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An eight-unit apartment house in San Francisco solved a problem with hot water delivery by installing two American Standard Water Heaters to replace an aging and faltering boiler.

Some Like It Hot

July 22, 2022
Contractor solves hot water challenge for century-old San Francisco apartment building.
Centuries-old buildings in urban areas pose real challenges when it comes time for an upgrade in thermal comfort. The age of the boilers, limited workspace and difficulty in accessing equipment make for a long day in the office for most plumbers.

That was the prospect faced by Excalibur Water Heaters in an apartment building remodel in San Francisco. The small eight-unit apartment house—each unit is 1-bedroom, 1-bath—used a steam boiler to provide hot water and radiant heat. “Because of the age of the boiler, the hot water was never reliable,’’ said Anthony Achermann, one of the owners of Excalibur.

Replacing the steam boiler, however, would have required a months-long wait. Many repair technicians also avoid a challenging boiler replacement project. “Most plumbers in this industry when they see a boiler, they run,’’ Achermann said. “Boiler service people are few and far between these days. Retrofitting any building with a boiler is hard.”

Excalibur designed a solution that solved the problem in just one workday. The company installed two American Standard Water Heaters to provide hot water to the building. Due to the height clearance and width of the installation space, Achermann’s team used two 50-gallon tanks instead of one 100-gallon tank.

Aging System

The system in place at the 100-year old building included a giant steam boiler. “It was about the size of a MINI Cooper,’’ Achermann said. The boiler operated on a timer, so hot water availability differed throughout the day. “Sometimes hot water was readily available,’’ Achermann said. “Other times it was lukewarm or no hot water. Any new system would have been hard to retrofit.”

Steam boilers undergo significant stress and like humans, age over time. Poor water chemistry, corrosion, extreme temperature shifts and even the environment where the boiler is installed can contribute to the degradation of a unit.

Caustic embrittlement due to corrosion is a serious form of boiler metal failure. Even worse, chemical attack of the metal is usually undetectable. Failure occurs suddenly, often with catastrophic results.

Even worse, chemical attack of the metal is usually undetectable. Failure occurs suddenly, often with catastrophic results.

The project was part of a remodeling of the apartment house. “The steam boiler was as old as the building,’’ Achermann said. “If they wanted to replace the boiler, they would have had to wait weeks, if not months. It was a common problem, but I’m seeing it less and less. When I come into a situation like this, I try to identify an out-of-the-box solution that can solve the problem.”

Independent Solutions

Achermann solved the issue by decoupling the boiler from providing radiant heat and hot water. The in-place boiler still runs the heating system for the apartment house, but his team installed two American Standard Water Heaters for the building’s hot water.

Because of space issues, Excalibur installed two 50-gallon tanks. “We didn’t have the space or the height clearance to install a 100-gallon tank,’’ Achermann said. “It was a pretty tight fit.”

The durability and warranty of the American Standard Water Heater brand were important to their inclusion in the project. “Over the years, water heaters have been getting lighter, they are making the walls on many brands thinner,’’ Achermann said. “Over time, water will try to corrode the tank. Anode rods are supposed to prevent that, but eventually they’ll leak and fall apart. The water doesn’t have any where to go, and it leads to leaks. By having a heavier tank, it’s buying more time.”

The warranty also factored into the selection for the project. “With many manufacturers, the water heaters just make it past the warranty,’’ Achermann said. “The American Standard Water Heaters last well past their warranty date. They are also the only manufacturer in the San Francisco area that uses a mechanical gas control valve.”

The durability of the gas control valve was also a consideration for Achermann’s selection of American Standard Water Heaters for the project. “It’s a very traditional burner assembly that has been in use for the past 60 years,’’ he said. “Many have switched to electronic assemblies. The electronic ones are harder to repair, while the mechanical heaters are much more robust overall. I was getting tired of explaining why a unit we installed two years ago was failing.”

Dangerous Decoupling

One of the most difficult, and dangerous, tasks for the project involved separating the boiler and installing the water heaters. With the gas and water lines coming into the building, the team took extreme care to complete a smooth transition.

“It’s important to understand the severity of what could happen if something goes awry,’’ Achermann said. “If something goes wrong, it could create a pressurized vessel that can cause an explosion. We had to make sure the steam radiators work appropriately, and that the boiler only has to make the steam.”

Workers completed the 10-hour project safely, and tenants celebrated that consistent hot water would flow to their apartments without interruption.

“It was a very old system, but that’s essentially how it worked back then,’’ Achermann said. “When radiators are hot, you’ll get hot water. But if it’s 80 degrees, you don’t need your radiators. You’re not going to get your hot water very quickly or efficiently.

“They’re excited because they now have consistent hot water,’’ Achermann added. “Sometimes it would take three-four minutes. We installed a recirculation pump and now the water gets hot within seconds.”

Many older buildings have similar systems, but the products installed by Excalibur make for a far more efficient water heating solution. “It was a project that required some creativity as to how we could solve the problem,’’ Achermann said. “We came up with a good concept and the owner and the tenants are happy.”

Thomas Renner writes on trade industry topics for publications throughout the United States.

About the Author

Thomas Renner

Thomas Renner has produced award-winning journalism for more than 40 years. After a long career in the newspaper industry, Mr. Renner now writes on architecture, building, engineering and other trade industry topics for publications throughout the United States.

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