351579-YTS-B-0608
14
Johnson Controls Unitary Products
Heating Lockout on OAT - (75 °F) -
This is the Outside Air
Temperature Setpoint that the control will use to lock out Heating
when the OAT is above this setpoint. There is a one-degree
hysteresis on each side of the setpoint. This parameter is
adjustable between 0 °F and 100 °F with the default set to 75 °F.
Heating Lockout on OAT affects only staged heating, it does not
affect hydronic heat. If the heating is energized when OAT
reaches this setpoint, the Status LED will indicate the lockout
condition immediately, but the control will finish the heating
mode and then lock out the heating.
Note that a Heating Lockout on OAT may occur while the
control is in a heating mode and there is a demand for heating.
If the OAT then decreases below the lockout setting while the
call for several heat stages exists, the heat stages will turn on
simultaneously. This is considered acceptable as this situation
is not expected to occur frequently.
Cooling Lockout on OAT - (45 °F) -
This is the Outside Air
Temperature Setpoint that the control uses to lock out Cooling
when the OAT is below this setpoint. Adjustable from 0 °F to
100 °F, the default is 45 °F.
Unoccupied Heating Setpoint - (60 °F) -
This value is the
Unoccupied Heating Setpoint. It is used in both CV and VAV
mode of operation (in VAV, it controls Unoccupied heating with
a Space Sensor).
Figure 5: Sequence Of Setting The Set Points
The control will attempt to correct wrong temperature overlap
settings; for example, if a change is made that would put
Occupied Heating above Occupied Cooling, the Occupied
Cooling setting will change to stay above the heating setpoint.
Occupied Heating Setpoint - (68 °F) -
This value is the
Occupied Heating Setpoint. It is used only in CV mode of
operation. Its relationship to the related setpoints is as defined
in the Unoccupied Heating Setpoint paragraph above.
Unoccupied Cooling Setpoint - (85 °F) -
This value is the
Unoccupied Cooling Setpoint. It is used in both CV and VAV
mode of operation (in VAV, it controls Unoccupied cooling with a
Space Sensor).
Occupied Cooling Setpoint - (72 °F) -
This value is the
Occupied Cooling Setpoint. It is used only in CV mode of
operation. Its relationship to the related setpoints is as defined
in the Unoccupied Heating Setpoint paragraph above.
[Input] FSI (Hot Water Freeze Protection) - (OFF) -
This
option is used only on rooftop units with hydronic heat
(Hydronic Heat Option is turned ON). Freeze protection should
always be placed on units that use hydronic heating. When the
control senses 24VAC, the control will turn on the Hot Water
valve to 100%. The control will continue to drive the valve at
100% until five minutes after the switch has opened. Then the
valve will revert to normal operation. If the control is operating
the Fan, it will close the Economizer fully until the freeze
condition is over. If the fan is off and the RAT drops below 40 °F,
the Hot Water Valve will turn on 100%.
Supply AirTemp (SAT) Alarm Setpoint for Cooling - (0 °F) -
If
the SAT does not drive below this setpoint when all stages of
compression are operating and 10 minutes has elapsed since
the last compressor was energized, the control will declare a
Cooling SAT Failure Alarm.
The alarm is written to the Error History Buffer. In networked
applications, the alarm flag is readable by the network.
The alarm will reset automatically if the SAT does decrease
below the setpoint (the alarm condition no longer exists), or
when a compressor is turned off (the control does not request
all compressors operate). The SAT Alarm Setpoint for Cooling
can be adjusted from 50 °F - 80 °F. If the value is set to 0 °F
(default) this feature is disabled.
Before the control declares an error, it will read the OAT and the
Economizer position. If the OAT is more than 20 °F warmer than
the setpoint and the Economizer is open more than 20%, the
control will close the Economizer for 10 minutes and then read
the SAT. If the SAT falls below the setpoint, the control will
declare an Economizer Minimum Position alarm. The control
will keep the Economizer closed and finish the Cooling mode.
After the Cooling mode has been satisfied, the control will move
the Economizer back to the minimum position.
Supply Air Temp (SAT) Alarm Setpoint for Heating - (0 °F) -
The SAT must drive above this setpoint when all stages of heating
are operating and 10 minutes has elapsed since the last stage was
energized. If this does not happen, the control will declare a
Heating SAT Failure Alarm. The alarm is written to the Error
History Buffer. In networked applications, the alarm flag is readable
by the network. The alarm will reset automatically if the SAT does
increase above the setpoint (the alarm condition no longer exists),
or when a heating stage is turned off (the control does not request
all heat stages to operate).
The SAT Alarm Setpoint for Cooling can be adjusted from 70 °F -
120 °F. If the value is set to 0 °F (default) this feature is disabled.
Before the control declares an error, it will read the OAT and the
Economizer position. If the OAT is more than 20 °F colder than
the setpoint and the Economizer is open more than 20%, the
control will close the Economizer for 10 minutes and then read
the SAT. If the SAT rises above the setpoint, the control will
declare an Economizer Minimum Position alarm. The control
will keep the Economizer closed and finish the Heating mode.
After the Heating mode has been satisfied, the control will move
the Economizer back to the minimum position.
Unoccupied Override Time Period - (60 min) -
The
Unoccupied Override Time Limit function will determine how
long the unit will operate in the Unoccupied Override mode
when the Override button is pressed on the Space Sensor.
UnOcc.
Htg.
Occ.
Htg.
UnOcc.
Clg.
Occ.
Clg.
