Carrier 48PG03-16 Controls, Start-Up, Operation, Service And Troubleshooting Instructions page 63

DISPLAY KEYPAD
MENU ENTRY
ENTER
ENTER
ENTER
SETPOINTS SETPOINTS
B
ENTER
ESCAPE
T.CTL = 1 (1 Stage Y1)
When T.CTL = 1, no additional compressor staging timers or
supply air temperature limits apply. Compressor staging will
follow the thermostat inputs directly. Y1 will turn on refrigerant
circuit A. Y2 will add the remaining refrigerant circuits, B for
sizes 08-14, or B and C for size 16. Compressor minimum
on-time (MRT.C) and compressor minimum off-time (MOT.C)
do apply.
T.CTL = 2 (2 Stage Y1) 48/50PG16 Only
When T.CTL = 2, no additional compressor staging timers or
supply air temperature limits apply. Compressor staging will
follow the thermostat inputs directly. Y1 will turn on refrigerant
circuit A and B. Y2 will add the remaining refrigerant circuit C.
Compressor minimum on-time (MRT.C) and compressor
minimum off-time (MOT.C) do apply.
T.CTL = 3 (Digital) 4050PG16 Only
When T. CTL = 3, no additional compressor staging timers or
supply air temperature limits apply. Compressor staging will
follow the thermostat inputs directly. Y1 only will turn on
refrigerant circuit A. Y2 only will turn on refrigerant circuits A
and B. Y1 and Y2 will turn on refrigerant circuits A, B, and C.
Space Sensor Control
To operate the unit in Space Sensor mode, set the Unit Control
Type to 3 (Configuration→UNIT→U.CTL=3). To enable
heating during space temperature control, a jumper wire must be
added between R and W1 on the field connection terminal strip
(see Major System Components section for wiring diagrams).
Because Space Sensor mode is an "Auto" mode, the control will
switch between cooling and heating to maintain space
temperature. However, to minimize unnecessary changes, there is
a 10-minute mode select timeguard (Operating Modes→
COOL→MS.TG), after the last stage of heat turns off before
cooling is allowed.
The unit tries to maintain the space temperature at the Occupied
Cool Set Point (Setpoints→OCSP) or the Unoccupied Cool Set
Point (Setpoints→UCSP). See the Occupancy Determination
section for factors that affect the Occupied status (Run
Status→VIEW→OCC). The Cooling Demand (Operating
Modes→COOL→SPT→DMD.C)
Temperature (Operating Modes→COOL→SPT→SPT) minus
the occupied or unoccupied set point (DMD.C = SPT – set point).
See Table 87 for an example of reading and changing the
occupied set point (OCSP).
Two methods are used to add and remove stages of cooling for
units with more than one compressor. The first method causes the
unit to operate around its steady-state number of stages. For
example, if the correct number of stages is between 0 and 1, this
method will cause the first stage to cycle. If the correct number of
stages is between 1 and 2, this method will cause the second stage
to cycle. The second method causes the unit to find the
steady-state number of stages. Details of these methods are
provided below.
Table 87—Reading and Changing Cooling Occupied Set Point
ITEM DISPLAY
OCSP 78
78
78
75
OCSP 75
is equal to Space
ITEM EXPANSION
Occupied Cool Set point
Occupied Cool Set point
The control uses two methods to add a stage of compressor
cooling. The first method will add a stage of cooling when the
Cooling Demand (Operating Modes→COOL→SPT→ DMD.C)
plus the change
Modes→COOL→SPT→TRD.C) times the Cool Thermal Lag
Factor (Operating Modes→COOL→SPT→C.LAG) is greater
than the SPT Cool
Modes→COOL→SPT→CL.PD).
DMD.C + TRD.C * C.LAG > CL.PD
This method is only used after the Compressor Settling Time
(Configuration→UNIT→SAT.T), has been exceeded and the
supply-air temperature is slowly increasing. The second method
will add a stage of cooling when Cool Demand is greater than the
SPT Cool Demand (+) Level plus 0.5° F (DMD.C > CL.PD +
0.5) and the
Modes→COOL→SAT→SAT) is changing at a rate greater than
–0.3° F per minute.
The control uses two methods to remove a stage of compressor
cooling. The first method will remove a stage of cooling when
the Cooling Demand
→SPT→DMD.C) plus the change in cool demand (Operating
Modes→COOL→SPT→TRD.C) times the Cool Thermal Lag
Factor (Operating Modes→COOL→SPT→C.LAG) is less than
the SPT Cool
Modes→COOL→SPT→CL.ND).
DMD.C + TRD.C * C.LAG < CL.ND
This method is only used after the Compressor Settling Time
(SAT.T), has been exceeded and the supply air temperature is
slowly decreasing. The second method will remove a stage of
cooling when Cool Demand is less than the SPT Cool Demand
(–) Level minus 0.5° F (DMD.C < CL.ND – 0.5) and the supply
air temperature (SAT) is changing at a rate less than 0.2° F per
minute.
Configurable delays
(Configuration→COOL→C.INC)
(Configuration→COOL→C.DEC).
on-time (Configuration→COOL→MRT.C)
off-time (Configuration→COOL→MOT.C) also apply.
Outdoor Fans
Each unit has a means for variable outdoor airflow to control
condenser pressure control within an acceptable range by
responding to varied operating modes and ambient temperatures.
This is implemented differently on different units using
multi-speed motors, multiple outdoor fans, or variable-speed
motor controllers.
NOTE: Factory default configurations account for these model
differences and should
configurations have been qualified over a large range of
conditions and are provided in case a field replacement of a
control board occurs and the settings need to be checked or
manually configured. Outdoor fan operation is further described
below to assist in troubleshooting.
63
COMMENT
Default: 78
Scrolling Stops
Value flashes
Select 75
Change accepted
Item/Value/Units scroll again
in cool demand
Demand (+) Level
supply-air temperature
Modes→COOL
(Operating
Demand (–) Level
also apply when adding
or removing
Compressor
and
not be changed. The
(Operating
(Operating
(Operating
(Operating
stages
stages
minimum
minimum
default