According to the manufacturer, this furnace is different from others on the market because it has the capability to fully modulate its capacity. It provides a low, or first stage, capacity of 40 percent, which is used during mild days when full furnace operation is not required to heat the conditioned space. Application with a single-stage thermostat provides three-stage furnace operation, while a two-stage thermostat provides what Rheem has termed "quasi-modulation."

The company said the furnace works well in retrofit or new construction applications and installs just like any other Rheem or Ruud 90-Plus gas furnace.

Fedders (www.fedders.com) displayed its 90-percent-plus high-efficiency series, which is designed to use the heat that other furnaces waste, the company stated. Available in upflow, downflow, and horizontal configurations, the furnace control module features self-diagnostics and monitors all furnace functions for reliable operation, said the company. The furnace is less than 40 inches tall, and accessory terminals are provided for humidifiers and electronic air cleaners.

The heat exchanger is constructed of heavy aluminized steel joined to stainless steel in a weld-free process. Most parts are made from either galvanized or aluminized steel. Propane kits are available, and conversion to LP or natural gas can occur in 10 minutes, stated the manufacturer.

Nordyne (www.nordyne.com) featured its new Maytag M1010 product line. The Model PGF1TA high-efficiency 80-percent-plus upflow/horizontal two-stage gas furnace with variable-speed blower may be installed free standing in a utility room, basement, or enclosed in a closet. A fixed 30-second blower delay at burner start-up is designed to ensure a warm duct temperature at furnace start-up. According to the manufacturer, the furnace is quiet due to the unique design of in-shot burners, location of the inducer, and use of insulation.

The Model PGF1TC and PGF1TL high-efficiency 90-percent-plus direct-vent or nondirect-vent condensing furnace features the SmartStart control board, which is programmed to learn the heat-up characteristics of the ignitor, then adapt the ignition time to the characteristics of the furnace. A variable-speed blower maximizes air conditioner and heat pump efficiencies, and selected units have SEER ratings of up to 16 and HSPF ratings up to 8.5.

Nutech Energy Systems (www.lifebreath.com) displayed its Clean Air Furnace, which combines the fresh air benefits of a heat recovery ventilator with the comfort and efficiency of the water heater/air handler. According to spokesman Peter Kendall, this combination heating system provides constant ventilation and a steady stream of warm air for the most comfortable home environment possible.

Unlike conventional furnaces, the Clean Air Furnace receives its energy from a domestic water heater. The company said that since a second flue is not required for the furnace, installation costs can be lowered. The furnace contains an aluminum heat exchanger core and can be equipped with an energy recovery core for southern areas of the United States.

Texas Furnace LLC (www.texasfurnace.com) showcased its Meridian line of 90-percent-plus up-flow, downflow, and horizontal furnaces. These furnaces feature

a computer-enhanced design and are less than 40 inches tall. Spokesman Jerry Godfrey said the furnaces are quick and easy to install, and the powerful four-speed split capacitor blower motor operates quietly, yet easily provides all the air volume needed to meet heating needs.

The company also highlighted its 80-percent, all-position furnace - upflow, downflow, or horizontal. It is available from 40,000 to 140,000 Btuh and 1.5 through 5.5 tons of airflow. The all-position heat exchanger and burner system provide quiet heating, and every furnace is test fired and must pass 34 computer checks before leaving the factory, stated the company.

Williams Comfort Products (www.williamscomfortprod.com) featured its line of vent-free heaters. The company said these units feature a contemporary, white powder-coat scratch-resistant finish to blend with any decor. An oxygen depletion sensor monitors room oxygen levels for safe operation. According to the manufacturer, no electricity or venting is required, and a heavy-duty, quiet blower is available for larger rooms, where faster heat circulation is desired.

Meanwhile, Texas Instruments Sensors and Controls (www.ti.com/snc) introduced its DiagnosTECHâ„¢, a gas furnace integrated ignition control panel designed to deliver advanced control features with fault code retention capability. According to the company, the new control offers enhanced functions and communications that interfaces with a PDA "to simplify maintenance and repair calls." The product earned an honorable mention in the 2004 AHR Expo Innovation Awards.

"DiagnosTECH is built on a platform so that an OEM can select the set of features to fit their needs - ultimately constructing an efficient, cost-savings custom solution," said Jim McGuinness, marketing manager.

Sidebar: ...And There Were Oil Furnaces, Too

According to Director of Product Management Dick Hanna, the front-flue models feature a flue collector box that can be serviced without removal. The units also offer side knockouts for installation in homes with old chimneys; the knockouts can help the installer gain up to 12 inches in space.

The rugged cabinet is made of prepainted, heavy-gauge materials, the same as outdoor units, Hanna said. All electrical connections are plug-ins and polarized. The combination chamber mounting assembly is removable for easier inspections.

ECR International (www.olsenhvac.com) showed its Airco high-efficiency residential oil furnaces. The lowboy series can achieve up to 85.1-percent efficiency due to its heat exchanger design, high-performance oil burners, and fiber-reinforced, foil-faced cabinet insulation.

The furnace has a completely insulated combustion chamber to provide quiet operation and clean-burning performance, the company said. The oil burner is equipped with a solenoid oil valve for clean starts and quiet shutdowns. The furnaces feature 100-percent welded, heavy steel-gauge heat exchangers, multispeed blowers, high-quality motors, and 20-gauge panels with a baked-on, epoxy-based powder coating. Direct sidewall venting is possible.

- B. Checket-Hanks

Publication date: 03/01/2004