So you’ve received a claim for a boiler that is leaking water, what next? This is likely occurring during cold weather and the insured needs to get the heat back on to the building. Can the boiler be replaced immediately? Is there coverage for this loss? What questions do you need to ask? Once you know some of the basics of boiler claims, it is generally a straightforward analysis.
How do boilers generally fail?
Boilers are robust pieces of equipment that, when well maintained, can last for many years of trouble free operation. When not maintained properly, they can fail unexpectedly and often at inconvenient times.
This occurs when a boiler is allowed to run low on water and the metal structure of the boiler overheats. Boilers are heated by a flame that is in direct contact with cast iron or steel boiler components. Under normal conditions, the heat from the flame is conducted through the metal and to the water, thus heating the water. If the boiler is low on water, not as much heat can be transferred to the remaining water and the metal will overheat. In severe cases, the overheated metal will warp or crack, causing the boiler to leak.
(Fig. 1: Boiler section cracked due to dry-firing)
Steam boilers are normally installed with multiple safety devices that are intended to protect against such an occurrence. The safety devices utilize mechanical float switches, electronic probes, or a combination of both to protect the boiler from overheating. In order to function properly, these devices require routine maintenance.
Float type low water cutoff switches must be “blown down” on a regular basis (generally weekly) to flush contaminants from the float chamber and ensure that the switch is operating properly. Many maintenance technicians know that this must be done, but don’t verify that the boiler shuts down during blowdown and are not verifying the proper operation of the switch. In the case of either a float or electronic probe type switch, the device must be opened and cleaned on an annual basis to remove sludge and mineral buildup.
Float type switches generally fail due to a buildup of sludge in the float chamber, which causes the float to freeze in place, thus rendering it ineffective. The piping that connects the float chamber to the boiler can also become plugged with sludge and cause the switch to fail.
(Fig. 2 Heavy sludge buildup in a float chamber)
Probe type switches can fail when sludge or mineral deposits form a bridge between the probe and the shell. This can trick the switch into thinking that the water level is appropriate when it is actually low.
Dry-firing is a common cause of damage to a boiler, but is not the only possible cause of a premature boiler failure. Since dry-firing is covered under many boiler and machinery insurance policies, it is often claimed as the cause of loss, even when it is not the true cause.
Since boilers are typically constructed of steel or cast iron and filled with water, they would be expected to rust out over time, right? Rust on a piece of metal is actually a protective coating that keeps the underlying metal from continued corrosion. If the PH of the water is neutral and nothing impacts the surface, the metal can last indefinitely in this condition and the iron oxide (rust) layer continues to protect the rest of the metal structure.
If excessive levels of oxygen are introduced into the system, either from air trapped in the system or excessive makeup water (think steam or condensate leaks), the water can turn acidic. This acidic water attacks and removes the protective layer of rust on the metal components and causes the metal underneath to rust. After this cycle repeats over an extended period of time, the continued etching and rusting of the metal can cause a hole to corrode right through the side of the boiler section. A similar situation can occur from improper water treatment programs.
(Fig. 3: Hole corroded through upper left corner of boiler section)
Wear and Tear
As with any mechanical equipment, individual parts can wear out over time due to age. A failure of the burner or controls can cause a lack of heat, but would not cause a leak from the boiler. It is also possible for a cast iron boiler section to overheat and crack due to a buildup of sludge in the bottom of the section. This sludge can have an insulating effect and cause the metal to overheat, similar to the dry-firing condition.
(Fig. 4 Heavy sludge buildup in boiler section)
Protect the evidence
As you can see, a leaking boiler does not automatically equate to a specific cause of loss. In order to determine the cause of loss, the boiler components must be carefully inspected to consider the possible scenarios. If the damage is discovered during startup in the fall, it may be possible to delay repair or replacement for a few days in order to accommodate an inspection.
In the case of a boiler loss that occurs during the middle of the winter, quick replacement is imperative in order to maintain heat for the residents, prevent pipes from freezing, etc. In that case, the boiler should be repaired or replaced as soon as possible, but the insured and contractor should be instructed to leave all components of the boiler on site for inspection. Inspection of the low water cutoff switches is critical to the analysis, so those must be protected along with all boiler sections.
Questions to ask of the insured
During the course of our analysis of a boiler claim, a few common questions arise:
What is the age of the boiler?
What are the insured’s maintenance procedures? Daily, weekly, annual maintenance? Do any records exist? Who does the work?
When is the last time the boiler low water cutoff switches were blown down? Did the burner shut off at that time?
When is the last time the boiler was cleaned and serviced?
Has there been any prior history of problems?
These questions and more are asked to help determine if the proper maintenance procedures are followed and how that relates to the cause of loss and coverage.
I hope you found this information useful in streamlining the evaluation of your boiler claims. If you have any questions, please feel free to contact Amset Technical Consulting and find out how we can help.
About the author:
Eric Dempsey, PE, CFEI, CVFI Sr. Technical Loss Consultant
Eric Dempsey holds a Bachelor of Science degree in Mechanical Engineering from Iowa State University, and has been with Amset since 2007. Eric has prior experience with designing stainless steel storage tanks and ASME code pressure vessels for a custom tank manufacturer. Eric has extensive knowledge in manufacturing, cost-benefit analysis, investigative procedures, piping systems, and more. Eric’s natural inquisitiveness and hands-on approach to problem solving give him the ability to diagnose a wide variety of problems with all types of mechanical and electrical equipment. His unique approach to disseminating the facts has saved his clients both time and money on countless claims.
Eric is a Certified Fire and Explosion Investigator (CFEI) and a Certified Vehicle Fire Investigator (CVFI) through the National Association of Fire Investigators (NAFI). Eric’s professional memberships include the National Association of Fire Investigators (NAFI) and the Illinois Society of Professional Engineers (ISPE).