43
Table 16 – W7220 Input’/Output with Demand Control Ventilation (DCV)
INPUTS
Ref:
FAN
SPD
(a)
OUTPUTS
DEMAND
CONTROL
VENTILATION
OUTSIDE AIR
Good to
economize?
Y 1 --- I Y 2 --- I
Mechanical Cooling Stage
Occupancy
OCC Yes OCC No
Y 1 --- O / 1 S T Y 2 --- O / 2 N D Outside Air Damper Position
Below set
No
Off Off Low 0 --- v / O f f 0 --- v / O f f VENTMIN L Closed
On Off Low 2 4 --- v / O n 0 --- v / O f f VENTMIN L Closed
On On High 2 4 --- v / O n 2 4 --- v / O n VENTMIN H Closed
Yes
Off Off Low 0 --- v / O f f 0 --- v / O f f VENTMIN L Closed
On Off Low 0 --- v / O f f 0 --- v / O f f
Modulating:
VENTMIN L to
F u l l --- O p e n
Modulating:
Closed to
F u l l --- O p e n
On On High
2SP DELAY (b);
24v/On
0 --- v / O f f ( c )
Modulating:
VENTMIN H to
F u l l --- O p e n
Modulating:
Closed to
F u l l --- O p e n
Above set
No
Off Off Low 0 --- v / O f f 0 --- v / O f f
Modulating:
VENTMIN L to
VENTMAX L
Closed
On Off Low 2 4 --- v / O n 0 --- v / O f f
Modulating:
VENTMIN L to
VENTMAX L
Closed
On On High 2 4 --- v / O n 2 4 --- v / O n
Modulating:
VENTMIN H to
VENTMAX H
Closed
Yes
Off Off Low 0 --- v / O f f 0 --- v / O f f
Modulating:
VENTMIN L to
VENTMAX L
Closed
On Off Low 0 --- v / O f f 0 --- v / O f f
Modulating:
VENTMIN L to
F u l l --- O p e n
Modulating:
Closed to
F u l l --- O p e n
On On High
2SP DELAY (b);
24v/On
0 --- v / O f f ( c )
Modulating:
VENTMIN H to
F u l l --- O p e n
Modulating:
Closed to
F u l l --- O p e n
(a)
Fan Speed f o r reference only; tins is not an input or output fun ction of the W7220
(b)
See Menu ADV SET U P ---> 2SP FAN DELAY for details
(c)
See Menu ADV SET U P ---> STG# DLY. With Stage 3 delay enabled, control can turn on 2
nd
stage of cooling Y2--- O after delay if the call for Y2---I has not
been satisfied.
As space temperature falls, the thermostat will remove its
call for second stage cooling; ISC terminal Y2 call is
removed. The supply fan motor remains High Speed. The
outside air damper limit is repositioned to between MIN
POS L and 100% open. Second stage cooling (Compressor
1 operation) stops. As space temperature continues to fall
and space cooling load is satisfied, the thermostat will
remove its call for first stage cooling; ISC terminal Y1
call is removed. The W7220 input Y1--I is removed; free
cooling mode ends. Outside air damper will remain at
MIN POS L if supply fan remains in operation (CONT
FAN) or to closed if supply fan stops (AUTO FAN).
Should 100% outside air and second stage cooling
(Compressor 1 operation) not be capable of satisfying the
space cooling load, space temperature will rise and the
thermostat will call for third stage cooling: ISC terminal
Y3 is also energized, starting third stage cooling
(Compressor 2 operation). The supply fan motor will
remain at High Speed. The Y3 demand is received at
W7220 input Y2--I. The outdoor air damper position will
modulate from MIN POS H to 100% Open to maintain
SAT at MAT SET concurrent with Compressor 2
operation.
As space temperature falls, the thermostat will remove its
call for third stage cooling; ISC terminal Y3 call is removed.
The supply fan will remain at High Speed. The W7220 input
Y2--I is also removed; the outside air damper is repositioned
to modulate from MIN POS L to 100% Open, third stage
cooling (Compressor 2 operation) stops.
Power Exhaust: If accessory power exhaust is installed,
the power exhaust fan motors will be energized by the
economizer control as the dampers open above the
setpoint EXH1 SET L during Low Speed operation or
EXH1 SET H during High Speed fan operation. The
EXH1 output will be de--energized as the dampers close
below the EXH1 setpoint value.
Damper movement from full closed to full open (or vice
versa) will take approximately 1--
1
/
2
minutes.
Heating With EconoMi$er X —
When the space temperature calls for heat (W1 closes),
ISC terminal W1 is energized. The supply fan will start
and run in High Speed. The W1 signal will connect
toW7220 input AUX2I; the outside air damper will move
to MIN POS H. Unit heating sequence will follow base
unit control sequences.
48HC48LC
To Next Page
Loading...
