Daikin DPSA Manual page 37

2 . 1 4 Electric Heat
A. The rooftop unit shall include an electrical resistance
heating coil section. Heating coils shall be
constructed of a low watt density, nickel-chromium
alloy resistance wire with intermediate supports that
include ceramic bushings. The electrical contractors
shall be of the full line-breaking type with all the
electrical power legs being disconnected when the
contactors are not energized. All electrical circuit
wiring shall be designed with copper conductors,
aluminum wires are not acceptable. Heating element
branch circuits shall be individually fused to a
maximum of 48 Amps per NEC requirements. The
power supply for the electric heater shall be factory
wired into the units main power block or disconnect
switch.
B. The heating modules shall have an automatic
reset, high temperature limit safety protection.
A secondary high limit protection shall also be
provided that requires a manual reset. An airflow
switch shall be provided with the heating module
to prevent the electric heater from operating in the
event of no airflow.
C. The electric heat elements shall be controlled by
the factory installed DDC unit control system. The
heater shall have proportional SCR control. The
unit controller shall modulate the electric heater to
maintain the discharge air temperature set point.
2 . 1 5 Gas Heat
A. The gas furnace design shall be factory installed
downstream of the supply air fan in the heat section.
B. The heat exchanger shall include a 439 grade
stainless steel. Aluminized steel heat exchangers
are not acceptable. The heat exchanger design shall
collect condensate in a collection point and have a
condensate drain.
C. The furnace will be supplied with a staged induced
draft burner. The burner shall be capable of 2 stages
of control and will operate at either 50% or 100% of
rated capacity.
D. The furnace will be supplied with a staged induced
draft burner. The burner shall be capable of 4 stages
of control and will operate at either 25, 50, 75 or
100% of rated capacity.
E. The furnace will be supplied with a modulating
induced draft burner. The burner shall be controlled
for low fire start. The burner shall be capable of
continuous modulation between 20% and 100% (5:1
control) of rated capacity.
F. The furnace will be supplied with a modulating
induced draft burner. The burner shall be controlled
for low fire start. The burner shall be capable of
continuous modulation between 10% and 100%
(10:1 control) of rated capacity.
G. The furnace will be supplied with a modulating
induced draft burner. The burner shall be controlled
for low fire start. The burner shall be capable of
continuous modulation between 5% and 100% (20:1
control) of rated capacity.
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H. The burner shall be specifically designed to burn
natural gas and shall include a micro-processor
based flame safeguard control, combustion air
proving switch, pre-purge timer and spark ignition.
Status and alarm codes are available at the unit
controller via a network connection and are available
for BAS integration.
I. Provide with a 10 year gas heat exchanger warranty
J. Provide with a 20 year gas heat exchanger warranty
2 . 1 6 Draw-through Filters
A. All units shall be provided with clogged filter
switches and alarm enunciation
B. All units shall be provided with electronic pressure
transducer filter measuring controls integrated with
the BAS and alarm enunciation
C. All units shall be provided with a through the wall
magnehelic filter gauge that displays filter loading.
D. Unit shall be provided with a draw-through filter
section.
E. The filter rack shall be designed to accept a 2"
pleated filter. The manufacturer shall ship the rooftop
unit with 2" MERV 8 filters. The contractor shall
furnish and install, at building occupancy, the final
set of filters per the contract documents.
F. The filter rack shall be designed to accept a 2"
pleated Merv 8 pre-filter and a 4" post filter. The
manufacturer shall ship the rooftop unit with 2"
MERV 8 filter. The contractor shall furnish and
install, at building occupancy, the final set of filters
per the contract documents.
G. The filter rack shall be designed to accept a 2"
pleated pre-filter and a 1" header for a up to a 12"
cartridge filter. The manufacturer shall ship the
rooftop unit with 2" MERV 8 pre-filters and a 12"
MERV 14 cartridge filter.
H. The filter rack shall be designed to accept a 2"
pleated pre-filter and a 1" header for a up to a 12"
cartridge filter. The manufacturer shall ship the
rooftop unit with 2" MERV 8 pre-filters and a 12"
MERV 16 cartridge filter.
I. The filter rack shall be designed to accept a 2"
pleated pre-filter and a 1" header for a up to a
12" cartridge filter. The manufacturer shall ship
the rooftop unit with 2" MERV 8 pre-filters and a
12" Carbon Impregnatuded cartridge filter. The
contractor shall furnish and install, at building
occupancy, the final set of filters per the contract
documents.
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General Specification
CAT 258 • REBEL APPLIED ROOFTOP