2.1.3
Cast Iron Boiler
Boiler shall be of the rectangular, sectional type, self-contained,
packaged type, complete with accessories, mounted on a structural steel
base. Cast iron sections shall be free of leaks under all operating
conditions. Access shall be provided to permit cleaning of internal tube
surfaces.
2.1.4
Condensing Boiler
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NOTE: Due to the sulfur content of fuel oil,
condensing boilers should only be considered if
natural gas is used.
The lower the return temperature of water entering
the boiler the higher the resulting boiler
efficiency. (See ASHRAE HVAC Equipment and
Applications Handbook). The return water
temperature should be at or below the dew point of
the flue gas to result in the formation of
condensate. This condition may not occur within a
steam heating system. Therefore, condensing boilers
should only be used for hot water service. In
addition, the water distribution system and heating
coils should be designed for higher temperature
differentials.
Condensing boilers may be in the form of fire tube
boilers with pulse combustion, copper fire tube
boilers, or multiple heat exchanger boilers. The
military specifications listed in the preceding
paragraphs concerning fire tube and water tube
boilers do not apply to condensing boilers.
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Each boiler shall be a self-contained packaged type, complete with
accessories, mounted on a structural steel base or a steel base which is
integral to the boiler shell. Each boiler shall conform to the commercial
design used by the manufacturer and shall permit free thermal expansion
without placing undue stress on any part of the boiler. Each boiler which
experiences the formation of condensate within the flue gas shall be
specifically designed for condensing application. Each boiler shall
withstand the corrosive effects of condensate for each part which may be in
contact with the condensate at all possible operating conditions. Each
boiler shall be provided with a separate air intake, exhaust, and
condensate drain. Each boiler shall be designed to withstand the water
temperature differentials anticipated at the required operating conditions
without experiencing any damage due to thermal shock.
2.1.5
Modular Configuration
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NOTE: A modular configuration is a series of small
smaller boilers are manifolded together to provide
heating for larger loads. This arrangement may be
economical when heating load variances are expected.
Delete this paragraph if a modular configuration is
SECTION 15569A
Page 18
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