Thermo King 098916, Maintenance Manual

Page: 49 / 196

Operating Instructions
48
• Voltage measuring circuits
Output signals from the controller automatically
regulate all unit functions including:
• Compressor operation
• Condenser fan operation
• Evaporator fan motor operation
• Compressor unload valve
• Vapor injection valve
• Dehumidify valve
• Electric heaters
• Phase selection
Change the Setpoint
To change the controller setpoint, turn
the
U
NIT
O
N
/O
FF
switch
O
N
. Complete
the following steps:
1. Press the
S
ETPOINT
key. The Setpoint menu
appears with the cursor in the [TEMP SETP]
line.
2. Press the
F4
key. An Enter Arrow appears in
the menu line and the current setpoint
disappears.
3. Enter (type) the new setpoint in the LCD
display using the general purpose keypad.
Press the
E
XIT
( ± ) key first to enter a minus
setpoint. The cursor moves to the right of the
screen as each key entry is acknowledged and
displayed.
NOTE: Always check that the setpoint
entered in the LCD display is correct before
proceeding.
4. Press and hold the
F4
key until the cursor
stops flashing. The new setpoint is recorded in
the controller and appears in the LCD display.
NOTE: The controller will default (return) to
the previous setpoint if the setpoint is not
entered within 30 seconds. Repeat steps 1
through 4 if this occurs.
NOTE: Humidity control, humidity setpoint and
Economy mode can also be set from the Setpoint
menu. See “Setpoint Menu” under “Menu
Operating Instructions” in this chapter.
Initiating a Manual
Defrost
Turn the U
NIT
O
N
/O
FF
switch O
N
. Complete the
following steps:
1. Press the D
EFROST
key.
• If the unit operating conditions allow a
manual defrost (e.g. evaporator coil
temperature is less than 18 C [56 F]), the
unit enters Defrost as the Defrost and Heat
LEDs turn on. LCD message display
shows [DEFROST ACTIVATED].
• If unit operating conditions do not allow
defrost, the LCD message display shows
[DEFROST NOT ACTIVATED].
2. The defrost cycle automatically terminates.
NOTE: A “timed” defrost of the evaporator
coil can be performed if frost or ice can not
be removed from the evaporator coil by an
automatic defrost cycle:
• Activate [HEAT ON] in the Manual Function
Test submenu.
• Press the
5
key six times. Heaters will be
activated for 70 minutes. Unit then returns to
normal operation.
Display Alternate
Controlling (Supply or
Return) Air Sensor
Temperature
The controller can show either the supply or
return air temperature in the LED Display. Turn
U
NIT
O
N
/O
FF
switch
O
N
. Complete the following
steps to display alternate controlling temperature:
1. Check the indicator LEDs to determine which
sensor temperature (supply air or return air)
currently appears in the right display. This is
the controlling sensor.
2. To view the alternate (supply or return) air
temperature, press and hold the S
UP
/R
ET
key.
The controller will show the alternate sensor
temperature as long as the
S
UP
/R
ET
key is
depressed.