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a.
Pilot burner shall be natural gas-electric type with the capacity
required to reliably light off the boiler. A 6,000 volt secondary
side ignition transformer shall be supplied and mounted backside
of the windbox.
b.
Pilot shall be liquefied petroleum gas (LPG) type. Two 18 kg 40
lb. cylinders shall be located on concrete pads outside of the
building as shown. Manifold and valves for cylinders to allow
removal and filling of one tank without interrupting service to
pilot shall be included. Regulators and gauges shall have
adequate capacity to serve pilot.
c.
Pilot shall be straight mechanical or atomizing type as specified
for the burner. Pilot system shall be designed to fire No. 2 oil
and shall be provided complete with fuel oil pump, safety shut-off
valve, integral metallic screen strainers and a cartridge type
filter. Ignition transformer shall be rated at not less than
10,000 volts on the secondary side.
d.
Provision shall be made in the burner housing for inspection of
the pilot flame.
e.
Pilot shall be provided with individual manual shut-off valve,
pressure gauge, pressure regulation separate from the main burner,
self closing solenoid valve and vent valve in accordance with FM
P7825a, FM P7825b and UL 795. Pilot and valving shall be in
accordance with NFPA 8501.
2.4.2
Burner Refractory Throat
Burner refractory throat shall be made of high quality castable refractory
suitable for 1650 degrees C 3000 degrees F. The precast refractory in a
steel retaining ring with stainless steel anchors shall be shipped
separately for field mounting on the boiler. Burner refractory throat
shall be concentric with the burner, contoured to ensure complete mixing of
[air and natural gas] [air and oil] [air and natural gas and air and oil],
and designed to assist in complete combustion by radiating heat to the
fuel. Burner shall be so positioned that the flame parallels the contour
of the burner refractory throat but avoids striking the refractory.
2.4.3
Windbox
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NOTE: Intent is to provide capability for flue gas
recirculation (FGR) on all boilers specified, either
for present use or future installation.
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Windbox shall provide even airflow. Windbox shall not interfere with
boiler smoke box door operation and shall have a flange bottom for easy
firm mounting on a support structure. Windbox shall be provided with an
induced flue gas recirculation (FGR) inlet adaptor assembly.
2.4.4
Combustion Air Fan
Combustion air fan shall be centrifugal type with backwardly inclined air
foil bladed wheel. Combustion air-fan wheel shall be directly driven by a
SECTION 15561A
Page 35
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