Daikin DPSA Manual page 35

2 .07 Safety Options
A. Unit Shall be provided with a safety shutdown
terminal for installation of field emergency input
B. Unit Shall be provided with factory installed supply
air smoke detector
C. Unit shall be provided with factory installed return air
smoke detector
D. Unit shall be provided with factory installed supply
and return air smoke detector
2 .08 Cooling Coil
A. The cooling coil section shall be installed in a draw-
through configuration, upstream of the supply air
fan. The coil section shall be complete with factory
piped cooling coil and sloped drain pan.
B. Direct expansion (DX) cooling coils shall be
fabricated of seamless 1/2" diameter high efficiency
copper tubing that is mechanically expanded into
high efficiency aluminum plate fins. Coils shall be
a multi-row, staggered tube design with a minimum
of 4 rows. All units shall have two independent
refrigerant circuits and shall use an interlaced coil
circuiting that keeps the full coil face active at all
load conditions.
C. Each refrigeration circuit shall be equipped with a
thermostatic expansion valve for control refrigerant
flow control.
D. The cooling coil casing and all coil block offs shall be
constructed with stainless steel to prevent corrosion.
E. The refrigerant suction lines shall be fully insulated
from the expansion valves to the compressors.
F. The distributor tubes shall be sleeved or coated to
provide longevity and protection from leaks.
G. All coils shall be factory leak tested with high
pressure air under water.
H. The drain pan shall be stainless steel and designed
to comply with ASHRAE- 62.1 double sloped
requirements drain pan shall be provided with the
cooling coil. The drain pan shall extend beyond
the leaving side of the coil and underneath the
cooling coil connections. The drain pan shall have
a minimum slope of 1/8" per foot to provide positive
draining. The drain pan shall be connected to a
threaded drain connection extending through the
unit base. Units with stacked cooling coils shall be
provided with a secondary drain pan piped to the
primary drain pan.
I. Insulation under the drain pan should be a closed
cell structure to prevent moisture from wicking under
the drain pan. Fiberglass is not allowed.
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2 .09 Corrosion Protection
A. All Indoor Heating and Cooling coils shall be
provided with a corrosion protection coating rated
for a minimum of 6000 hours of salt spray resistance
per ASTM B 117-90 salt spray performance testing.,
ASTM B 117-90 salt spray performance.
B. All Outdoor condenser coils shall be provided with a
corrosion protection coating rated for a minimum of
6000 hours of salt spray resistance per ASTM B 11-
7-90 salt spray performance testing, ASTM B 117-90
salt spray performance.
C. All Indoor Heating and Cooling coils and the outdoor
condenser coils shall be provided with a corrosion
protection coating rated for a minimum of 6000
hours of salt spray resistance per ASTM B 11-7-90
salt spray performance testing, ASTM B 117-90 salt
spray performance.
2 . 1 0 Modulating Hot Gas and Liquid Reheat
A. Hot gas reheat: Unit shall be equipped with a fully
modulating hot gas reheat coil with hot gas coming
from the unit condenser
1. Hot gas reheat coil shall be a Microchannel
design. The aluminum tube shall be a micro
channel design with high efficiency aluminum
fins. Fins shall be brazed to the tubing for a
direct bond. The capacity of the reheat coil shall
allow for a 20°F temperature rise at all operating
conditions.
2. The modulating hot gas reheat systems shall
allow for independent control of the cooling
coil leaving air temperature and the reheat coil
leaving air temperature. The cooling coil and
reheat coil leaving air temperature set points
shall be adjustable through the unit controller.
During the dehumidification cycle the unit shall
be capable of 100% of the cooling capacity.
The hot gas reheat coil shall provide discharge
temperature control within +/- 2°F.
3. Each coil shall be factory leak tested with high-
pressure air under water.
B. Liquid sub-cool reheat: Unit shall be equipped with
a fully modulating liquid sub-cool reheat coil using
hot liquid coming leaving the unit condenser to
reheat saturated leaving evaporator air to neutral air
temperatures leaving the unit.
1. Liquid sub-cool reheat coil shall be a
Microchannel design. The aluminum tube shall
be a micro channel design with high efficiency
aluminum fins. Fins shall be brazed to the tubing
for a direct bond.
2. The modulating liquid sub-cool reheat system
shall be utilized for independent control of the
cooling coil leaving air temperature and the
leaving/supply air temperature.
35
General Specification
CAT 258 • REBEL APPLIED ROOFTOP