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GUIDE SPECIFICATIONS — 581A210-300 UNITS (cont)
3. Optional pre-coated aluminum-fin coils shall have a
durable epoxy-phenolic coating to provide protection
in mildly corrosive coastal environments. Coating
shall be applied to the aluminum fin stock prior to the
fin stamping process to create an inert barrier
between the aluminum fin and copper tube. Epoxy-
phenolic barrier shall minimize galvanic action
between dissimilar metals.
4. Copper-fin coils shall be constructed of copper fins
mechanically bonded to copper tubes and copper
tube sheets. Galvanized steel tube sheets shall not
be acceptable. A polymer strip shall prevent coil
assembly from contacting the sheet metal coil pan to
minimize potential for galvanic corrosion between
coil and pan. All copper construction shall provide
protection in moderate coastal environments.
5. E-Coated aluminum-fin coils shall have a flexible
epoxy polymer coating uniformly applied to all coil
surface areas without material bridging between fins.
Coating process shall ensure complete coil encapsu-
lation. Color shall be high gloss black with gloss —
60 deg of 65 to 90% per ASTM D523-89. Uniform dry
film thickness from 0.8 to 1.2 mil on all surface areas
including fin edges. Superior hardness characteris-
tics of 2H per ASTM D3363-92A and cross-hatch
adhesion of 4B-5B per ASTM D3359-93. Impact
resistance shall be up to 160 in./lb (ASTM D2794-
93). Humidity and water immersion resistance shall
be up to minimum 1000 and 250 hours respectively
(ASTM D2247-92 and ASTM D870-92). Corrosion
durability shall be confirmed through testing to be no
less than 1000 hours salt spray per ASTM B117-90.
Coil construction shall be aluminum fins mechani-
cally bonded to copper tubes.
6. E-Coated copper-fin coils shall have a flexible epoxy
polymer coating uniformly applied to all coil surface
areas without material bridging between fins. Coating
process shall ensure complete coil encapsulation.
Color shall be high gloss black with gloss — 60 deg
of 65 to 90% per ASTM D523-89. Uniform dry film
thickness from 0.8 to 1.2 mil on all surface areas
including fin edges. Superior hardness characteris-
tics of 2H per ASTM D3363-92A and cross-hatch
adhesion of 4B-5B per ASTM D3359-93. Impact
resistance shall be up to 160 in./lb (ASTM D2794-
93). Humidity and water immersion resistance shall
be up to minimum 1000 and 250 hours respectively
(ASTM D2247-92 and ASTM D870-92). Corrosion
durability shall be confirmed through testing to be no
less than 1000 hours salt spray per ASTM B117-90.
Coil construction shall be copper fins mechanically
bonded to copper tubes with copper tube sheets.
Galvanized steel tube sheets shall not be accept-
able. A polymer strip shall prevent coil assembly
from contacting sheet metal coil pan to maintain
coating integrity and minimize corrosion potential
between coil and pan.
F. Heating Section:
1. Induced-draft combustion type with energy saving
direct-spark ignition system and redundant main gas
valve with 2-stage capability.
2. The heat exchanger shall be of the tubular-section
type constructed of a minimum of 20-gage steel
coated with a nominal 1.2 mil aluminum-silicone alloy
for corrosion resistance.
3. Burners shall be of the in-shot type constructed of
aluminum-coated steel.
4. All gas piping shall enter the unit at a single location.
5. Stainless steel heat exchanger (minimum 20 Ga type
409 stainless steel) shall be available.
G. Refrigerant Components:
Each refrigerant circuit shall include:
1. Thermostatic expansion valve (TXV) with removable
power element.
2. Filter driers.
3. Gage port and connections on suction and
discharge.
H. Filter Section:
Standard filter section shall consist of factory-installed
2-in. thick throwaway fiberglass filters.
I. Controls and Safeties:
1. Electro-Mechanical Control:
a. Economizer control (optional).
b. Capacity control (2-step).
c. Unit shall be complete with self-contained low-
voltage control circuit.
2. Safeties:
a. Unit shall incorporate a solid-state compressor
lockout which provides optional reset capability at
the space thermostat, should any of the following
safety devices trip and shut off compressor:
1) Compressor lockout protection provided for
either internal or external overload.
2) Low-pressure protection.
3) Freeze protection (evaporator coil).
4) High-pressure protection (high pressure switch
or internal).
b. Induced draft heating section shall be provided
with the following minimum protections:
1) High-temperature limit switch.
2) Induced-draft motor speed sensor.
3) Flame rollout switch.
4) Flame proving controls.
5) Redundant gas valve.
J. Operating Characteristics:
1. Unit shall be capable of starting and running at 125 F
ambient outdoor temperature per maximum load
criteria of ARI Standard 360.
2. Unit with standard controls will operate in cooling
down to an outdoor ambient temperature of 40 F.
3. Size 18 and 20 ton units shall have 3 fully indepen-
dent refrigerant circuits to allow for 33% capacity per
circuit.
K. Electrical Requirements:
All unit power wiring shall enter unit cabinet at a single
location.
L. Motors:
1. Compressor motors shall be cooled by refrigerant
gas passing through motor windings and shall have
line break thermal and current overload protection.
2. All fan motors shall have permanently lubricated,
sealed bearings and inherent automatic-reset ther-
mal overload protection or manual reset calibrated
circuit breakers.
3. All indoor-fan motors 5 hp and larger shall meet the
minimum efficiency requirements as established by
the Energy Policy Act of 1992 (EPACT), effective
October 24, 1997.