2.8.5.3
Control Panel
The control panel shall provide signals to the diverter valve at a preset
time interval to reverse water flow to drive the tube brushes down the
tubes and then signal the valve to reverse the water flow to drive the
brushes back down the tubes to their original position. The controller
shall have the following features as a minimum:
a.
Timer to initiate the on-load cleaning cycle.
b.
Manual override of preset cleaning cycle.
c.
Power-on indicator.
d.
Diverter-position indicator.
e.
Cleaning-cycle-time adjustment
f.
Flow-switch bypass.
2.8.6
Gaskets
Gaskets shall conform to ASTM F 104 - classification for compressed sheet
with nitrile binder and acrylic fibers for maximum 371 degrees C 700
degrees F service.
2.8.7
Bolts and Nuts
Bolts and nuts, except as required for piping applications, shall be in
accordance with ASTM A 307. The bolt head shall be marked to identify the
manufacturer and the standard with which the bolt complies in accordance
with ASTM A 307.
2.9
FABRICATION
2.9.1
Factory Coating
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NOTE: For equipment to be installed outdoors,
adequate protection will be specified.
Manufacturers must submit evidence that unit
specimen have passed the specified salt spray fog
test. A 125 hour test will be specified in a
noncorrosive environment and a 500 hour test will be
specified in a corrosive environment.
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Unless otherwise specified, equipment and component items, when fabricated
from ferrous metal, shall be factory finished with the manufacturer's
standard finish, except that items located outside of buildings shall have
weather resistant finishes that will withstand [125] [500] hours exposure
to the salt spray test specified in ASTM B 117 using a 5 percent sodium
chloride solution. Immediately after completion of the test, the specimen
shall show no signs of blistering, wrinkling, cracking, or loss of adhesion
and no sign of rust creepage beyond 3 mm 1/8 inch on either side of the
scratch mark. Cut edges of galvanized surfaces where hot-dip galvanized
sheet steel is used shall be coated with a zinc-rich coating conforming to
ASTM D 520, Type I.
SECTION 15620A
Page 45
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