York PREDATOR MagnaDRY DR090, Technical Manual

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246721-YTG-C-0606
6 Unitary Products Group
return is desired, the installer simply removes the two
side duct covers from the outside of the unit and installs
them over the down shot openings. No panel cutting is
required. Convertible airflow design allows maximum
field flexibility and minimum inventory.
• System Protection - Suction line freezestats are sup-
plied on all units to protect against loss of charge and coil
frosting when the economizer operates at low outdoor air
temperatures while the compressors are running. Every
unit has solid-core liquid line filter-driers and high and low-
pressure switches. Internal compressor protection is stan-
dard on all compressors. Crankcase heaters are standard
on reciprocating compressors. Scroll compressors do not
require crankcase heaters. Phase Monitors are standard
on units with scroll compressors. This accessory monitors
the incoming power to the unit and protects the unit from
phase loss and reversed phase rotation.
• Advanced Controls - Simplicity ® control boards have
standardized a number of features previously available
only as options or by utilizing additional controls.
• Low Ambient - An integrated low-ambient control
allows all units to operate in the cooling mode down
to 0
°
F outdoor ambient without additional assis-
tance. Optionally, the control board can be pro-
grammed to lockout the compressors when the
outdoor air temperature is low or when free cooling
is available.
• Anti-Short Cycle Protection - To aid compressor
life, an anti-short cycle delay is incorporated into the
standard controls. Compressor reliability is further
ensured by programmable minimum run times. For
testing, the anti-short cycle delay can be temporarily
overridden with the push of a button.
• Fan Delays - Fan on and fan off delays are fully pro-
grammable. Furthermore, the heating and cooling
fan delay times are independent of one another. All
units are programmed with default values based
upon their configuration of cooling and heat.
• Safety Monitoring - The control board monitors the
high and low-pressure switches, the freezestats, the
gas valve, if applicable, and the temperature limit
switch on gas and electric heat units. The unit con-
trol board will alarm on ignition failures, compressor
lockouts and repeated limit switch trips.
• Nuisance Trip Protection and Strikes - To prevent
nuisance trouble calls, the control board uses a
“three times, you’re out” philosophy. The high and
low-pressure switches and the freezestats must trip
three times within two hours before the unit control
board will lock out the associated compressor.
• On Board Diagnostics - Each alarm will energize a
trouble light on the thermostat, if so equipped, and
flash an alarm code on the control board LED. Each
high and low-pressure switch alarm as well as each
freezestat alarm has its own flash code. The control
board saves the five most recent alarms in memory,
and these alarms can be reviewed at any time.
Alarms and programmed values are retained
through the loss of power.
• Reliable – From the beginning – All units undergo com-
puter automated testing before they leave the factory.
Units are tested for refrigerant charge and pressure, unit
amperage, and 100% functionality. For the long term –
All Predator
®
units are painted with a long lasting, pow-
der paint that stands up over the life of the unit. The paint
used has been proven by a 1000 hour salt spray test.
• Flexible Placement – All models and configurations
share the same cabinet/footprint and thus the same roof
curb. You have the flexibility to set one curb and choose
the correct tonnage size and heating option after the
internal loads have been determined.
To further simplify planning and installation, Predator
®
cabinets are designed to fit your roof. With the optional
roof curb, the unit ductwork is designed to fit around 24”
on-center joists or between 48” on-center joists.
The drain pan can be rotated to drain to either the front
or the rear of the unit. Additionally, the drain pan can be
fitted to drain through the roof curb. As it is sometimes
difficult to have a level installation, the drain pan features
a generous slope to ensure proper drainage.
• Full Perimeter Base Rails – The permanently attached
base rails provide a solid foundation for the entire unit and
protect the unit during shipment. The rails offer forklift
access from 3 sides, and rigging holes are available so that
an overhead crane can be used to place the units on a roof.
• Easy Installation – Gas and electric utility knockouts are
supplied in the unit underside as well as the side of the unit.
A clearly identified location is provided to mount a field sup-
plied electrical disconnect switch. Utility connections can be
made quickly and with a minimum amount of field labor.
All units are shipped with 2” throw-away filters installed.
• Wide Range of Indoor Airflows – All indoor fan motors
are belt-drive type providing maximum flexibility to han-
dle most airflow requirements. For high static applica-
tions, factory installed alternate indoor fan motors are
available. With the optional indoor fan motor, all units can
supply nominal airflow at a minimum of 1.5” ESP.
• Warranty - All models include a 1-year limited warranty
on the complete unit. Compressors and electric heater
elements each carry a 5-year warranty. Aluminized steel
and stainless steel tubular heat exchangers carry a 10-
year warranty.
FACTORY INSTALLED OPTIONS
YORK
®
offers several equipment options factory installed, for
the Predator
®
line.
• Optional Factory Installed Economizers - Predator
units offer a variety of optional factory installed econo-
mizers with low leak dampers. The outdoor air enthalpy
sensor enables economizer operation if the outdoor
enthalpy is less than the setpoint of the economizer logic
module. See Table 38 to determine the correct econo-
mizer for your application.