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This article will take a look at three special projects that involved hydronic heating and how each contractor solved his client’s problem by choosing the proper design and equipment for each job — and how these jobs may give other HVAC contractors some insight into how they can sell wet heat to their own clients.
John Cataneo, owner of Gateway Plumbing and Heating of New York City, had a real challenge on his hands. His client owned a 10-unit Brooklyn apartment building which was heated by an old, inefficient oil boiler that continually needed repair, costing a lot to operate.
Cataneo’s solution was to install a high-efficiency modulating-condensing boiler with new distribution piping. His crew brought in the new, high-efficiency boilers and indoor/outdoor temperature sensors and controls. Gateway then installed all new piping, piping supports, and insulation, as well as a new utility sink for servicemen to clean the boilers and service parts.
The result? “The owners were extremely pleased with the results, especially since there was a drop in fuel costs no one was prepared for,” said Cataneo. “One of the apartment renters is a very technical person who keeps a log of the boilers’ functions.
“Among other things, there is a chart maintained daily showing the outdoor temperatures and boiler supply water temperature. In all of the first winter, the system shows never having to raise the water temperature higher than 146˚F, even in 9˚ weather.
“Dropping the water temperature by 36˚ saved over $6,000 in fuel costs; three-fourths of the way into the heating season alone. I’m proud of that efficiency gain.
“Thankfully, the newest modulating-condensing (mod-con) boilers are the key to creating a nearly foolproof high-efficiency hydronic installation. Designers need to remember that flow rates and distribution methods are critical; and outdoor reset parameters are to be set with utmost care.”
Cataneo had a lot of help from manufacturers along the way, too. “Triangle Tube, Caleffi, and Tekmar (the control system) provided their approval on our design,” he said. “Taco provided model numbers for pumps based on our flow calculations.”
A Tight Fit
Paul Pollets is no stranger to challenges. The owner of Advanced Radiant Technology (ART), Seattle, enjoys designing and installing hydronic equipment that tests his expertise and training. One such job was the Brossmann project.
“We began the Brossmann project as a boiler replacement,” said Pollets. “It turned into a major heating renovation project when the owners decided to make the home a comfort dream, coupled with energy efficiency. The boiler system we replaced had failed prematurely, due to improper installation.”
The first and major challenge of the job was fitting new equipment in the tiny basement mechanical room (4-foot by 7-foot closet.) “It required careful planning to fit all the goodies in such a small space,” said Pollets. “The Viessmann Vitodens boiler is the heat source using a VitoCell V300-79g indirect DHW tank for ample domestic hot water. This family has high domestic hot water [DHW] usage with two adults and six children (and guests). We sized the tank accordingly and there are no complaints that the shower’s too cold.”
The owners also had ART replace all of the heating circuits in the home and install several zones of radiant floor heating using Wirsbo™ QuickTrak™ panels and Oventrop UniBox controllers.
Pollets and his crew also installed Runtal wall panel radiators and Towel Bar Warmers. ART future piped for a solar DHW vacuum tube rooftop array to supplement the tank when the solar tax credits are more favorable.
“Another challenge was adding the main floor radiant mix zone,” Pollets said. “We had completed the system when the owners added the entire main floor as a staple-up application. ART had to fabricate a custom bracket assembly for the mixing station on the VitoCell DHW tank to make it all work when space was non-existent.”
“The home overlooks the Puget Sound and the Olympic mountains. The esthetic of the new system was as important to the Brossmanns as the breathtaking views from the front decks and living room.”
Frank Wilsey goes by the name of “Steamhead” and his company, All Steamed Up of Towson, Md., had a client who was all steamed up about the cost of natural gas to heat a one-pipe system in a five-building complex built in 1915. The problem was one-half of the complex was left with little or no heat while the other half experienced too much heat from boilers which ran for hours.
So Wilsey said he took the “back to basics” approach. “We measured the lengths and diameters of all the steam mains, which took long and tortuous paths through the basement,” he said. “We then counted up all the radiation in the buildings and discovered that the system could run on just one boiler to heat the buildings — and even one was a bit oversized. Both boilers had been fired at the same time for years. The complex always had two boilers but one was supposed to be a spare.”
And then All Steamed Up tackled the project in a series of stages. “Once the venting was done and the Tekmar installed, we installed a water meter on the boiler-feed make-up line,” Wilsey said. “It revealed the system was losing a lot of water. We found this was due to water hammer in the returns that blew some soldered joints apart.
“These were originally wet returns that worked by gravity. This is a one-pipe system but when the present boilers were installed (or maybe afterward) someone installed a boiler-feed tank and pumps. Being typical knuckleheads, they master-trapped the returns right before the tank. This allowed steam to enter the returns where it banged and tore the joints apart. The effects of all that fresh make-up water became clear when the boiler-feed tank rotted out.”
Wilsey and his crew replaced the tank and the return lines. In order to keep the return lines full of water so steam would not enter them; they built two “false” water lines — one for each side of the building. This took care of the water hammer and, as a bonus, reduced the amount of steam needed to fill the system.
“The next phase was to convert the two PowerFlame gas burners to low-high-low firing,” Wilsey said. “Commercial burners must go through pre-purge and post-purge cycles every time they start up and shut down. If they do this while the boiler is hot, as when a steam boiler shuts down on pressure, much heat is lost up the chimney. On a steam system you want to shed the pickup factor and just maintain enough fire to keep everything hot, but you don’t want to drop low enough that the flue gases condense in the chimney. Don’t do this unless you have a digital combustion analyzer and the know-how to use it.
“We contacted PowerFlame and determined what parts were needed to make changes, which is the right way to do anything like this. Don’t even think about doing this type of work unless you get the manufacturer involved.”
The results have been dramatic. “The system’s increased efficiency is obvious,” Wilsey said. “The entire building is being heated instead of just one-third of it. But the gas consumption — as measured in therms per degree-day — has not gone up. It hasn’t gone down either, but we can see they are getting three times the results from the fuel they use.”
Publication date: 2/20/2012