139
3. Optional copper-fin evaporator and condenser coils
(3 phase models only):
a. Shall be constructed of copper fins mechani-
cally bonded to copper tubes and copper tube
sheets.
b. Galvanized steel tube sheets shall not be
acceptable.
c. A polymer strip shall prevent coil assembly from
contacting the sheet metal coil pan to minimize
potential for galvanic corrosion between coil and
pan.
4. Optional e-coated aluminum-fin evaporator and
condenser coils (3 phase models only):
a. Shall have a flexible epoxy polymer coating
uniformly applied to all coil surface areas with-
out material bridging between fins.
b. Coating process shall ensure complete coil
encapsulation of tubes, fins and headers.
c. Color shall be high gloss black with gloss per
ASTM D523-89.
d. Uniform dry film thickness from 0.8 to 1.2 mil
on all surface areas including fin edges.
e. Superior hardness characteristics of 2H per
ASTM D3363-92A and cross-hatch adhesion of
4B-5B per ASTM D3359-93.
f. Impact resistance shall be up to 160 in.-lb
(ASTM D2794-93).
g. Humidity and water immersion resistance shall
be up to minimum 1000 and 250 hours respec-
tively (ASTM D2247-92 and ASTM D870-92).
h. Corrosion durability shall be confirmed through
testing to be no less than 1000 hours salt spray
per ASTM B117-90.
J. (23 81 19.13.J.) Refrigerant Components:
1. Refrigerant circuit shall include the following con-
trol, safety, and maintenance features:
a. Fixed orifice metering system on 04-06 models
and TXV on 07 size models shall include a mul-
tiple feed distribution system that optimizes coil
performance.
b. Refrigerant filter drier - Solid core design.
c. Service gage connections on suction and dis-
charge lines.
d. Pressure gage access through a specially
designed access port in the top panel of the unit.
2. There shall be gage line access port in the skin of
the rooftop, covered by a black, removable plug.
a. The plug shall be easy to remove and replace.
b. When the plug is removed, the gage access port
shall enable maintenance personnel to route
their pressure gage lines.
c. This gage access port shall facilitate correct and
accurate condenser pressure readings by
enabling the reading with the compressor access
panel on.
d. The plug shall be made of a leak proof,
UV-resistant, composite material.
3. Compressors:
a. Unit shall use fully hermetic, scroll compressor
for each independent refrigeration circuit.
b. Compressor motors shall be cooled by refriger-
ant gas passing through motor windings.
c. Compressors shall be internally protected from
high discharge temperature conditions.
d. Compressors shall be protected from an over-
temperature and over-amperage conditions by
an internal, motor overload device.
e. Compressor shall be factory mounted on rubber
grommets.
f. Compressor motors shall have internal line
break thermal, current overload and high pres-
sure differential protection.
g. Crankcase heaters shall not be required for nor-
mal operating range, unless required by compres-
sor manufacturer due to refrigerant charge limits.
h. Compressor on 04-06 models shall be of a sin-
gle stage cooling capacity design and 07 models
shall be a two stage cooling capacity design.
K. (23 81 19.13.K.) Filter Section:
1. Filters access is specified in the unit cabinet section
of this specification.
2. Filters shall be held in place by a pivoting filter
tray, facilitating easy removal and installation.
3. Shall consist of factory installed, low velocity,
throw-away 2-in. thick fiberglass filters.
4. Filters shall be standard, commercially available
sizes.
5. Only one size filter per unit is allowed.
L. (23 81 19.13.L.) Evaporator Fan and Motor with
Axion™ Fan Technology:
1. Direct drive evaporator fan motor:
a. Shall be a ECM motor design.
b. Shall have permanently lubricated bearings.
c. Shall have inherent automatic-reset thermal
overload protection.
d. Shall have slow ramp up to speed capabilities.
e. Shall require no fan/motor belts for operation,
adjustments and or initial fan speed set up.
f. Fan DC voltage set up on Unit Control Board
can eliminate the need of removal of blower
access door, required on conventional belt drive
systems.
g. Shall be internally protected from electrical
phase reversal and loss.
2. Evaporator fan:
a. Shall be easily set with dedicated selection
switch and adjustment pot on unit control
board.
Guide specifications (cont)
To Next Page
Loading...
Need help?
General
