see burner cut off before losing sight of water
Test your boiler knowledge with this quiz!
The importance of boiler logs
To keep any facility up and running, managers and operators must know the machinery that they are working with. Designing a process that prioritizes transparency reduces boiler accidents and increases the lifetime of your equipment.
Boiler logs tend to land under two categories: daily operational logs and maintenance activity logs. Each boiler in the facility should have a separate log sheet. These should have room for two sets of readings a day at a minimum. Consider 2 sets of readings per shift if running continuously. Also be sure to include weekly and monthly checks and a comments section for notes on irregularities or potential significant events for other operators to act on.
Boiler logs are a standard in maintaining your machinery. Logs should be updated daily with specific, useful information. It is important to be intentional and stick to a schedule because if left unattended, boilers can build dirty firesides or water side scale build-up, which can force emergency shutdowns.
Management should inspect boiler logs and spot check readings to prevent ‘pencil whipping’. If the data in the log is not accurate, it can lead to poor water treatment and maintenance decisions.
Who is responsible for boiler logs?
From the ASME National Board, the breakdown of responsibility for your boiler logs is as follows:
- Operator – Responsible for taking boiler readings, ensuring accuracy and initial analysis.
- Management – Responsible for implementing log program and supervising its continuous completion. Also responsible for ensuring that an analysis program is carried out.
- All Involved Parties – Responsible for retention of logs in accordance with the facility policy. They also must examine logs to determine trends and recommend action in response to these trends.
The cost savings of boiler preventative maintenance
Commercial or industrial boilers are some of the most expensive and valuable assets within a building, and are pertinent to your plant process or producing heat during the cold winter months.
Preventative boiler maintenance will save you money by preventing:
- Fuel Overuse – If your equipment isn’t performing at its best, it will burn more fuel, driving up your bills.
- Minor Problems Becoming Major Problems – Failing to have routine maintenance performed will cost you more in the long run, leading to very expensive repairs or in some cases, a complete replacement.
- Outages – When outages occur due to delayed maintenance, your organization will likely lose revenue.
- Safety Hazards – Routine maintenance can reduce the risk of fire, pressure explosion and carbon monoxide buildup by ensuring devices are clean, functional and properly ventilated.
Contingency planning will save you from drowning in repair costs or hemorrhaging revenue due to a facility shutdown. A contingency plan should follow these basic steps:
- Review Your Insurance Policy – Make sure you’re fully covered and your system is good to go in case of emergencies. If you aren’t sure, check with your insurance agent and your mechanical service provider.
- Get Familiar with Your Machinery – Keep up with your boiler logs and conduct preliminary tests to check your boiler system is switched on and functioning before you need it.
- Have a Backup Handy – Nobody expects the worst to happen, but when it does and your business is in need of a boiler, you want to make sure you’re covered. At Rasmussen Mechanical Services, we offer rental boilers along with a team of experts and 24-hour emergency service so that you never have to wait for a solution.
Rasmussen Mechanical Services’ Boiler Repair and Code Services Division focuses on delivering swift, quality services and repairs for our customers. We hold R, S, H, U, and PP stamps and our extensively trained crew of certified welders is equipped to perform a full array of ASME Code Services and NBIC repairs.