Operation; Starting, Stopping And Operating Instructions; Starting; Stopping - Carrier CAPRI-280 Operation And Service Manual

2.1 STARTING, STOPPING AND OPERATING
INSTRUCTIONS
2.1.1 HVAC Power to Controller
Before starting the system, electrical power must be
available from the bus power supply. The HVAC
controller receives power from two sources:
a. 24 vdc power for the microprocessor electronics
is supplied through the bus multiplex module.
b. 24 vdc, 125 amp, power from a fuse in the battery
compartment supplies power which controls
relays, clutch and unloader solenoids in the
compressor, evaporator
assemblies; this power is controlled by the HVAC
controller.
2.1.2

Starting

a. If the engine is not running, start the engine.
After the engine is started place the A/C switch
located on the dash in the on position. All system
controls will operate automatically in heating,
cooling or ventilating mode, as required.
2.1.3 Self-Test and Diagnostics
(Check for Errors and/or Alarms)
Self-test of the main controller electrical circuit is
automatically initiated when the system is first
powered up. If there is an error in the circuit, ER''x"
will be indicated by flashing the error code on both the
status and code LED's simultaneously. If a diagnostic
module is connected to the controller, the error code
can also be read on the display. If there are no errors
in the circuit, system will operate normally and flash
the status LED at a one second interval. During
normal operation, the controller monitors system
operating parameters for out of tolerance conditions.
If an out of tolerance condition occurs, ALARM will
be indicated through the code LED or on the
diagnostic tool display. If an alarm condition exists,
diagnostics can be manually initiated to isolate system
fault(s) by simultaneously pressing the up and down
keys continuously for five seconds to view more
T-283
SECTION 2

OPERATION

information. Refer to section 3 for definition of
system errors and alarms and general troubleshooting
procedures.
2.1.4
With the system operating, switching the AC switch to
the off position will stop the HVAC system operation
by removing power to the logic module.
2.2
After starting system operation, allow system to
stabilize for ten to fifteen minutes and check for the
following:
and condenser
a. Listen for abnormal noises in compressor or fan
motors.
b. Check compressor oil level. (Refer to section
4.12.2.)
c. Check refrigerant level. (Refer to section 4.7.1.)
d. Ensure that self-test has been successfully
performed and that there are no errors or alarms
indicated. (Refer to section 2.1.7.)
2.3
2.3.1
Temperature is controlled by maintaining the return
air temperature measured at the return air grille.
2.3.1.1
The controller automatically compares system
temperatures with the controller setpoints and
changes
temperature deviations. Figure 2-1 shows various
changes in operating modes and controller actions at
various temperature deviations from controller
setpoint. Upon rising temperature, mode changes
occur when temperatures are above those given in
Figure 2-1 above controller setpoints, On a falling
temperature,
temperatures are below those given in Figure 2-1. The
system will operate in these modes unless pressures
override the controller settings.
2-1

Stopping

PRE-TRIP INSPECTION

SYSTEM OPERATION

Temperature Control
Capacity Control
system operating modes
mode changes
at certain
occur when