![background image](http://html.mh-extra.com/html/carrier/weatherexpert-50lc/weatherexpert-50lc_installation-instructions-manual_2561507042.webp)
42
Table 15 – W7220 Input/Output with Demand Controlled Ventilation (DCV)
INPUTS
Ref:
FAN SPD*
OUTPUTS
DEMAND
CONTROLLED
VENTILATION
OUTSIDE AIR
Good to
economize?
Y1---I
Y2---I
Mechanical Cooling Stage
Occupancy
OCC Yes
OCC No
Y1---O/1ST
Y2---O/2ND
Outside Air Damper Position
Below set
No
Off
Off
Low
0---v/Off
0---v/Off
VENTMIN L
Closed
On
Off
Low
24---v/On
0---v/Off
VENTMIN L
Closed
On
On
High
24---v/On
24---v/On
VENTMIN H
Closed
Yes
Off
Off
Low
0---v/Off
0---v/Off
VENTMIN L
Closed
On
Off
Low
0---v/Off
0---v/Off
Modulating:
VENTMIN L to
Full---Open
Modulating:
Closed to
Full---Open
On
On
High
2SP DELAY
{
;
24v/On
0---v/Off**
Modulating:
VENTMIN H to
Full---Open
Modulating:
Closed to
Full---Open
Above set
No
Off
Off
Low
0---v/Off
0---v/Off
Modulating:
VENTMIN L to
VENTMAX L
Closed
On
Off
Low
24---v/On
0---v/Off
Modulating:
VENTMIN L to
VENTMAX L
Closed
On
On
High
24---v/On
24---v/On
Modulating:
VENTMIN H to
VENTMAX H
Closed
Yes
Off
Off
Low
0---v/Off
0---v/Off
Modulating:
VENTMIN L to
VENTMAX L
Closed
On
Off
Low
0---v/Off
0---v/Off
Modulating:
VENTMIN L to
Full---Open
Modulating:
Closed to
Full---Open
On
On
High
2SP DELAY
{
;
24v/On
0---v/Off**
Modulating:
VENTMIN H to
Full---Open
Modulating:
Closed to
Full---Open
*
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
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
R
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 to
W7220 input AUX2I; the outside air damper will move to
MIN POS H. Unit heating sequence will follow base unit
control sequences.
Summary of Contents for WeatherExpert 50LC
Page 4: ...4 a50 9584 Fig 2 Unit Dimensional Drawing ...
Page 5: ...5 a50 9585 Fig 2 Unit Dimensional Drawing cont ...
Page 14: ...14 a50 9586 Fig 17 50LC 07 Electro mechanical Control Wiring Diagram ...
Page 15: ...15 a50 9592 Fig 18 50LC 07 RTU Open Control Wiring Diagram ...
Page 16: ...16 a50 9587 Fig 19 50LC 07 SystemVut Control Wiring Diagram ...