provided, arranged to receive a signal from the boiler plant
master controller and water regulating valve assembly. Quantity
of deaerator feedwater pumps shall match quantity of boilers.
Panel mounted Lead-Lag-Off-Continuous switch for each feedwater
pump shall be provided.
3.
Sequence of Operation: From cold start of plant, when plant
master controller indicates one boiler to start, lead pump shall
start. When second boiler is indicated to start, lag pump shall
start and this process shall continue for additional boiler
starts. Feedwater pumps shall run continuously. When one boiler
shuts down, one feedwater pump shall shut down. When all boilers
are off, all pumps shall be off. Should there be a failure of any
pump, the next pump in sequence shall operate automatically.
Audible and visual high and low water level alarms shall be
provided by bell or horn with silence switch and individual red
oil tight lights. A low-low water level signal shall cut off
feedwater pumps. Deaerator water level control system shall
provide a 4-20 mA dc signal to the condensate receiver control
panel to start transfer pumps.
2.8
CONDENSATE RETURN SYSTEM
**************************************************************************
NOTE: Coordinate the components of this system with
the deaerator selection. Some components are
specified with the two tank-type deaerator.
**************************************************************************
Condensate return system shall be factory assembled package system
including condensate surge tank, transfer pumps, controls, auxiliary
equipment and piping as shown.
2.8.1
Condensate Surge Tank
The condensate surge tank shall be [_____] mm inch diameter by [_____] mm
inch long with 280 by 380 mm 11 by 15 inch elliptical manhole. Condensate
surge tank shall have [_____] minutes of storage and capacity of [_____]
liters gallons flooded. Condensate surge tank, base, piping nozzle
construction shall be as specified. The condensate surge tank shall
include the following:
a.
Required tappings and manway.
b.
Thermometer.
c.
Gauge glass.
d.
Water level controller with make-up valve.
e.
Three-valve bypass and strainer for control devices.
f.
Suction shutoff valve.
g.
Suction strainer.
h.
Suction flexible fitting.
i.
Pump discharge check valve.
SECTION 15561A
Page 80
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