PRODUCT DESIGN
16
A 3/4" - 14 NPT drain connector is provided for removal of
condensate water from the indoor coil. In order to provide
proper condensate flow, do not reduce the drain line size.
NOTE:
Tighten drain to a maximum torque of 10 in-lbs.
Refrigerant flow control is achieved by use of thermostatic
expansion valves (TXV) or flowrator.
The single phase models use permanent split capacitors
(PSC) design compressors. Starting components are there-
fore not required. A low MFD run capacitor assists the
compressor to start and remains in the circuit during opera-
tion.
A/GPG three phase units use three phase compressors.
Starting components and run capacitors are therefore not
required.
A/GPG Package Gas Units are designed for outdoor instal-
lations only in either residential or light commercial applica-
tions and are available in 2, 2.5, 3, 3.5, 4 & 5 ton sizes. They
are designed for 208/230 volt single phase applications or
208/230 volt 3 phase applications.
The connecting ductwork (Supply and Return) can be con-
nected for either horizontal or vertical airflow. In the vertical
application, a matching Roof Curb is recommended.
A return air filter must be installed behind the return air grille(s)
or provision must be made for a filter in an accessible location
within the return air duct (3 phase models have an internal
downflow filter rack). The minimum filter area should not be
less than those sizes listed in the Specification Section.
Under no circumstances should the unit be operated without
return air filters.
A/GPG model units use either PSC or X13 type indoor blower
motors. X-13 motors are constant torque motors with very low
power consumption and are energized by a 24V signal from
the ignition control board. The X-13 features an integrated
control module.
Air for condensing (cooling cycle) is drawn through the
outdoor coil by a propeller fan, and is discharged vertically out
the top of the unit. The outdoor coil is designed for .0 static.
No additional restriction (ductwork) shall be applied.
Conditioned air is drawn through the filter(s), field installed,
across the coil and back into the conditioned space by the
indoor blower.
Most A/GPG series package units use the Compliant Scroll
compressor; there are a number of design characteristics
which are different from the traditional reciprocating compres-
sor.
- Due to their design Scroll compressors are inherently
more tolerant of liquid refrigerant.
NOTE
: Even though the
compressor section of a Scroll compressor is more
tolerant of liquid refrigerant, continued flood back or
flooded start conditions may wash oil from the bearing
surfaces causing premature bearing failure.
- These Scroll compressors use "POE" or polyolester oil
which is NOT compatible with mineral oilbased lubri-
cants like 3GS. "POE" oil must be used if additional oil
is required.
- Compliant scroll compressors perform “quiet” shutdowns
that allow the compressor to restart immediately without
the need for a time delay. This compressor will restart
even if the system has not equalized.
- Operating pressures and amp draws may differ from
standard reciprocating compressors. This information
may be found in the “Cooling Performance Data” section.
Some models of the A/GPG15 series package units use a 2
stage scroll compressor. The basic scroll design has been
modified with the addition of an internal unloading mecha-
nism that opens a by-pass port in the first compression
pocket, effectively reducing the displacement of the scroll.
The opening and closing of the by-pass port is controlled by
an internal electrically operated solenoid.
The ZPS modulated scroll uses a single step of unloading
to go from full capacity to approximately 67% capacity. A
single speed, high efficiency motor continues to run while
the scroll modulates between the two capacity steps.
A scroll is an involute spiral which, when matched with a
mating scroll form as shown, generates a series of crescent
shaped gas pockets between the two members.
During compression, one scroll remains stationary (fixed
scroll) while the other form (orbiting scroll) is allowed to orbit
(but not rotate) around the first form.
