Many of the area’s larger mechanical contractors can’t do these jobs cost-effectively, and some smaller contractors simply don’t want to handle the work. However, Bendler Mechanical has thrived on the rehabilitation of old boilers.

Challenging Work for Technicians

One of the challenges of working with old boilers is that the conditions in which technicians must perform are often less than ideal.

“Back in the 1930s and 1940s, a lot of the boilers had the buildings constructed around them. We have to cut the boilers in pieces to get them out,” says Fish. “Then the new equipment has to be built inside or has to be some of the smaller equipment that fits through a narrow doorway.

“You’re in the dirtiest possible working conditions that you can be in because the dirt’s been there for so long. There is very little lighting, there are few windows, and the stairs are narrow and steep,” says Fish. “It’s tough to find men to work in this business.”

Accumulated dirt in an existing system can wreak havoc on the new equipment, according to Fish. When new boilers are started up, dirt and scale from the old piping contaminates the new boiler and makes it difficult to keep running. To clean out the system, Bendler Mechanical uses a surface skimmer, adds condensate for a couple of weeks, then adds chemicals.

Changeouts Are Tricky

Unfortunately, replacing these boilers is not as simple as swapping out the old for the new. In many cases, the new equipment is no longer compatible with the old setup, and it usually requires changing more than one element of the system.

“The new boilers hold less water, so your return system is different,” says Fish. “The electrical system is also different. Many of the old boilers only took 120 volts to operate, and there’s no high voltage into some of these boiler rooms. We have to determine how we’ll supply power to operate the new boiler.”

Since many of the older boilers are one-pipe systems, feed water tanks often have to be added, according to Myron Bendler. He cautions that when feedwater tanks are added, the system controls must be modified to accommodate the change.

“Sometimes contractors will install feedwater tanks that are too small. With these big old boiler systems, you get too much condensate back during the first hour of running time, and it floods all over the floor,” says Bendler. “You have to take the entire system design into consideration when replacing this equipment.”

Watch Water Quality

Fish notes that the introduction of fresh water to the system should be minimized to reduce scaling and the presence of minerals.

“The more fresh water you have, the more minerals enter the system, and those minerals attack the metal in the boiler and in the rest of the piping,” says Fish. “That’s why we always look at the pump sizes and tank sizes, trying to keep systems from overflowing in order to keep the fresh water intake to a minimum.”

One of the biggest problems with replacing these boilers, say Bendler and Fish, is that contractors don’t always follow the manufacturer’s instructions regarding the size and placement of piping to the boiler. The placement of header piping on a cast-iron boiler is particularly critical, and incorrect installation can affect the quality of steam and the efficiency of the system.

“When you follow the manufacturer’s instructions as far as pipe sizing on the boiler proper, it will work correctly as long as the water chemistry is where it should be,” says Bendler.

Controlling the New Equipment

Once the new equipment is installed, a building’s energy management system (if it has one) should be carefully adjusted to run the boilers properly.

Although building management systems are designed to save the owner money, they can actually cost more in fuel costs, boiler repairs, and chemical supplies if they’re not adjusted properly, according to Bendler and Fish.

“Some of these systems will try to save money by shutting the boilers off a certain amount of time every day,” says Fish. “But sometimes a boiler needs to run almost full time just to stay warm and keep the water level constant, and that reduces fuel used and saves the cool water makeup by shutting off the cycle.”

Not all older boilers have to be completely replaced to obtain good efficiency if they’ve been well maintained, according to Bendler.

“With some of the new equipment available, you can update some of these old boilers and still get good efficiency out of them,” says Bendler. “You don’t have to just yank them out.”

Sidebar: Rubber and Ready-Mix Provide Niche Markets

Although many companies struggle to find the path to success in their respective industries, Bendler Mechanical has excelled in a couple of boiler-related niches in the hvac industry. The small mechanical contractor specializes in servicing process boiler systems that produce high-pressure steam and hot water for industrial processing plants.

Bendler builds process boiler systems for companies that vulcanize rubber into automobile tires, belts, hoses, and other products. These plants rely on high-pressure steam to operate their processing equipment.

“The challenge with high-pressure steam is very simple,” says Myron Bendler, president of the company. “The steam has to get to the equipment so that it can do its job, and the condensate has to return to the boiler plant.”

Despite the simplicity of the concept, processing plants pose a unique challenge because they are frequently spread out over a large area: Steam often has to travel a great distance to reach all of the equipment. Regardless of the distance traveled, the steam still has to be hot and dry when it reaches its destination.

The system must have correctly sized pipes and traps and proper steam control valves and insulation to work effectively. Correct pipe pitching is important, too, in producing a drier steam with less carryover.

Bendler Mechanical also services process boiler systems in ready-mix concrete plants, which generate tremendous amounts of hot water in short periods of time to produce concrete. Many contractors, Bendler says, don’t know how to make hot water fast enough to keep the plants running.

“How do you make 5,000 gallons of 200°F water in one hour, and still keep the equipment functional, without all of the lime build-up and scale and without shutting down anything?” asks Bendler. “We do that with certain types of equipment.”

His company has succeeded by using steam boilers and heat exchangers that have tubes constructed of special alloys in lieu of copper. Since the equipment is handling large volumes of water and working around the clock, most of it is oversized to accommodate the fouling that occurs even with the best equipment.

Bendler estimates that his company services between 40 and 50 ready-mix concrete plants in the St. Louis area.

Publication date: 09/04/2000