Carrier 69NT40-541-300, Operation And Service, Page: 34 / 152

T-318 3 − 2
3.1.1 Keypad
The keypad (Figure 3-2) is mounted on the right-hand
side of the control box. The keypad consists of 11 push
button switches that act as the user’s interface with the
controller. Descriptions of the switch functions are
provided in Table 3-1.
ENTER
BATTERY
POWER
MANUAL
DEFROST/
INTERVAL
CODE
SELECT
PRE
TRIP
ALARM
LIST
ALT.
MODE
RETURN
SUPPLY
C
F
Figure 3-2 Keypad
3.1.2 Display Module
The display module (Figure 3-3) consists of five digital
displays and seven indicator lights. Indicator lights
include:
1. COOL − White LED: Energized when the refrigerant
compressor is energized.
2. HEAT − Orange LED: Energized to indicate heater
operation in heat mode, defrost mode, or
dehumidification.
3. DEFROST − Orange LED: Energized when the unit
is in the defrost mode.
4. IN RANGE − Green LED: Energized when the con-
trolled temperature probe is within specified tolerance
of set point.
Table 3-1 Keypad Function
KEY FUNCTION
CODE
SELECT
Accesses function codes.
PRE
TRIP
Displays the pre-trip selection menu.
Discontinues pre-trip in progress.
ALARM
LIST
Displays alarm list and clears the
alarm queue.
MANUAL
DEFROST /
INTERVAL
Displays selected defrost mode. De-
pressing and holding the Defrost in-
terval key for five seconds will initiate
defrost using the same logic as if the
optional manual defrost switch was
toggled on.
ENTER
Confirms a selection or saves a
selection to the controller
Arrow Up
Change or scroll a selection upward.
Pre-trip advance or test interruption.
Arrow Down Change or scroll a selection down-
ward. Pre-trip repeat backward
RETURN /
SUPPLY
Displays non-controlling probe tem-
perature (momentary display).
Celsius /
Fahrenheit
Displays alternate English/Metric
scale (momentary display). When set
to degrees Fahrenheit, pressure is
displayed in psig and vacuum in “/hg.
“P” appears after the value to indi-
cate psig and “i” appears for inches
of mercury.
When set to degrees Celsius, pres-
sure readings are in bars. “b” ap-
pears after the value to indicate bars.
BATTERY
POWER
Initiate battery backup mode to allow
set point and function code selection
if AC power is not connected.
ALT
MODE
This key is pressed to switch the
functions from the temperature soft-
ware to the DataCORDER Software.
The remaining keys function the
same as described above except the
readings or changes are made to the
DataCORDER programming.
NOTE
The controlling probe in perishable range is the
SUPPLY air probe and the controlling probe in
frozen range is the RETURN air probe.
5. SUPPLY − Yellow LED: Energized when the supply
air probe is used for control. When this LED is
illuminated, the temperature displayed in the AIR
TEMPERATURE display is the reading at the supply
air probe. This LED will flash if dehumidification or
humidification is enabled.
6. RETURN − Yellow LED: Energized when the return
air probe is used for control. When this LED is illumi-
nated, the temperature displayed in the AIR TEMPER-
ATURE display is the reading at the return air probe.
This LED will flash if dehumidification or humidifica-
tion is enabled.
7. ALARM − Red LED: Energized when an active or an
inactive shutdown alarm is in the alarm queue.