62-11640 4–2
• through fuse F11 for the light bar (LB) green
LED’s.
• through fuse F9, contacts HVB7−E and HVB1−E
to SP−55. From SP−55 power is supplied to the
contactor control boards (1CCB14+ and
2CCB−14+) for operation of the contactors.
• Potential power is also established through fuse
F10 for the AFAR coil & FHR coil, and through
fuse F8 for the fuel level sensor (FLS). During
operation the main microprocessor will complete
the potential circuits, by supplying ground, ener-
gizing or de−energize the required components.
4.3 ENGINE/ELECTRIC OPERATION
Engine or Electric Operation is chosen at the display
panel (Refer to Section 3.4).
With Electric Operation chosen, the Control System will
energize the condenser fan motors in order to deter-
mine the phase sequence of the incoming power. If
incoming power is not correct, the system will shut-
down and restart, energizing the other power supply
contactor (PSCON or PSCON2). If the phase
sequence is not corrected by this action, the A00074 -
“PHASE REVERSED” alarm will be activated and the
unit will shutdown.
Energizing a power supply contactor reverses its con-
tacts to allow power from the power plug while the
engine is shutdown and power from the generator is
locked out.
When Engine Operation is chosen the generator contac-
tor (GENCON) is energized. Energizing GENCON
reverses its contacts to allow the engine and generator
to operate while power from the power plug is locked out.
Once the power selection is made:
• the stepper valve module will open the compres-
sor suction modulating valve (CSMV), evapora-
tor expansion valve (EVXV) and economizer
expansion valve (ECXV), to equalize system
pressure, and then bring the valves to a prede-
termined position before the unit starts.
• the contactor control boards will energize the
compressor, condenser fan motors, evaporator
fan motor and/or electric heaters as required.
4.3.1 Soft Start (Bump Start)
On command to start the compressor the control sys-
tem will determine if there is a need to perform a Soft
Start. Soft Start is performed to clear refrigerant from
the compressor and/or return oil; Soft Start will be acti-
vated if:
• the compressor has been off for more than
twenty− four hours or
• the compressor has been off for more than two
hours and suction and discharge pressure are
within 10 psi (0.7 bar) or
• the compressor has been off for more than two
hours and suction pressure is above discharge
pressure
During Soft Start the control system will de−energize
the liquid injection valve (LIV), economizer expansion
valve (ECSV) and energize the buzzer for five sec-
onds. Then the compressor will operate for one second
on, followed by nine seconds off. The on/off sequence
may repeat up to four additional times.
Following Soft Start the compressor will transition to
steady state operation, and the evaporator fans will
start.
If Soft Start is not required, the buzzer will be energized
for five seconds the compressor will start and the evap-
orator fans will start.
NOTE
The unit will not restart for at least 30 sec-
onds following a shutdown.
4.4 ENGINE CONTROL
Engine control consists of engine start-up and speed
control.
Figure 4.1 Auto Start Sequence
PREHEAT
(If required)
FIRST
ATTEMPT
SECOND
AND
THIRD
ATTEMPTS
15 Seconds
STOP
3 to 10
Seconds
0 to 30
Seconds
PREHEAT
(If required)
ENGINE
RUNNING
(preheat)
CRANK
(with preheat)
5 SEC. BUZZER
5 SEC. BUZZER
0 - 180
Seconds
following start
0 to 30
Seconds
0 - 180
Seconds
following start
3 to 10
Seconds
ENGINE
RUNNING
(preheat)
CRANK
(with preheat)
To Next Page
Loading...
Need help?
General
