YORK INTERNATIONAL
30
Stand Alone Control
If the unit is not configured for Thermostat or Zone Sen-
sor operation, the unit will operate in Stand Alone Mode.
In Stand Alone Mode, the OptiLogic™ Controller will
monitor only the Occupied/Unoccupied state. When the
unit is commanded into the Occupied Mode of opera-
tion, the OptiLogic™ Controller will start the Supply Fan.
If the unit is equipped with an Economizer, the Control-
ler will check to see if Outside Air conditions are suit-
able for Economizing. The controller will then use Out-
side Air (when available and suitable) and/or stage com-
pressors up and down, as required, to maintain the VAV
Low SAT Setpoint.
CV SPECIFIC SEQUENCES
Cooling Operation
Thermostat Control
If a 7-wire thermostat (2 Cool/2Heat) controls the unit,
all zone temperature setpoint control is maintained at
the thermostat. With this operation, the unit remains
idle until it receives a stage call from the Thermostat. If
“G” is called from the thermostat, the Supply Fan will
start and all occupied functions (if equipped), i.e. venti-
lation, economizer, etc. will be allowed to operate.
Stage 1 (“Y1”) Call
If Y1 is called and the unit is equipped with an econo-
mizer, the control will check to see if the Outside Air is
suitable for economizing. If conditions are suitable for
economizing, the control will control the economizer and
stage up compressors, as required, to maintain a high
SAT setpoint. If conditions are not suitable for econo-
mizing or not equipped with an economizer, the control
will stage up 50% of the compressors. This shall be
maintained until Stage 1 is deactivated or Stage 2 is
called.
Stage 2 (“Y2”) Call
If Y2 is called and the unit is equipped with an econo-
mizer, the control will check to see if the Outside Air is
suitable for economizing. If conditions are suitable for
economizing, the control will control the economizer and
stage up compressors, as required, to maintain a LOW
SAT setpoint. If conditions are not suitable for econo-
mizing or not equipped with an economizer, the control
will stage up 100% of the compressors. This shall be
maintained until Stage 2 is deactivated.
Zone Sensor Control
If a zone sensor controls the unit, the OptiLogic™ con-
troller shall maintain all zone temperature setpoints.
These setpoints are user selectable at the OptiLogic™
User Interface.
When a zone sensor is used for control, the OptiLogic™
unit controller will monitor the temperature within the
space and control the unit accordingly. A closed-loop
staging algorithm is used to stage compressors up and
down as required to maintain the desired zone tempera-
ture setpoint. If the unit is equipped with an economizer,
Outside Air conditions are continuously monitored by the
control to determine if conditions are suitable for econo-
mizing. If conditions are suitable for economizing, the
OptiLogic™ controller will modulate the Outside Air
damper in addition to staging compressors up and down
to maintain the zone temperature setpoint.
Controls
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