Water heaters are one of the least glamorous types of home appliances. The vertical metal tanks typically sit out of sight in dark corners of basements or behind closet doors. Most homeowners never think about the devices—until there’s no hot water. Just ask anyone who’s ever been forced to take a cold shower.
A variety of manufacturers produce electric and hot water heaters for residential applications, including GE Appliances, a Haier company. To increase production capacity, it recently invested $70 million in a state-of-the-art manufacturing plant in Camden, SC. The 265,000-square-foot facility also serves as the company’s Center of Excellence for water heater manufacturing.
The building originally housed a Haier refrigerator factory that opened in 2000. At the time, it was the first Chinese company to establish a manufacturing operation in the United States. Haier acquired General Electric’s appliance division for $5.6 billion in 2016. Part of the deal was a long-term agreement to continue use of the GE name, including its famous monogram logo.
After deciding to become more active in the water heater market, GE Appliance management earmarked the Camden plant for a massive renovation and retooling effort. The investment included advanced systems for metal fabrication and welding, plus robots for material handling and processing.
“We cleared out all of the existing equipment all the way down to the concrete floor,” says Tom Zimmer, executive director of water heating for GE Appliances. “Then, we built a state-of-the-art factory that’s one of the first new gas water heater plants built in the U.S. in decades.”
Zimmer and his colleagues used cutting-edge tools to reconfigure the facility for efficient production.
“GE Appliances has spent the last six years investing more than $2 billion in technology and our U.S. plants and operations,” explains Zimmer. “Lessons learned and advancements from every product line and manufacturing operation we’ve launched were used to develop our new facility in Camden. We also applied new technologies and techniques developed in other industries to create the very best manufacturing operation possible.
“GE Appliances has a clear perspective on the importance of producing top quality, high performing products, and a key to doing that is designing factories that allow our production team to safely and efficiently manufacture those products,” Zimmer points out. “With a long history of continuous improvement in both products and production operations, this new plant gave us the canvas to create a true world-class operation for manufacturing our water heaters.
“This center of excellence is extremely flexible in how we can produce down to single unit requirements,” claims Zimmer. “Flexibility provides us the capability to produce efficiently and vary the operation to produce what is needed, when it is needed, to meet customer demands."
GE Appliances’ engineers carefully considered quality, safety and ease of manufacturing when designing and laying out the plant. "Automation was selected to provide predictable, consistent quality of products in an environment that is safe and ergonomically friendly to our operations team," explains Zimmer.
The old plant was redesigned into a modern facility using a variety of six sigma tools and lean manufacturing principles. “We also used simulation software to evaluate workflow and see how parts and processes would interact with operators,” says Frank Scheffel, the plant manager who oversaw the transformation from electric refrigerators to gas water heaters.
“We worked with operators at the Camden plant, along with engineers at GE Appliances’ corporate headquarters in Louisville,” explains Scheffel. “The first thing we did was split up into three teams to figure out the best way to lay out the plant for water heater production.
“We focused on creating a production process centered around operators,” says Scheffel. “We looked at different approaches to ensure the best way to present parts from an ease of access point of view. We paid special attention to ergonomics to ensure there were zero ‘ergo red’ jobs on the plant floor.
“In addition, the other big consideration was the efficient flow of material through the plant,” notes Scheffel. “For instance, we made the final assembly line a forklift-free zone. All materials are delivered to workstations with automated guided vehicles and tuggers.”
“Vertical integration allows [us] to meet our customer demands while managing supply chain variation, controlling cost and delivering high quality extremely well every single shift,” says Zimmer.
“Vertical integration gives us unique flexibility,” adds Scheffel. “We start with raw coils of steel and stamp out the major components of the tanks, which include the sides and a beveled top and bottom, plus smaller sheet metal parts. It gives us the flexibility to change over production throughout the day, if necessary.
“The refrigerator factory was vertically integrated, but not to the same degree as with the water heater products,” explains Scheffel. “Now, we try to either make it ourselves or buy from U.S. suppliers.
“When reconfiguring the new plant, we treated it as two halves,” says Scheffel. “The back half of the factory is the fabrication area that roll forms coils of steel into tanks, then automatically welds the seams. This part of the plant also includes leak testing and a paint shop. The front half of the factory consists of assembly lines, plus test, inspection and packaging.”
Hot water heaters are different than refrigerators, washing machines and other household appliances.
“Water heaters are a long-life, unattended product in most homes, which is expected to perform every day without issue for a decade or longer,” explains Zimmer. This means that reliability is key to meeting customer expectations.
“Water heaters themselves are constructed with heavy gage metal materials requiring expertise in many production operations which are unique for these products, including welding, porcelain enameling, insulating and leak testing,” adds Zimmer.
While electric and gas water heaters look similar, there are some subtle differences. For example, gas products have a few more components than electric models. The primary difference is a burner assembly that’s positioned at the bottom of the tank to heat water.
It’s contained in a separate component called a combustion chamber that’s assembled apart from the tank. The tank contains a flue pipe that runs up through its center to exchange heat into the water. The pipe contains a baffle made out of welded sheet metal.
“The base construction of an electric water heater is a little easier to produce,” says Zimmer. “Gas hot water heaters are a more challenging product to build consistently. Unlike electric alternatives, there are FVIR (flammable vapor ignition-resistant) requirements that are based on an ANSI safety standard.
“A water heater is less complex than the majority of appliances that we make,” explains Zimmer. “However, while it has fewer components, it’s more difficult to manufacture, because you have to make a leak-free tank that prevents corrosion from the gallons of water that sit inside it for many years. There are also multiple ports in the tank for things such as drain valves, pressure-release valves and inlet-outlet nipples.
“Those are things that we didn’t have to contend with on the refrigeration products previously made in the plant,” Scheffel points out. “It provided an interesting twist on things that required special operator training. For instance, the ports that various components go into are pipe threads. Sometimes, they can be rough and difficult to seal.
“We leak test every tank before it goes to the assembly line, using air pressure and soapy water,” says Scheffel. “We also have an end-of-line quality process that ensures that [threaded] components are installed correctly and aren’t over- or under-torqued.”
The Camden plant features one main assembly line. But, a flexible, mixed-model process enables it to produce multiple tank sizes at the same time. The facility can build both natural gas and liquid propane products on the same assembly line and test each variety.
Assemblers produce six different tank sizes that are available in either tall or short versions. They hold 30, 40 and 50 gallons of water, depending on the type of model. All tanks are painted a standard gray color, but there are three different warranty levels, based on the types of components that are attached.
Every tank body starts with a roll form. Then, ports and the top of the tank are automatically welded. Finished subassemblies are transferred to an overhead monorail conveyor.
The flue and bottom head assemblies are joined together on a separate welding line, then transferred by another overhead conveyor to a spray enamel process. Finally, tanks are transferred via robot to a conveyor that runs through a furnace to cure the enamel.
At the end of the fabrication process, each tank undergoes leak testing. All pressurized tests are done on an indexing drag chain-type conveyor.
The main assembly area uses another indexing conveyor. Each tank is introduced in an upright position, but then repositioned horizontally so that operators can press-fit the combustion chamber to the bottom. Once that’s in place, fiberglass insulation is inserted around it.
“Next, we upright the tanks onto a base pad,” says Scheffel. “The tanks ride vertically on a flat roller conveyor the rest of the way down the assembly line. A water heater is similar to a refrigerator in that regard, because it’s a tall appliance.
“To address ergonomic concerns, we divide up work into low, medium or high tasks with respect to the product,” explains Scheffel. “Then, we position operators to get them in the right ergonomic position so that they interact with the tank at an ergonomically correct height.
“We also use very few exterior fasteners on the assembly line,” adds Scheffel. “In fact, the only visible screws are used to build the burner assembly and to attach it to the combustion chamber using DC-electric fastening tools.”
When it reaches the end of the assembly line, the typical gas water heater weighs about 150 pounds.
“The size, weight and configuration of the tanks made automation a necessity for operator safety and ergonomics,” says Zimmer. “The plant is equipped with more than 35 robots, with the majority of them located in the fabrication area. They are primarily used for material handling and welding applications.
“But, people are the absolute key to our success,” adds Zimmer. “Our strategy was to empower the Camden team through in-depth training in digital skills, lean manufacturing and soft skills, along with utilizing their production expertise to create an optimal new plant.
“While the refrigerator plant was being reconfigured to produce water heaters, we partnered with Central Carolina Technical College to train many employees on courses related to mechatronics, robotics and welding, plus basic manufacturing principles,” explains Zimmer.
To see a short video of how a gas water heat is assembled at the GE Appliances factory in Camden, SC, click here.