Carrier 50HCQ07 Installation Instructions Manual page 43

Table 18 — Enthalpy Operation, No Demand Controlled Ventilation (DCV) (CO
OUTSIDE AIR
DCV GOOD TO
ECONOMIZE?
No
None
Yes
*With 2SP FAN DELAY (Advanced Setup Menu) when in the
economizing mode there is a delay for the high speed fan to try to
satisfy the call for second stage cooling by turning on the fan to high
and opening the OA damper 100% before the first stage mechanical
cooling is enabled.
Table 19 — Enthalpy Operation, with Demand Controlled Ventilation (DCV) (CO
OUTSIDE AIR
DCV GOOD TO
ECONOMIZE?
No
Below Set
Yes
No
Above Set
Yes
*With 2SP FAN DELAY (Advanced Setup Menu) when in the
economizing mode there is a delay for the high speed fan to try to
satisfy the call for second stage cooling by turning on the fan to high
and opening the OA damper 100% before the first stage mechanical
cooling is enabled.
Table 20 — Single Enthalpy and Dual Enthalpy High Limit Curves
ENTHALPY TEMP. DRY
CURVE BULB (F)
ES1 80
ES2 75
ES3 70
ES4 65
ES5 60
HL 86
Enthalpy Settings
When the OA temperature, enthalpy and dew point are below
the respective setpoints, the Outdoor Air can be used for econ-
omizing. Figure 50 shows the new single enthalpy boundaries
in the W7220. There are 5 boundaries (setpoints ES1 through
ES5), which are defined by dry bulb temperature, enthalpy and
dew point.
Refer to Table 20 for ENTH CURVE setpoint values.
The W7220 calculates the enthalpy and dew point using the
OA temperature and humidity input from the OA enthalpy sen-
sor. When the OA temperature, OA humidity and OA dew
point are all below the selected boundary, the economizer sets
the economizing mode to YES, economizing is available.
Y1-I Y2-I FAN SPEED
Off Off Low
On Off Low
On On High
Off Off Low
On Off Low
On On High
Y1-I Y2-I FAN SPEED
Off Off Low
On Off Low
On On High
Off Off Low
On Off Low
On On High
Off Off Low
On Off Low
On On High
Off Off Low
On Off Low
On On High
TEMP. ENTHALPY
DEWPOINT (F) (btu/lb/da)
60 28.0
57 26.0
54 24.0
51 22.0
48 20.0
66 32.4
Y1-O Y2-O OCCUPIED
0-v/Off 0-v/Off MIN POS L
24-v/On 0-v/Off MIN POS L
24-v/On 24-v/On MIN POS H
0-v/Off 0-v/Off MIN POS L
0-v/Off 0-v/Off MIN POS L to Full-Open
DELAY*
0-v/Off † MIN POS H to Full-Open
24-v/On
With stage 3 delay (STG3 DLY) in Advanced setup menu, second
†
stage of mechanical cooling Y2-O can be turned on after the delay if the
calls for Y1-I and Y2-I have not been satisfied.
Y1-O Y2-O OCCUPIED
0-v/Off 0-v/Off VENTMIN L
24-v/On 0-v/Off VENTMIN L
24-v/On 24-v/On VENTMIN H
0-v/Off 0-v/Off VENTMIN L
0-v/Off 0-v/Off VENTMIN L to Full-Open
24-v/On 0-v/Off VENTMIN H to Full-Open
†
0-v/Off 0-v/Off VENTMIN L to VENTMAX
24-v/On 0-v/Off VENTMIN L to VENTMAX
24-v/On 24-v/On VENTMIN H to VENTMAX
0-v/Off 0-v/Off VENTMIN L to VENTMAX
0-v/Off 0-v/Off VENTMIN L to Full-Open
DELAY*
0-v/Off † VENTMIN H to Full-Open
24-v/On
† With stage 3 delay (STG3 DLY) in Advanced setup menu, second
stage of mechanical cooling Y2-O can be turned on after the delay if the
calls for Y1-I and Y2-I have not been satisfied.
POINT P1
HUMIDITY
TEMP. (F)
(%RH)
80 36.8
75 39.6
70 42.3
65 44.8
60 46.9
86 38.9
When all of the OA conditions are above the selected bound-
ary, the conditions are not good to economize and the mode is
set to NO.
Figure 50 shows the 5 current boundaries. There is also a high
limit boundary for differential enthalpy. The high limit bound-
ary is ES1 when there are no stages of mechanical cooling en-
ergized and HL (high limit) when a compressor stage is
energized.
43
Sensor) — 2 Speed Fan
2
UNOCCUPIED
Closed
Closed
Closed
Closed
Closed to Full-Open
Closed to Full-Open
Sensor) — 2 Speed Fan
2
UNOCCUPIED
Closed
Closed
Closed
Closed
Closed to Full-Open
Closed to Full-Open
Closed
Closed
Closed
Closed
Closed to Full-Open
Closed to Full-Open
POINT P2
HUMIDITY
TEMP. (F)
(%RH)
66.3 80.1
63.3 80.0
59.7 81.4
55.7 84.2
51.3 88.5
72.4 80.3