2)Large Water Volume Systems - The piping shown in Figure 13 will minimize the amount of time that the boiler operates with return temperatures below 120°F on these systems. A bypass is installed as shown to divert some supply water directly into the return water. The bypass pipe should be the same size as the supply. The two throttling valves shown are adjusted so that the return temperature rises above 120°F during the first few minutes of operation. A three-way valve can be substituted for the two throttling valves shown. If the circulator is mounted on the supply, the bypass must be on the discharge side of the circulator.

3)Low Temperature Systems - Some systems, such as radiant tubing systems, require the system water temperature to be limited to a value below the temperature of the water leaving the AWI or TWI. These systems also typically have return temperatures well below the 120°F minimum.

Figure 14 illustrates the use of a heat exchanger to connect the AWI or TWI boiler to this type of system. The heat exchanger will permit the transfer of heat from the boiler water to the low temperature system while holding the system supply and boiler return temperatures within their limits. For this system to work properly the heat exchanger must be properly sized and the correct flow rates are required on either side of the heat exchanger. Consult the heat exchanger manufacturer for sizing information. The water in the boiler is completely isolated from the water in the system. This means that separate fill and expansion tanks are required for the heating system loop.

There are several other ways to connect low temperature systems to the non-condensing boilers like the AWI or TWI such as four way mixing valve and variable speed injection pumping systems.

4)Systems containing oxygen - Many hydronic systems contain enough dissolved oxygen to cause severe corrosion damage to a cast iron boiler such as the AWI or TWI. Some examples include:

•Radiant systems that employ tubing without an oxygen barrier.

•Systems with routine additions of fresh water.

•Systems which are open to the atmosphere.

If the boiler is to be used in such a system, it must be separated from the oxygenated water being heated with a heat exchanger as shown in Figure 14.

Consult the heat exchanger manufacturer for proper heat exchanger sizing as well as flow and temperature requirements. All components on the oxygenated side of the heat exchanger, such as the pump and expansion tank, must be designed for use in oxygenated water.

FIGURE 12: INDIRECT WATER HEATER

BOILER SIDE PIPING

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Crown Boiler TWI162, TWI095, TWI128, TWI061, AWI061, AWI195, AWI162, AWI229, AWI262, AWI037, AWI128, AWI095 Indirect Water Heater
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AWI262, AWI095, TWI095, AWI195, AWI037 specifications

Crown Boiler is a renowned name in the heating industry, providing high-quality, efficient heating solutions that cater to various residential and commercial needs. Among its impressive lineup, the AWI and TWI series stand out for their design, technology, and performance.

The Crown Boiler AWI061 and TWI061 are part of the Hydronic Boiler range, designed to deliver efficient hot water heating. The AWI series features an advanced pressure-jet design that allows it to operate with exceptional fuel efficiency, reducing operating costs for homeowners and businesses alike. Additionally, these models come equipped with an integrated pump system that ensures a consistent supply of hot water, making them ideal for both space heating and domestic hot water applications.

Meanwhile, the AWI162 and AWI128 models are engineered for higher output, addressing larger heating needs without compromising efficiency. These models showcase a robust heat exchanger made of durable cast iron, promoting longevity and effective heat transfer. The AWI series boilers feature a modern control system that allows for precise temperature management, enhancing comfort while minimizing energy consumption.

The Crown Boiler AWI295, on the other hand, steps up with a significant heating capacity suited for commercial applications. This model is designed with advanced safety and efficiency technologies, including an intelligent control module that monitors temperature and pressure, ensuring optimal performance while preventing malfunctions. The large water volume design allows for enhanced thermal stability and consistent heating output.

A notable characteristic across these models is their ease of installation and maintenance. Crown Boiler has engineered the units with user-friendly features, including accessible components and simplified diagnostics that help technicians service the boilers swiftly. Moreover, the durability of cast iron construction ensures that these units can withstand high thermal stress while delivering reliable performance over the years.

In summary, Crown Boiler’s AWI061, TWI061, AWI162, AWI128, and AWI295 models offer a range of solutions equipped with advanced technologies and features designed for efficiency and reliability. These boilers are suitable for diverse heating needs, promising optimal comfort and convenience in both residential and commercial settings. With Crown Boiler's longstanding commitment to quality, customers can be assured of a robust heating solution backed by exceptional service.
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