Enthalpy Settings; Checkout - Bryant Preferred Series Installation Instructions Manual

ECONOMIZING
AVAILABLE
NOT AVAILABLE
TEMPERATURE
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 set points, the Outdoor Air can be used for econ-
omizing. Figure 52 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 13 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 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.
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 52 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.

CHECKOUT

Inspect all wiring connections at the economizer module's ter-
minals, and verify compliance with the installation wiring dia-
grams. For checkout, review the Status of each configured pa-
rameter and perform the Checkout tests.
NOTE: For information about menu navigation and use of the
keypad, see Interface Overview on page 30.
Power Up
After the W7220 module is mounted and wired, apply power.
Fig. 52 — Single Enthalpy Curve Boundaries
Table 13 — Single Enthalpy and Dual Enthalpy High Limit Curves
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
ES5
POINT P1
HUMIDITY
TEMP. (F)
(%RH)
80 36.8
75 39.6
70 42.3
65 44.8
60 46.9
86 38.9
Initial Menu Display
On initial start up, Honeywell displays on the first line and
economizer W7220 on the second line. After a brief pause, the
revision of the software appears on the first line and the second
line will be blank.
Power Loss (Outage or Brownout)
All set points and advanced settings are restored after any pow-
er loss or interruption.
NOTE: All settings are stored in non-volatile flash memory.
Status
Use the Status menu (see Table 7) to check the parameter val-
ues for the various devices and sensors configured.
NOTE: For information about menu navigation and use of the
keypad, see Interface Overview on page 30.
Checkout Tests
Use the Checkout menu (see page 35) to test the damper opera-
tion and any configured outputs. Only items that are config-
ured are shown in the Checkout menu.
NOTE: For information about menu navigation and use of the
keypad, see Interface Overview on page 30.
To perform a Checkout test:
1. Scroll to the desired test in the Checkout menu using the
▲ and ▼ buttons.
2. Press the (Enter) button to select the item. RUN?
appears.
3. Press the (Enter) button to start the test. The unit
pauses and then displays IN PROGRESS. When the test is
complete, DONE appears.
4. When all desired parameters have been tested, press the
(Menu Up) button to end the test.
The Checkout tests can all be performed at the time of installa-
tion or at any time during the operation of the system as a test
that the system is operable.
38
DUAL ENTHALPY
HIGH LIMIT
SINGLE ENTHALPY
P2 (T,RH)
P1
(T,RH)
ES4 ES2 ES1
ES3
POINT P2
HUMIDITY
TEMP. (F)
66.3
63.3
59.7
55.7
51.3
72.4
HL
(%RH)
80.1
80.0
81.4
84.2
88.5
80.3