Boiler Blog | Nationwide Boiler Inc.

Cleaver-Brooks hosts a number of informative and educational webinars throughout the year.

Be sure to check out the next webinar, scheduled for September 26, 2018 at 2:00pm EST. The material will be focused on educating boiler operators and owners why preventative maintenance is so important. What routine boiler maintenance tasks are required? What is the recommended frequency of each task? All of these questions, and more, will be covered.

Cleaver-Brooks' Warranty & Service Manager John Pemerton will host the webinar - and you won't want to miss it!

Register today!

Routine boiler maintenance is imperative not only for safety, but also to sustain efficiency and reliability of your system. Being proactive rather than reactive is likely to increase the longevity of your boiler as well as help prevent incidents that can result in injuries, damage, or worse. Incorporating routine maintenance into your facilities day-to-day operations will prove its worth with a great deal of short- and long-term benefits.

There are certain maintenance tasks that should be performed daily, and others that should be performed periodically. Below we have provided a list of best practices to follow when putting together your routine boiler maintenance plan.

On a daily basis, you should track and keep a log of the following items:

• Boiler pressure and temperature
• Stack temperature, to determine operational efficiency (a well-tuned boiler should have a stack temperature range of 50 – 100 degrees above the steam or water temperature)
• Gas pressure to the regulator, as well as downstream from it
• Water quality and pH levels, to ensure you are meeting the recommended levels

Blowdown of the boiler (bottom blow) and water column should also be performed on a daily basis. In addition, you should observe boiler and auxiliary equipment daily to ensure proper operation and that there is no damage, leaks, or unusual behavior. 

On a weekly to monthly basis, it’s important to conduct additional visual inspections and observe the operation of certain components for areas that may need to be addressed. This includes:

• Gauge glass
• Fuel supply valves
• Operating and modulating controls, water level controls
• Flame scanner & burner flame pattern
• High- and low-pressure switches, combustion air proving switch
• Indicating lights and alarms

When it comes to the burner, you should inspect the valves, pilot tube, and diffuser thoroughly for any signs of wear that might call for a repair. Also, be sure to observe the entirety of the boiler system for potential hot spots (an indicator of deteriorated refractory) and again, be sure to keep an eye out for any leaks of fuel, water, or flue gas.

Lastly, there are certain items that should be performed on a semi-annual to annual basis. Many of the tasks below can be checked off during the annual inspection, when the boiler is taken offline:

• Open access doors and inspect the fireside of the boiler
• Inspect boiler and tubes for evidence of corrosion; clean tubes and tube sheets thoroughly
• Examine the refractory for large cracks (greater than 1/8”) and patch as necessary
• Conduct safety tests on the gas valves
• Review all electrical connections for tightness, signs of wiring wear
• Check pump alignment on all base-mount pumps

This is also a good time to fully inspect the auxiliaries that provide fuel, air, water, and chemicals to the boiler. In addition, combustion should be reset periodically with the use of a combustion analyzer, for accurate readings of NOx, CO, and O2.

While the guidelines above provide a good baseline of tasks to perform when it comes to routine maintenance, be sure to consider the boiler manufacturer’s recommendations as well.  

When offline, boilers can still be at risk of accumulating corrosion and deterioration that decreases the useful life of a boiler and increases maintenance and repair costs. With proper planning and preparation, a boiler can be taken offline safely with a procedure known as boiler lay up. There are two specific ways to properly shut down your boiler: dry lay up or wet lay up.

Dry lay up is a procedure that involves removing all water and moisture from the boiler. The main advantage of a dry lay up is that you can basically “set it and forget it”. There are no chemical, equipment, or fuel costs. Once completed, the boiler will just need to be checked occasionally to ensure moisture is not getting back into the boiler. A dry lay up is best for extended periods of shutdown. If the system will need to be put back online on short notice or remain in standby, this procedure would not be suitable.

A typical dry lay up procedure involves the following steps:

1.  Perform a lock-out and tag-out and isolate the boiler from the steam system.
2.  Perform column and bottom blowdowns and drain the boiler completely. 
3.  Open the fireside and remove any soot from the tubes. Look for rust or scale on the pressure boundary wall, and further evaluate any   leakage. Inspect refractory and insulation.
4.  Open the waterside and look for signs of gasket leakage and corrosion of the gasket seating surface. Inspect the entire waterside   and evaluate any scale and corrosion.
     - Any scale left on the waterside can trap moisture and oxygen and corrode the boiler further, so remove as much scale as possible.
5.  Dry all surfaces with a fan or electric air heater.
6.  Have a certified boiler inspector perform a thorough examination of all surfaces, internal and external.
7.  Determine if any repairs are required - this may be the ideal time to perform repairs without any incurring downtime, since you are   already preparing for an extended offline period.
8.  Coat the fireside with mineral oil, let it dry and close all openings including the stack. A moisture-absorbing material like silica gel or lime. 

A wet lay up is performed when the boiler is idle in standby; it is still full of water but isolated from the steam system while the burner remains offline. The procedure involves chemically treating the water to protect the metal surfaces of the boiler and is  the ideal lay up method when a boiler might need to be fired on short notice. It does, however, require additional monitoring and treatment costs that aren’t required for a dry lay up.

A typical wet lay up procedure is very similar to a dry lay up, however, the fireside should not be swabbed with mineral oil.

1.  Follow steps 1-7 above.
2.  Fill the boiler with the chemically treated hot water (greater than 180F) to its normal operating level. Allow air to continue to vent until  the boiler is full or until the steam boiler is at its normal operating level and warm.
3. Once complete, boiler water should be circulated periodically to prevent stratification of chemicals. Chemical concentrations should also be monitored routinely.

Before starting a steam boiler in wet lay-up, blow down the boiler to reduce alkalinity, ensure that all tags and locks are removed, and be sure to witness a minimum of three steam cycles before allowing the boiler to run in automatic. This will help ensure proper operation after bringing a system back online from a wet lay up.

If your facility falls under a temporary business closure mandate due to the current state of the COVID-19 pandemic, it is imperative that you follow one of the procedures outlined above to properly shut down your boiler system. View this technical article provided by the National Board for more detailed information on these two types of boiler lay up procedures.

Improper water treatment is the leading cause of tube damage and poor performance in a boiler system. In this month’s edition of Boiler Basics 101, we will discuss the consequences of introducing your boiler to hard water and the importance of utilizing a water softener.

If water is not treated properly before entering the boiler, scale will begin to form due to a chemical imbalance within the tubes. Scale is defined as concentrated minerals being precipitated when the water is evaporating in a boiler. The precipitated minerals consist of a mixture of calcium, magnesium, iron, aluminum, and silica, and are often referred to as “hard minerals”. Scale is detrimental in a boiler system because it acts as an insulator and prevents proper heat transfer. This can lead to decreased boiler efficiency, costly downtime, and even premature boiler failure. Eventually, scale build-up will cause boiler tubes to overheat and rupture.

To help prevent scale and deposit formation, make-up water should be circulated through a water softener before it is fed to the boiler. A water softener is an ion exchanger designed to remove positively charged ions from hard minerals (like magnesium, calcium, and iron) and replace them with negatively charged ions. The resin beads that are inside the resin tank are negatively charged by brine, which contains salt and potassium. As the water goes through the resin tank, the positively charged ions are chemically attracted to the negatively charged resin beads. The hard minerals then stick to the resin as the water runs through the tank, thus turning the water into “soft water”. This process frees the water from these minerals before entering the boiler and decreases the risk of tube scaling and irreversible damage.

Water softening is one of the main ways to increase boiler longevity and maintain boiler performance. Nationwide Boiler’s fleet of mobile boiler rooms, steam plants, and feedwater system trailers include duplex water softening systems to ensure optimum boiler performance. We also have skid-mounted and trailer-enclosed, stand-alone water softeners available for rent or for purchase. It’s important to know that when Nationwide Boiler delivers a rental unit, it is the customer’s responsibility to maintain and supervise the water treatment and chemistry of the water entering their rental boiler.

All boilers are subject to damage if proper water treatment procedures are not followed. This is an important consideration both during operation and when the boiler is idle. To avoid damage and costly repairs, monitor water chemistry routinely and ensure that you are supplying your boiler with soft water at all times.