Bryant 548J - Manual (Page 62)

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Economizer
Economizer Exists
This point tells the controller if there is an economizer
installed on the unit.
Factory Default = NO if no economizer
YES if there is an economizer installed
Economizer Minimum Position
This defines the lowest economizer position when the
indoor fan is running and the building is occupied.
Factory Default = 20%
Range = 0--100 %
Economizer High OAT Lockout
If the outdoor air temperature rises above this value,
economizer cooling will be disabled and dampers will
return and stay at minimum position.
Factory Default = 75_F
Range = 55--80_F
Power Exhaust Setpt
When the economizer damper position opens above this
point the power exhaust operation will begin. When the
damper position falls 10% below the setpoint, the power
exhaust will shutdown.
Factory Default = 50%
Range = 20--90 %
NOTE: This point is only used when Continuous Occ
Exhaust = NO
Continuous Occ Exhaust
This point tells the controller when to run the power
exhaust if equipped on the unit. If set to YES, the power
exhaust will be on all the time when in occupied mode
and will be off when in unoccupied mode. If set to NO the
power exhaust will be controlled by the Power Exhaust
Setpoint.
Factory Default = NO
IAQ
Max Differential CO
2
Setpt
If the difference between indoor an outdoor air quality
becomes greater then this value the damper position will
stay at the IAQ Greatest Min Dmpr Pos. configuration
point
Factory Default = 650 PPM
Range = 300--950 PPM
IAQ Greatest Min Dmpr Pos.
This is the greatest minimum position the economizer will
open to while trying to control the indoor air quality, CO
2
differential.
Factory Default = 50% open
Range = 10--60% open
Clockset
This submenu screen allows you to set the date and time
manually. The Daylight Savings Time (DST) can also be
changed here. The date and time is automatically set when
ever software is downloaded. The clock is a 24 hour clock
and not am/pm. The time should be verified (and maybe
changed) according to unit location and time zone.
Factory Default = Eastern Standard Time
USERPW
This submenu screen allows you to change the user
password to a four number password of choice. The User
password change screen is only accessible with the
Administrator Password (1111). The ADMIN password
will always override the user password.
OPERATING SEQUENCE
Indoor (Supply) Fan
Continuous fan operation is selected at the thermostat.
Terminal G is energized. Defrost Board (DFB) receives
this signal at P2--3 and it issues an output at P3--9.
04A--06A, Standard Static Drive option: 24--v signal at
P3--9 is applied to direct--drive motor communication
signal terminal. Direct--drive motor starts and runs.
All Belt--Drive Fan options: Contactor coil IFC is
energized; indoor fan motor starts.
Fan runs continuously until fan selection at thermostat is
changed to AUTO. When the selector switch is switched
to AUTO, the input at P2--3 is removed and the output at
P3--9 is removed; IFC is de--energized and IFM stops. If
the fan selection is AUTO, indoor fan operation will be
initiated by the DFB through P3--9 when Cooling or
Heating sequence is initiated. Termination of fan
operation will be delayed by 30 secs (if Fan Delay is
configured to ON) after Cooling or Heating sequence is
ended
Base Unit Controls
Cooling, Units Without Economizer
Continuous fan operation is selected at the thermostat.
Terminal G is energized. Defrost Board (DFB) receives
this signal at P2--3 and it issues an output at P3--9.
04A--06A, Standard Static Drive option: 24--v signal at
P3--9 is applied to direct--drive motor communication
signal terminal. Direct--drive motor starts and runs.
All Belt--Drive Fan options: Contactor coil IFC is
energized; indoor fan motor starts.
Fan runs continuously until fan selection at thermostat is
changed to AUTO. When the selector switch is switched
to AUTO, the input at P2----3 is removed and the output at
P3--9 is removed; IFC is de--energized and IFM stops. If
the fan selection is AUTO, indoor fan operation will be
initiated by the DFB through P3----9 when Cooling or
Heating sequence is initiated. Termination of fan
operation will be delayed by 30 secs (if Fan Delay is
configured to ON) after Cooling or Heating sequence is
ended.
The outdoor fan motors run continuously while unit is in
Stage 1 or Stage 2 cooling.
08D–09D: If Stage 1 cooling does not satisfy the space
load, the space temperature will rise until thermostat calls
for Stage 2 cooling (Y2 closes). DFB receives this input
at P2--4. It issues outputs at P3--6 (RVS2) and P3--8
(COMP2). Reversing valve 2 switches to Cooling
548J