Enthalpy Settings - Carrier WeatherMaster 48HC04 Series Installation Instructions Manual

Table 15 — Enthalpy Operation with DCV (CO
DEMAND OUTSIDE AIR
CONTROLLED GOOD TO
VENTILATION (DCV) ECONOMIZE
Below CO set
2
Above CO set
2
*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.
†With stage 3 delay (STG3 DLY) in Advanced setup menu can turn on second stage of mechanical cooling Y2–O after the delay if the call for Y1–I and
Y2–I have not been satisfied.

ENTHALPY SETTINGS

When the OA temperature, enthalpy and dew point are below the
respective set points, the Outdoor Air can be used for economiz-
ing. Figure 56 shows the new single enthalpy boundaries in the
W7220. There are 5 boundaries (set points ES1 through ES5),
which are defined by dry bulb temperature, enthalpy and dew
point.
Refer to Table 16 for ENTH CURVE set point values.
The W7220 calculates the enthalpy and dew point using the OA
temperature and humidity input from the OA enthalpy sensor.
ECONOMIZING
AVAILABLE
NOT AVAILABLE
TEMPERATURE
Y1-I Y2-I
Off Off
On Off
No
On On
Off Off
On Off
Yes
On On
Off Off
On Off
No
On On
Off Off
On Off
Yes
On On
Fig. 56 — Single Enthalpy Curve Boundaries
Sensor) — 1 Speed Fan
2
FAN
Y1-O Y2-O
SPEED
High 0-v/Off 0-v/Off
High 24-v/On 0-v/Off
High 24-v/On 24-v/On
High 0-v/Off 0-v/Off
High 0-v/Off 0-v/Off
High 24-v/On 0-v/Off†
High 0-v/Off 0-v/Off
High 24-v/On 0-v/Off
High 24-v/On 24-v/On
High 0-v/Off 0-v/Off
High 0-v/Off 0-v/Off
DELAY*
High 0-v/Off†
24-v/On
When the OA temperature, OA humidity and OA dew point are
all below the selected boundary, the economizer sets the econo-
mizing mode to YES, economizing is available.
When all of the OA conditions are above the selected boundary,
the conditions are not good to economize and the mode is set to
NO.
Figure 56 shows the 5 current boundaries. There is also a high lim-
it boundary for differential enthalpy. The high limit boundary is
ES1 when there are no stages of mechanical cooling energized and
HL (high limit) when a compressor stage is energized.
38
OCCUPIED UNOCCUPIED
Closed
VENTMIN
Closed
VENTMIN
Closed
VENTMIN
Closed
VENTMIN
Closed to
VENTMIN to
Full-Open
Full-Open
Closed to
VENTMIN to
Full-Open
Full-Open
VENTMIN to
Closed
VENTMAX
VENTMIN L to
Closed
VENTMAX
VENTMIN H to
Closed
VENTMAX
VENTMIN L to
Closed
VENTMAX
Closed to
VENTMIN to
Full-Open
Full-Open
Closed to
VENTMIN to
Full-Open
Full-Open
DUAL ENTHALPY
HIGH LIMIT
SINGLE ENTHALPY
P2 (T,RH)
P1
(T,RH)
ES4 ES3 ES2 ES1
ES5
HL