opening of the valve may be held positively without drift or consumption of
a power means. The valve body shall conform to the requirements for valves
specified in paragraph PIPING.
2.5.15.7
Plant Master Controller
Plant master controller for nitrogen pressurized systems shall react in
response to temperature transmitter signals from a temperature sensing
element in the return water header and shall provide the necessary signals
to the HTW generator master controllers. The plant master controller shall
have a manual selector station for selecting either automatic control or
manual control and a means for adjusting the set point return water
temperature control.
2.5.15.8
Clock
The clock shall be electric synchronous motor type, except as modified
herein. The clock shall be for surface mounting and suitable for operation
on 115-volt, 60 Hz single-phase electric service. The clock shall have a
white dial, easy-to-read black numerals, black hands, red sweep second
hand, and external manual reset knob at bottom of case. The motor gear
train shall be sealed in a permanent oil bath. The clock dial shall be 380
mm 15 inch size.
2.5.16
Panel Piping and Wiring
High-pressure and high-temperature values shall be pneumatically or
electrically transmitted, or both, to the panel. Pneumatic signals shall
be 0.69 to 104 kPa 3 to 15 psig. Piping connectors to indicators shall be
6.4 mm 1/4 inch OD copper tubing conforming to ASTM B 68MASTM B 68. Flow
signals shall be transmitted either pneumatically or electrically to the
panel-mounted receiver. Copper tubing connections and electric wiring
shall be run to a terminal block located on the inside of the panel front
near the bottom. Wiring shall be terminated at an identified terminal
strip. Wiring shall be suitable for boiler room requirements and installed
according to NFPA 70.
2.5.17
Pilot Lights
Pilot lights shall be assembled in a factory-built cabinet, suitable for
flush mounting in cutouts in boiler control panel, complete with extruded
trim, clamps, and sheet metal rear housing, and finished in baked black
enamel. Lens shall be white plastic and engraved in black ink. Lettering
shall be 19 mm 3/4 inch high and black. Two lamps per pilot shall be
provided and independently wired. Lamps shall be 6 watts, 24 volts dc, S-6
incandescent type, supplied with color caps, one red and one green per
pilot light. Lens bezels shall be black unless otherwise indicated.
2.5.18
Continuous Emissions Monitoring
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NOTE: A continuous emissions monitoring system
(CEMS) is required by the Clean Air Act Amendment
(CAAA) of 1990 if the fuel utilized is oil or coal
and the heat input is 3 megawatts (1 million BTU/HR)
or greater. A CEMS may also be required by state or
local laws. If a CEMS is necessary the designer
shall review the CAAA and the relevant state or
local law early in the project to allow time to
SECTION 15555A
Page 47
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