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F. Controls and Safeties:
Operating controls and safeties shall be factory
selected, assembled, and tested. Minimum control
functions shall be as listed below:
1. Controls:
a. Time-delay restart control to prevent com-
pressor short-cycling.
b. Defrost control to consist of a time and tem-
perature activated system that initiates
defrost mode at selectable intervals of 30,
50, or 90 minutes in response to a tempera-
ture signal.
2. Safeties:
a. High discharge pressure cutout switch.
b. Loss-of-charge cutout switch.
c. Compressor motor current and temperature
overload cutouts.
d. Five-minute recycle protection to prevent
compressor short cycling.
e. Device to hold the compressor off-line until
manual reset at the thermostat when any of
the following are tripped: High discharge
pressure, high compressor motor tempera-
ture, or loss of charge.
G. Electrical Requirements:
1. Factory supplied and installed transformer shall
provide 24 v control voltage.
2. All power and control circuit wiring shall com-
ply with local and national codes.
H. Special Features:
1. Head Pressure Control:
Control shall vary the fan motor speed in
response to the saturated condensing tempera-
ture of the unit. The control shall be capable
of maintaining a condensing temperature of
100 F ± 10 F with outdoor temperature at
–20 F.
2. Outdoor Thermostat:
Adjustable control shall activate electric heaters
in stages to provide supplemental heat. Range:
–30 F to 90 F.
3. Gage Panel:
Panel shall provide one suction pressure and
one discharge pressure gage mounted on a
common panel. A shut-off valve shall be pro-
vided for each gage.
4. Coil Guard:
Grille shall protect condenser coil from damage
by large objects or vandalism.
5. Hail Guard:
Guard shall protect unit against damage from
damage by hail or flying debris.
6. Optional Condenser Coil Materials:
a. 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 cop-
per tube. Epoxy-phenolic barrier shall mini-
mize galvanic action between dissimilar
metals.
b. Copper-Fin Coils:
Shall be constructed of copper fins mechani-
cally 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 sheet
metal coil pan to minimize potential for gal-
vanic corrosion between the coil and pan.
All copper construction shall provide protec-
tion in moderate coastal applications.
c. Post-Coated Aluminum-Fin Coils:
Shall have a durable organic coating uni-
formly applied over all coil surfaces. Coating
shall be deep brown color applied by a dip
and bake process to ensure complete encap-
sulation of all coil surfaces. Coated coil shall
withstand 1,000-hour salt spray test in
accordance with ASTM B117. Coil con-
struction shall be aluminum fins mechani-
cally bonded to copper tubes.
d. Post-Coated Copper-Fin Coils:
Shall have a durable organic coating uni-
formly applied over all coil surfaces. Coating
shall be deep brown color applied by a dip
and bake process to ensure complete encap-
sulation of all coil surfaces. Coated coil shall
withstand 1,000 hour-salt spray test in
accordance with ASTM B117. Coil con-
struction shall be copper fins mechanically
bonded to copper tubes.
7. Thermostat Controls:
a. Programmable multi-stage thermostat with
7-day clock, holiday scheduling, large backlit
display, remote sensor capability, and
Title 24 compliance.
b. TEMP System programmable communi-
cating multi-stage thermostat with fan
switch, timeclock, LCD display, °F/°C capa-
bility, and CCN (Carrier Comfort Network)
compatibility.
c. Commercial Electronic Thermostat with
7-day timeclock, auto-changeover, multi-
stage capability, and large LCD temperature
display.
d. Non-programmable thermostat with fan
switch subbase.
Guide specifications —
38AQS008 outdoor unit (cont)