Aerco AM Series Manuale di applicazione - Pagina 3
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1. GENERAL INTRODUCTION
The AERCO AM Series gas fired boilers and water heaters are modulating input boilers that require
an adequate volume and pressure of natural or propane gas for proper operation. The gas
requirements specified herein must be satisfied to ensure efficient combustion. Designers and
installers must adhere to the specifications of AERCO and of the local authorities having jurisdiction.
A thorough understanding and knowledge of these guidelines is required for the successful design
and installation of AM Series boilers and water heaters.
2. GAS TRAIN COMPONENTS
The AM Series unit is a stainless steel modular boiler consisting of individual combustion chambers,
each having its own gas train (gas valve, pre-combustion chamber, and burner), blower, check valve,
igniter, and flame detector, but connected to a common flue. Each group of these components is
referred to as a module. The gas train components have been designed to operate at high combustion
and seasonal efficiencies by closely controlling both the volume and air/fuel mixture to the burner.
Below are descriptions of each of the gas train components for each module.
•
GAS VALVE – An electronic, modulating gas valve with 100% tight shutoff. It controls the
amount of gas delivered to the burner.
•
MODULATING PRE-MIX BLOWER – A variable speed blower mounted to the combustion
chamber, where combustion air and gas mix prior to entering the burner, providing controlled
combustion. The outlet of the blower leads to a check valve, which prevents any backflow of
combustion gases.
•
LOW NOx BURNER – A metal fiber mesh covers a stainless steel burner head on which
combustion occurs. The burner operation is stable throughout the entire input range of the
boiler.
3. GAS PRESSURE REQUIREMENTS
The AERCO AM Series of boilers and water heaters require a stable gas input pressure. The inlet
supply to the unit must be at least 3 " W.C. when firing at maximum input. Maximum allowable gas
pressure is 13" W.C. Static gas pressure (when the unit is not firing) may vary, however actual gas
pressure should be measured when the unit is in operation (firing). Measure the gas pressure with a
manometer at the port provided in the gas valve. In a multiple boiler installation, gas pressure should
initially be set for a single boiler in operation and then remaining boilers should be staged on at full
fire to ensure that gas pressures never fall below the minimum allowable pressure of 3" W.C.
An external gas pressure regulator is mandatory for the State of Massachusetts, regardless of supply
pressure; for all other jurisdictions, a lock-up style regulator is required when supply pressure is
greater than 13" W.C. (see Fig. 1). The regulator must be installed with at least 2 feet of pipe
between the regulator and the unit gas inlet. The regulator discharge range must able to maintain 3"
W.C. Gas regulators are self-contained with tapped diaphragm vent ports allowing the diaphragm to
change its position. These vents typically require piping to the outside.
Every AM unit requires a manual shutoff valve. CSA requires that no other components can be installed
between the boiler and this shutoff valve except for pipe fittings such as a pipe union. If an external
regulator is used, an additional isolation/service valve must be installed upstream of the regulator (see
Figure 1). Gas piping should contain ground unions for removal of the gas piping to the unit for
maintenance or service as required. Gas piping should never obstruct removal of the unit side panels
and should not be supported from the unit itself. Gas piping should be supported properly from the floor
or overhead as the installation allows.
PR1 04/08/2014
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, New York 10913 • Phone: 800-526-0288
GF-2060
TAG-0073_0B
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