General Controls

to support the total weight of ash when the silo is full, and compressed

air piping. Each diffuser module shall be mounted on the silo floor using

sloped concrete pads. System shall operate from the plant air system.

Provide pressure reducing valves, safety valves, and controls for a

complete system.

]2.12.21

General Controls

Provide a centrally controlled operation, with auxiliary local operation,

and a monitoring control system with graphic display for the ash conveying

system. Provide local control stop-start push buttons and indication

stations for chain drag conveyor, screw conveyors, bucket elevator, and

rotary ash conditioner. Ash handling system manufacturer shall provide

measuring devices, status switches, solenoid valves, and auxiliary parts

necessary to safely control and operate the system. Provide related

electrical work required to operate the ash handling system. [Ash handling

system manufacturer shall provide detailed control logic diagrams to the

digital process control and data acquisition system manufacturer specified

under VAMS Section 15901N CONTROLS AND INSTRUMENTATION BOILER PLANT.]

2.12.21.1

Functions

Provide capability to perform any of the following functions from the

operator interface console specified under VAMS Section 15901N CONTROLS NAD

INSTRUMENTATION BOILER PLANT.

a.

System Start

b.

System Stop

c.

Auto/Manual/Index Mode of Operation Selection

d.

Selection of Bypass of any Boiler

e.

Manual Index to any Intake

f.

Selection of Ash Silo for Baghouse Ash

2.12.21.2

Status Indicators

Provide sensors or contact closures for status indication on the operator

interface console specified under VAMS Section 15901N CONTROL SNAD

INSTRUMENTATION BOILER PLANT[, or on the annunciator over the central

control panel] for the following:

a.

Conveyor On

b.

Unit On (one required for each unit)

c.

Final Line Purge On/Complete

d.

Baghouse Ash to Ash Silo

2.12.21.3

Alarms

Provide sensors such that the following items can be alarmed on the

operator interface console specified under VAMS Section 15901N CONTROLS

AND INSTRUMENTAITON BOILER PLANT[ or on the annunciator over the central

control panel]:

SECTION 15502N

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