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Table 19 – W7220 Input/Output with Demand Controlled Ventilation (DCV)
INPUTS
DEMAND
OUTSIDE AIR
CONTROLLED
Good to
VENTILATION
economize?
No
Below set
Yes
No
Above set
Yes
*
Fan Speed for reference only; this is not an input or output function of the W7220.
{
See Menu ADV SETUP ---> 2SP FAN DELAY for details.
**
See Menu ADV SETUP ---> STG# DLY. With Stage 3 delay enabled, control can turn on 2
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.
Ref:
FAN SPD*
Y1--- I
Y2--- I
Off
Off
Low
On
Off
Low
On
On
High
Off
Off
Low
On
Off
Low
2SP DELAY
On
On
High
Off
Off
Low
On
Off
Low
On
On
High
Off
Off
Low
On
Off
Low
2SP DELAY
On
On
High
OUTPUTS
Mechanical Cooling Stage
Y1--- O/1ST
Y2--- O/2ND
0--- v/Off
0--- v/Off
24--- v/On
0--- v/Off
24--- v/On
24--- v/On
0--- v/Off
0--- v/Off
0--- v/Off
0--- v/Off
{
;
0--- v/Off **
24v/On
0--- v/Off
0--- v/Off
24--- v/On
0--- v/Off
24--- v/On
24--- v/On
0--- v/Off
0--- v/Off
0--- v/Off
0--- v/Off
{
;
0--- v/Off **
24v/On
nd
stage of cooling Y2 ---O after delay if the call for Y2 ---I has not
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- -
Heating With EconoMi$er
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 to
W7220 input AUX2I; the outside air damper will move to
MIN POS H. Unit heating sequence will follow base unit
control sequences.
54
Occupancy
OCC Yes
OCC No
Outside Air Damper Position
VENTMIN L
Closed
VENTMIN L
Closed
VENTMIN H
Closed
VENTMIN L
Closed
Modulating:
Modulating:
VENTMIN L to
Closed to
Full--- Open
Full--- Open
Modulating:
Modulating:
VENTMIN H to
Closed to
Full--- Open
Full--- Open
Modulating:
VENTMIN L to
Closed
VENTMAX L
Modulating:
VENTMIN L to
Closed
VENTMAX L
Modulating:
VENTMIN H to
Closed
VENTMAX H
Modulating:
VENTMIN L to
Closed
VENTMAX L
Modulating:
Modulating:
VENTMIN L to
Closed to
Full--- Open
Full--- Open
Modulating:
Modulating:
VENTMIN H to
Closed to
Full--- Open
Full--- Open
1
/
minutes.
2
R
X —
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