Filter
Top Products
51
3. Optional Copper--fin coils:
a. Shall be constructed of copper fins mechanically 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 coils shall have a flexible epoxy polymer coating uniformly applied to a ll
coil surface areas without material bridging between fins.
a. Coating process shall ensure complete coil encapsulation of tubes, fins and headers.
b. Color shall be high gloss black with gloss per ASTM D523--89.
c. Uniform dry film thickness from 0.8 to 1.2 mil on all surface areas including fin edges
d. Superior hardness characteristics of 2H per ASTM D3363--92A and cross--hatch adhesion of 4B--5B per
ASTM D3359--93.
e. Impact resistance shall be up to 160 in.--lb (ASTM D2794--93).
f. Humidity and water immersion resistance shall be up to minimum 1000 and 250 hours respectively (ASTM
D2247--92 and ASTM D870--92).
g. Corrosion durability shall be confirmed through testing to be no less than 1000 hours salt spray per ASTM
B117--90.
5. Optional E--coate d copper--fin coils
a. Shall have a flexible epoxy polymer coating uniformly applied to all coil surface areas without material
bridging between fins.
b. Galvanized steel tube sheets shall not be acceptable.
c. A polymer strip shall prevent coil assembly from contacting sheet metal coil pan to maintain coating integ-
rity and minimize corrosion potential between coil and pan.
d. Coating process shall ensure complete coil encapsulation of tubes, fins and headers.
e. Color shall be high gloss black with gloss per ASTM D523--89.
f. Uniform dry film thickness from 0.8 to 1.2 mil on all surface a reas including fi n edges
g. Superior hardness characteristics of 2H per ASTM D3363--92A and cross--hatch adhesion of 4B--5B per
ASTM D3359--93.
h. Impact resistance shall be up to 160 in.--lb (ASTM D2794--93).
i. Humidity and water immersion resistance shall be up to minimum 1000 and 250 hours respectively (ASTM
D2247--92 and ASTM D870--92).
j. Corrosion durability shall be confirmed through testing to be no less than 1000 hours salt spray per ASTM
B117--90.
23 81 19.13.K. Refrigerant Components
1. Refrigerant circuit shall inc lude the following control, safety, and maintenance features:
a. Fixed orifice metering system shall prevent m al--distribution of two--phase refrigerant by including mul-
tiple fixed orifice devices in each refrigeration circuit. Each orifice is to be optimized to the coil circuit it
serves.
b. Refrigerant filter drier.
c. Service gauge connections on suction and discharge line s.
d. Pressure gauge access through a specially designed access port in the top panel of the unit.
2. There shall be gauge 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 gauge access port shall enable maintenance personnel to route their pressure
gauge lines.
c. This gauge access port shall facilitate correct and accurate condenser pressure readings by enabling the
reading with the compressor access panel on.
d. The pl ug shall be made of a lea k proof, UV--resistant, composite material.
3. Compressors
a. Unit shall use one fully hermetic, scroll compressor for each independent refrigeration circuit.
b. Compressor motors shall be cooled by refrigerant ga s passing through motor windings.
c. Compressors shall be internally protected from high discharge temperature conditions using a Thermal
Overload Disk (TOD) install ed at the muffler plate on 04--06 sizes and at the fixed scroll discharge gas
outlet on 07.
558J