(1) -- Loss--of--charge/Low--pressure switch.
(2) -- High--pressure switch.
If any of the above safety devices trip, an LED (light emitting
diode) indicator shall illuminate.
C. Unit shall incorporate “AUTO RESET” compressor
over--temperature, over--current protection.
D. Unit shall operate with conventional thermostat designs
and have a low voltage terminal strip for easy hook--up.
E. Unit shall have freeze--protection thermostat on evapo-
rator coil.
F. Unit shall incorporate an ambient compensated, time
and temperature defrost control.
(1) -- Defrost shall be initiated on the basis of time and liq-
uid line temperature.
(2) -- A 50/80/110--minute timer shall activate defrost cycle
only if liquid line temperature is low enough to indicate a
heavy frost condition.
(3) -- Defrost cycle shall terminate when liquid line sensor
is satisfied and shall have a positive termination time of 10
minutes.
ELECTRIC HEATING SECTION
1. An electric heating section, with nickel chromium ele-
ments, shall be provided in a range of 5 thru 30 KW, of-
fering two stages of capacity -- 16 KW and above on
208/230 volt heaters and 20 KW and above on 460 and
575 volt heaters.
2. The heating section shall have a primary limit control(s)
and automatic reset, to prevent the heating element sys-
tem from operating at an excessive temperature.
3. The Heating Section assembly shall slide out of the unit
for easy maintenance and service.
4. Units with Electric Heating Sections shall be wired for a
single point power supply with branch circuit fusing
(where required).
UNIT OPERATING CHARACTERISTICS
1. Unit shall be capable of starting and cooling at 125° F
outdoor temperature, exceeding maximum load criteria of
ARI Standard 210/240.
2. The compressor, with standard controls, shall be capable
of cooling down to 45° F outdoor temperature.
ELECTRICAL REQUIREMENTS
All unit power wiring shall enter unit cabinet at a single factory
provided location and be capable of side or bottom entry, to
minimize roof penetrations and avoid unit field modifications.
Separate side and bottom openings shall be provided for the
control wiring.
STANDARD LIMITED WARRANTIES
Compressor-- 5 Years
Elect. Heat. Elem.-- 5 Years
Parts -- 1 Year
OPTIONAL OUTDOOR AIR (Shall be made available by
either/or):
1. ELECTRONIC ENTHALPY AUTOMATIC ECONO-
MIZER -- Outdoor and return air dampers that are inter-
locked and positioned by a fully--modulating, spring--
return damper actuator. The maximum leakage rate for
the outdoor air intake dampers shall not exceed 2%
when dampers are fully closed and operating against a
pressure differential of 0.5 IWG. A unit--mounted potenti-
ometer shall be provided to adjust the outdoor and return
air damper assembly to take in CFM of outdoor air to
meet the minimum ventilation requirement of the condi-
tioned space during normal operation. During econo-
mizer operation, a mixed--air temperature control shall
modulate the outdoor and return air damper assembly to
prevent the supply air temperature from dropping below
55°F. Changeover from compressor to economizer op-
eration shall be provided by an integral electronic en-
thalpy control that feeds input into the basic module. The
outdoor intake opening shall be covered with a rain hood
that matches the exterior of the unit. Water eliminator/fil-
ters shall be provided. Simultaneous economizer/com-
pressor operation is also possible. Dampers shall fully
close on power loss.
2. DUAL INPUT DIFFERENTIAL ELECTRONIC
ENTHALPY AUTOMATIC ECONOMIZER -- Outdoor and
return air dampers that are interlocked and positioned by
a fully--modulating, spring--return damper actuator. The
maximum leakage rate for the outdoor air intake
dampers shall not exceed 2% when dampers are fully
closed and operating against a pressure differential of
0.5 IWG. A unit mounted potentiometer shall be provided
to adjust the outdoor and return air damper assembly to
take in the design CFM of outdoor air to meet the
minimum ventilation requirement of the conditioned
space during normal operation. During economizer
operation, a mixed--air temperature control shall
modulate the outdoor and return air damper assembly to
prevent the supply air temperature from dropping below
55°F. Changeover from compressor to economizer
operation shall be provided by two integral electronic
enthalpy controls -- one that senses outdoor air and one
that senses indoor air. Both enthalpy sensors supply
input to the logic module which modulates both sets of
dampers for maximum economizer savings. The outdoor
intake opening shall be covered with a rain hood that
matches the exterior of the unit. Water eliminator/filters
shall be provided. Simultaneous economizer/compressor
operation is also possible. Dampers shall fully close on
power loss.
OTHER PRE--ENGINEERED ACCESSORIES AVAILABLE
1. ROOF CURB -- 14" AND 8" high, full perimeter knock-
down curb with hinged design for quick assembly.
2. MANUAL OUTDOOR DAMPER -- Provides 0% through
35% or 0% through 100% outdoor air capability (field ad-
justable). Designed for duct mounted side supply/return
applications. Includes a hood and a screen assembly.
3. OUTDOOR COIL GUARD -- Prevents coil damage.
4. BAROMETRIC RELIEF DAMPER -- Contains a rain
hood, air inlet screen, exhaust damper and mounting
hardware. Used to relieve internal air pressure through
the unit during economizer operation.
5. BURGLAR BARS -- Designed to work with above
roofcurbs. Fits duct openings of curb supply and return
air openings.
036-21564-003-A-1005
Unitary Products Group
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