FORM 100.50-NOM7 (808)
23
JOHNSON CONTROLS
3
TABLE 3 – MODES OF OPERATION
Heating Cooling
Control
Occupied Unoccupied Occupied Unoccupied
Thermostat Controller Occupied input Controller Occupied input Controller Occupied input is ON
is ON (energized by ‘stat is OFF (deenergized by (energized by ‘stat occ. output,
occ. output, or by an ‘stat occ. output, or by or by an external command).
external command). an external command). ‘stat uses its programmed
‘stat uses its Economizer damper is at occupied clg. setpoint. Supply
programmed occupied 0% Control is same as fan controlled by ‘stat’s G output
htg. Setpoint. Supply fan occupied heating, except Economizer damper at
controlled by ‘stat’s G ‘stat uses its programmed min. position, may
output. programmed unoccupied modulate open if free cooling is
Economizer damper at heating setpoint. being used.
programmed min. position. Mechanical cooling mode:
‘stat W1, W2 outputs ‘stat Y1, Y2 outputs control
control heating stages 1 stage 1 and 2 compressors.
and 2. Economizer mode:
If hydronic heat, ‘stat W1, ‘stat Y1, Y2 outputs select High
W2 outputs select and Low programmed
programmed “Hydronic Economizer SAT setpoints, SAT
heat 1
st
and 2
nd
stage controlled by economizer
Setpoints. control algorithm.
Space Controller Occupied input Controller Occupied input Controller Occupied input is ON
Sensor is ON (energized by an is OFF (deenergized by (energized by an external
external command). an external command). command).
Space temperature is Economizer damper is at Space temperature is controlled
controlled to a 0% Supply fan is in to a programmed occupied clg.
programmed occupied “Auto” mode (i.e. goes o setpoint.
htg. setpoint. when space is satised). For supply fan, setting of the
For supply fan, setting of Control is same as parameter “Fan ON mode with
the parameter “Fan ON occupied heating, except the Sensor Option” determines
mode with the Sensor space temperature is if the supply fan is ON
Option” determines if the controlled to a continuously, or is in “Auto”
supply fan is ON programmed unoccupied mode (i.e. goes o when space
continuously, or is in heating setpoint. is satised).
“Auto” mode (i.e. goes o Economizer damper at
when space is satised). programmed min. position, may
Economizer damper at modulate open if free cooling is
programmed min. position. being used.
Heating is controlled by a Mechanical cooling mode:
PI algorithm that controls Cooling is controlled by a PI
staging of heat stages algorithm that controls
and modulates duty cycle compressor staging and
of the highest numbered modulates duty cycle of the
running heating stage. highest numbered running
If hydronic heat, space compressor.
control algorithm selects Economizer mode:
programmed “Hydronic Space control algorithm selects
Heat 1
st
Stage SAT High and Low programmed
Setpoint” and “Hydronic Economizer SAT setpoints, SAT
Heat 2
nd
Stage SAT controlled by economizer
Setpoint”. control algorithm.
Controller Occupied input is
OFF (deenergized by ‘stat
occ. output, or by an external
command).
Economizer damper is at 0%
(damper may modulate open
if free cooling is being used).
Control is same as occupied
cooling, except ‘stat uses
its programmed unoccupied
cooling setpoint.
Controller Occupied input
is OFF (deenergized by an
external command).
Economizer damper is at 0%
(damper may modulate open
if free cooling is being used).
Supply fan is in “Auto” mode
(i.e. goes o when space is
satised).
Control is same as occupied
cooling with a space sensor,
except space temperature is
controlled to a programmed
unoccupied clg. setpoint.