Audel HVAC Fundamentals Volume 1 Heating Systems, Furnaces, and Boilers

Gas Furnaces

This chapter is concerned primarily with introducing the basic proce­dures recommended for installing, operating, servicing, and repairing gas-fired forced-warm-air furnaces. Additional information about furnaces is contained in Chapter 10, “Furnace Fundamentals.” Only gas-fired furnaces approved by the American Gas As­sociation (AGA) should be used in a heating installation. Not only does AGA certification ensure a […]

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Furnace Fundamentals

The American Society of Heating, Refrigerating, and Air — Conditioning Engineers (ASHRAE) defines a furnace as “a com­plete heating unit for transferring heat from fuel being burned to the air supplied to a heating system.” The Standard Handbook for Mechanical Engineers (Baumeister and Marks, seventh edition) provides a definition that differs only slightly from the […]

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Electric Heating Systems

Different heating systems use electricity as a source of heat. Each of them employs one or more of the following methods of heat transfer: 1. Radiation 2. Convection 3. Forced air Radiation is the transmission of heat energy by means of electro­magnetic waves (infrared light). In other words, the heat is transferred directly from the […]

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Steam Heating Systems

Steam is a very effective heating medium. Until recently, this property of steam has resulted in its being the most commonly used method of heating residential, commercial, and industrial buildings. Over the past 40 years or so, steam heating has been largely replaced in res­idences and small buildings by other heating systems that have often […]

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Troubleshooting Hydronic Heating Systems

Most problems associated with hot-water heating systems involve the heating appliance (boiler, water heater, or hydro-air furnace), the water circulation pump, or the automatic controls. Table 7-1 lists some of the more general problems associated with hydronic heating systems. Specific problems involving boilers, water heaters, and auto­matic controls are covered in the appropriate chapters of […]

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Disadvantages of Hydronic Heating Systems

A principal disadvantage of a hot-water (hydronic) heating system is its initial high installation cost when compared to a forced-warm — air heating system. Other commonly cited disadvantages of hydronic heating are: • Stagnant air caused by lack of ventilation (air movement) in radiant heating systems not equipped with cooling. • Comparatively slow heat response. […]

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Advantages of Hydronic Heating Systems

There are several distinct advantages to using hot-water heating as opposed to steam heating. For one thing, hot-water heating is more flexible than low-pressure (above-atmospheric) steam systems because the temperature may be widely varied. Due to the low working temperature of the water, the heat from a hot-water sys­tem is relatively mild, and the room […]

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Electrically Heated Systems

Compact electric boilers, water heaters, or combination water heaters are also available for use in hydronic systems. These boilers are characterized not only by their compactness but also by their quiet operating characteristics. The extreme compactness of an electric hydronic boiler is illus­trated in Figure 7-36. The heat exchanger, expansion tank, and operating controls are […]

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Moisture Control

A hot-water heating system will generally maintain an adequate humidity level without the additional assistance of a separate humidifying unit. The humidifier illustrated in Figure 7-35 is an example of the type that could be used in a hydronic heating system should one be required. It is designed with a hot-water coil on the air […]

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Air Conditioning

For many years hydronic heating systems were installed without any provision for air conditioning. Two important reasons for not including cooling systems were: • The location of the floor-mounted radiators and baseboard convectors would cause the heavier cold air to collect along the floor. • It was impossible to capture and remove the condensation that […]

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