York WR300 User Manual

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262292-YTG-B-0107
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Unitary Products Group
FEATURES
All models are available with a wide variety of factory-mounted 
options such as stainless steel heat exchangers, phase 
monitor, dirty filter switch, and coil guard to make them suitable 
for almost every application.
All units are self-contained and assembled on full perimeter 
base rails with holes in the four corners for overhead rigging. 
Every unit is completely piped, wired, charged and tested at the 
factory to simplify the field installation and to provide years of 
dependable operation.
All models (including those with an economizer) are suitable for 
either bottom or horizontal duct connections. Models with 
factory installed power exhaust are suitable for bottom 
duct connections only
. For bottom duct, you remove the 
sheet metal panels from the supply and return air openings 
through the base of the unit. For horizontal duct, you replace 
the supply and return air panels on the rear of the unit with a 
side duct flange accessory.
All models are available with these “factory mounted” outdoor 
air damper options:
• Single enthalpy economizer
• Single enthalpy economizer with power exhaust
• Motorized outdoor air damper
A fixed outdoor air intake assembly will be shipped in the return 
air compartment of all units ordered without an economizer or 
motorized outdoor air damper option. The assembly includes a 
rain hood with a damper that can be set for 10, 15 or 25% 
outdoor air. With bottom duct connections, the intake damper 
assembly should be mounted over the opening in the return air 
panel. With horizontal ductwork, it should be mounted on the 
return air duct.
All supply air blowers are equipped with a belt drive that can be 
adjusted to meet the exact requirements of the job. A high static 
drive option is available for applications with a higher CFM and/
or static pressure requirement. A variable air volume (VAV) 
option using a variable frequency drive is available for 
applications requiring a constant supply duct pressure. A 
differential pressure transducer is used to monitor supply duct 
static pressure and return a speed reference signal to the VFD 
to control the output of the indoor blower motor.
All compressors include scroll compressors and internal 
pressure relief. Every refrigerant circuit includes an expansion 
valve, a liquid line filter-drier, a discharge line high pressure 
switch and a suction line with a freezestat and low pressure/
loss of charge switch to protect all system components. A hot 
gas bypass option, consisting of an adjustable compressor 
discharge bypass valve, is available for low cooling load 
applications.
• Simplicity® 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 assistance. Optionally, 
the control board can be programmed 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.
• Lead-Lag - An integrated Lead-Lag option allows equal 
run time hours on all compressors, thereby extending the 
life of all compressors. This option is selectable on the unit 
control board.
• Fan Delays - Fan on and fan off delays are fully 
programmable. 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 control 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.
All units have long lasting powder paint cabinets with 1000 hour 
salt spray test approval under ASTM-B117 procedures.
All models are CSA approved.
• Warranty - All models include a one-year limited parts 
warranty on the complete unit. Compressors and electric 
heater elements carry a five-year warranty. Gas heat 
exchangers carry a 10-year parts warranty.
• Gas Heat Operation - All gas heat units are built with two 
heating sections for two equal stages of capacity control. 
Each section includes a durable heat exchanger with 
aluminized steel or optional stainless steel tubes, a 
redundant gas valve, spark ignition, power venting, an 
ignition module for 100% shut-off and all of the safety 
controls required to meet the latest ANSI standards.
The gas supply piping can be routed into the heating 
compartment through a hole in the base pan of the unit or 
through a knockout in the piping panel on the front of the 
unit.