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HI 750 G, the Preferred Temporary Heating Solution

(Waukesha, WI) In business for 105 years, Hunzinger Construction Company is one of the Midwest’s oldest and most experienced contracting firms. Located in Brookfield, Wis., this top “green” contractor offers its customers construction management, general contracting and design/build services. It is known for building some of Milwaukee’s famed locations like Miller Park, the Midwest Airlines Center and the U.S. Bank Center.

One of the company’s recent quick turnaround projects in September 2011 included total reconstruction of an engineering office space for GE Energy Systems in Waukesha. The contract included drywall, painting and carpeting throughout the 24,000 ft2 office space. In total, 40 skilled laborers worked on completing the project.

Contract deadline was the end of 2011, requiring the trades to work during the cold Wisconsin winter months. “We removed the old HVAC system and installed new, so we needed temporary heat for the workspace,” explains Von Vandreel, field superintendent for Hunzinger Construction Company.

Vandreel worked with Mark Rummler and Steve Ransom with Lincoln Contractors Supply (LCS), the Wacker Neuson dealer in Waukesha. “We’ve worked with Lincoln for years, and they are a great company,” says Vandreel. “They offered us three different heating options, and everything on our checklist led us to the HI 750.”

Clean and Dry Heat
Since crews were installing drywall and painting in an enclosed office space, they required clean and dry heat. With significant detriments associated with the direct fired heater combustion process, this immediately took this heating solution out of the equation.

Steve Ransom, Waukesha territory Manager for LCS, explains, “The open flame inside the workspace creates a safety concern. These heaters burn oxygen and produce carbon monoxide and dioxide, which can affect workers in the heated area. The flame also introduces moisture into the workspace, which lengthens the drying time for drywall mud and paint.”

With different trades working on the renovation project, any scheduling interruptions due to increased drying time for drywall mud or paint could cause a ripple effect of delays that extents the project beyond its deadline.

Direct fired heaters can also have an impact on air and project quality standards. “Increased moisture inside the work area promotes mold growth that can trigger respiratory issues,” says Dave Mencel, Climate Technology product manager for Wacker Neuson. “Additionally, diesel units produce a soot by-product, which can stain paint and leave a residual odor inside the work area.”

Vandreel’s final decision came down to hydronic heat with heat exchangers or the HI 750 G indirect fired heater from Wacker Neuson. Hydronic heat requires the use of heat exchangers and hoses placed inside the work area, which was a problem. “We needed dry heat, but I didn’t want to work around glycol hoses or mess with moving around heat exchangers,” Vandreel says.

The HI 750 G was the right solution for Hunzinger’s needs. Crews positioned the heater at ground level on the sidewalk outside the building. “The HI 750 G offers simple, two-person set-up for us, and it is quickly ready for the contractor to use once onsite,” says Ransom. Vandreel adds, “It was the simplest solution for us.”

Technicians quickly hooked up 220- and 110-volt lines to the heater and ran a hardline from the building for the natural gas fuel source. Hunzinger’s HI 750 G was equipped to run on natural gas or LP fuel. However, the HI 750 Series indirect fired heaters also feature an optional “plug and play” burner kit. Offering more flexibility in the field, this provides quick and simple conversion between diesel and natural gas or LP.

Hunzinger’s crews cut three 16-in diameter duct holes into a piece of plywood to channel the clean, dry air from the heating unit through a window to the building’s second level, where renovation took place. Vandreel mentions that they ran the main duct right down the center of the space. “The other two flexible ducts ran along the walls of either side of the building,” he says. A HEPA filter attached at the end of the duct runs helped to distribute the heat. 

The structure’s 13-ft high ceilings required a heater that could provide enough energy and airflow to heat the 312,000 ft3 space. The Wacker Neuson HI 750 G delivers 622,500 BTU/hr heat output to efficiently heat up to 1,009,000 ft3 spaces, so it had plenty of heating capacity. “We kept the heater running wide open, and it was warm enough to work in t-shirts,” mentions Vandreel.

Even though this heater was operated continuously without the aid of a thermostat, the HI 750 G’s exclusive Recircul-Air design helped improve fuel efficiency. “This unique Wacker Neuson feature allows adjustable recirculation of warm inside air, while pressurizing with fresh air, to save on fuel and create more uniform temperatures throughout the structure,” says Mencel.

This gives Hunzinger the best of both worlds for quickly completing the GE renovation project. It recirculates a percentage of heated inside air to reduce fuel consumption while introducing fresh and dry heated air from the outside to reduce drying time for drywall mud and paint.

The clean and dry temporary heat provided by the HI 750 G kept the trades on schedule and working through those cold December days. “We are very happy with the performance of the HI 750,” concludes Vandreel. “It was low maintenance and got the job done. We will use it again.”