an allowable water velocity not less than 0.9 m/s 3 fps nor more than 3 m/s
10 fps with a fouling factor of [0.0005] [0.001]. The design pressure drop
shall govern the number of passes. Control valve on the water supply line
shall be [the automatic, self-contained type, controlled by condensing
pressure which close bubble-tight when compressor is not operating.] [the
modulating three-way type, controlled by pressure controller.]
2.8
Each unit shall be the counter-flow blow-through design, with single-side
air entry. The unit shall have fan assemblies built into the unit base,
with all moving parts factory mounted and aligned. Primary construction of
the pan section, the cabinet, etc. shall be not lighter than 1.6 mm (16
gauge) 16 gauge steel, protected against corrosion by a zinc coating. The
zinc coating shall conform to ASTM A 153/A 153M and ASTM A 123/A 123M, as
applicable and have an extra heavy coating of not less than 0.76 kg/square
meter 2-1/2 ounces per square foot of surface. Cut edges shall be given a
protective coating of zinc-rich compound. After assembly, the
manufacturer's standard zinc chromatized aluminum or epoxy paint finish
shall be applied to the exterior of the unit. Unit shall be rated in
accordance with ARI 490 and tested in accordance with ASHRAE 64.
2.8.1
Pan Section
The pan shall be watertight and shall be provided with drain, overflow, and
make-up water connections. Standard pan accessories shall include access
doors, a lift-out strainer of anti-vortexing design and a brass make-up
valve with float ball.
2.8.2
Fan Section
Fan shall be the [centrifugal] [propeller] type in accordance with
paragraph Fans. Fan and fan motor shall not be located in the discharge
airstream of the unit. Motors shall have [open] [dripproof] [totally
enclosed] [explosion proof] enclosure and shall be suitable for the
indicated service. The condensing unit design shall prevent water from
entering into the fan section.
2.8.3
Condensing Coil
**************************************************************************
NOTE: Delete the copper or aluminum tubes and the 3
mil coating except in corrosive environments.
**************************************************************************
Coils shall have [nonferrous] [copper or aluminum] tubes of 10 mm 3/8 inch
minimum diameter without fins. Coils shall be protected with a minimum
0.075 mm 3 mil thick [phenolic] [or] [vinyl] coating. Casing shall be
galvanized steel or aluminum. Contact of dissimilar metals shall be
avoided. Coils shall be tested in accordance with ASHRAE 15 at the factory
and be suitable for the working pressure of the installed system. Each
coil shall be dehydrated and sealed after testing and prior to evaluation
and charging. Each unit shall be provided with a factory operating charge
of refrigerant and oil or a holding charge. Unit shipped with a holding
charge shall be field charged.
2.8.4
Water Distribution System
Water shall be distributed uniformly over the condensing coil to ensure
SECTION 15652A
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