Why Did The Boiler Fail So Quickly?

For a sales transaction to be successful, there has to be certain expectations for both the buyer and the seller. That same type of arrangement holds true when a building owner purchases a boiler.

The owner expects to have a heating system that is trouble-free, efficient, and will last for decades. The designer, installer, and manufacturer expect to be paid in a timely manner for their design, equipment, and installation. There is a further expectation of the owner that is rarely mentioned.  The designer, manufacturer, and installer expect that the owner will maintain the new equipment. When that does not happen, bad things can and will occur.

The following are a couple projects that went south because the equipment was not maintained properly. This may help you on your next boiler project.

Two Pipe The original installer called to tell me that the boilers we sold several years ago were a mess and the owner wanted the installer to replace the boilers for free. Upon arrival, I found the installer was telling the truth. The tubes were filled with rust, the insulation had black mold, and the boiler jacket had rust streaks. The system was a two pipe system which used either hot water or chilled water. The owner never isolated the boilers during the cooling season and chilled water flowed through the boilers for the past four years. The boilers were ruined.

Low-Water Cutoff The text from my friend asked that I call him right away, saying it was important.  When I called, he told me that the two year old cast iron steam boiler he installed had suffered a major failure. The boiler dry fired and was ruined. The cause of the failure was the owner never blew down or even checked the low water cutoffs. The interior of the low water cutoffs were filled with mud holding the internal float in place, fooling the boiler into thinking it was full of water. The low water cutoff is the leading mechanical cause for boiler failures. Luckily, the system did not explode and there were no injuries but the two year old boiler was ruined.  

Thermal Shock The maintenance director of the university informed me that the cast iron sectional boiler kept cracking sections and was blaming the boiler manufacturer. I found that the boiler was only about two thirds the original size as the owner kept removing the damaged sections and shortening the boiler. The owner never changed the firing rate of the burner so it was grossly oversized for the now shortened boiler. In addition, the blend pump which was supposed to help to avoid thermal shock that the boiler was experiencing was inoperable.

Water Temperature “One of the new boilers is leaking” was the call I received on a Monday morning. The “new boiler” was actually 6 years old. I saw excessive rust on the fireside of the boiler. I checked the control set points and was amazed the damage was not worse. The boiler operating control was set for 140 degrees F and the reset control was set down to 90 degrees F. The loop temperature on that day was 110 degrees F. I asked how the controls got so far out and he shrugged his shoulders and then asked if it was covered under warranty and it was not. If a standard boiler is operated below 140 degrees, the flue gases will condense and acids will eat away the fireside of the boiler.

pH The four year old boiler had a pin hole in the top of the casting. When I checked the pH in the water, it was at 12.0. The boiler manufacturer stipulated that the pH should be between 6.5 and 8.5. Although the 3.5 difference between the actual reading and highest level seems insignificant, it is actually very large. PH readings are logarithmic which means that a difference of 1 means the difference is really ten times different. A difference of 2 means that that the difference between the two is 100 times. The 3.5 difference means that that actual pH reading was 5,000 more caustic than the manufacturer stipulated. When the water is caustic, it could cause scale buildup and even caustic embrittlement which will destroy the boiler. In addition, the water treatment company did not realize that the boiler was an aluminum boiler which would require a different type of water treatment.

Oversized We were in the boiler room to service the leaking circulator pump when I walked behind the boiler looking for isolation valves and saw the condition of the flue. It was peppered with small in holes and rust trails. The boiler has small piles of rust under the draft diverter. The boiler was so oversized that the chimney never had a chance to warm the flue. It would short cycle and flue gases would condense. The flue had to be replaced.    

Boiler maintenance or lack thereof is the leading cause of boiler failures. In my area, there are roughly 4,000 heating hours per year. If you equate that to an automobile and that vehicle drives those same 4,000 hours at an average speed of 25 miles per hour, the vehicle would have 100,000 miles that first year and 200,000 miles by year two. Could you imagine driving an auto for that many miles without doing any maintenance? 

Lack of boiler maintenance has been a common issue and leads to shortened equipment life and dangerous conditions. As a matter of fact, the ASME CSD1 CM-110 code recognizes the problem and stipulates the following:

…a systematic and thorough maintenance program shall be established and performed.

… results shall be recorded in a boiler log, maintenance record, service invoice, or other written record.

Any defects found  shall be brought to the attention of the boiler owner and shall be corrected immediately.

CM-120 The qualified individual performing inspections and tests shall be trained and familiar with all operating procedures…

There are a couple things that should be done to make sure the boiler has a long life.

• Perform regular maintenance on the boiler.
• Do not operate the boiler outside of its design parameters.
• Have the boiler inspected regularly.

I realize that many facilities do not have the budget or individuals that can service the boilers. The irony is that they do not have the money for maintenance but somehow find the funds to prematurely replace the equipment. Perhaps it is time for the engineers and installers to offer an extended maintenance agreement with the new equipment or the maintenance organizations need to show people the ASME CSD1 code and adhere to it.

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