Carrier TRANSICOLD Vector 8500 Operation & Service Manual Download

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4–14

4.11 PREPROGRAMMED SOFTWARE OVER-

RIDES

4.11.1

High Discharge Temperature

The control system monitors the signal provided by the
compressor discharge temperature sensor. If compres-
sor temperature rises to the limit, the system will enter
Liquid Injection Mode. In this mode the normally closed
liquid injection valve (LIV) will be opened to allow flow
of refrigerant into the economizer connection to cool
the compressor.

4.11.2

Cargo Protect Mode

The control system will activate Cargo Protect Mode
when the A00122 - “CHECK RETURN AIR SENSOR”
and A00123 - “CHECK SUPPLY AIR SENSOR” alarms
activate at the same time.

• If the setpoint is in the perishable range (refer to

Section 4.7.1

), the unit will shutdown.

• If the setpoint is in the Frozen Range the engine

will go to low speed.

The MessageCenter will display “WARNING: NO TEM-
PERATURE CONTROL” when the unit is operating in
Cargo Protect Mode.

4.11.3

Engine Speed Overrides

This section lists the different factors that determine
engine speed (high or low) in addition to the speed
controls used in temperature control.
Speed Control Overrides in priority order are:
1. High Voltage

If the 20 second average voltage is greater than
585V or the instantaneous voltage is greater
than 595V, force low speed for 10 minutes.

2. RAT & SAT Alarms

When the A00122 - “CHECK RETURN AIR
SENSOR” and A00123 - “CHECK SUPPLY

AIR SENSOR” alarms are both active at the

same time the control system will enter Cargo
Protect Mode. Refer to

Section 4.11.2

3. Engine Coolant Warm-Up

The engine will run in low speed until the cool-
ant is above 79°F (26°C).

4. Door/Remote Switch Configuration

If the DOOR/REMOTE SWITCH Configuration
is set for low speed, the engine will run in low
speed when the door/remote switch is open/
active.

5. Automatic Silent Mode

If in diesel start/stop mode and engine restarts
for any reason except S/S Perish Override
Temp or S/S Frozen Override Temp (refer to

Table 3–2

), Diesel Engine Mode is forced to

low speed for the minimum OFF time. If any
time during the override the unit is no longer in
Diesel start/stop mode, disable the override
until the next restart. This Override does NOT
apply for the first start of the engine.

6. Adjustable High Speed Delay

Whenever the engine starts, the unit will
remain in low speed according to the Continu-
ous or Start-Stop High Speed Delay Functional
Parameter setting.

High Speed Delay
Whenever the engine is in low speed, transi-
tion to high speed will be delayed for the HIGH
SPEED DELAY Configuration setting.

Start-Stop Frozen Range
When in Start-Stop Operation with a setpoint in
the frozen range after the minimum run time
has expired, the engine will be forced to high
speed if the refrigerated compartment tem-
perature is not yet down to setpoint.

9. Frozen Setpoint Override

If the setpoint is in the frozen range and the
temperature is below setpoint, the engine will
operate in low speed.

10. Low Suction Pressure Override

If suction pressure is below

−

4 psig (

−

.27 bar)

for > 20 seconds , inhibit high speed operation.
Remain in low speed for 5 minutes and until
the suction pressure >

−

3 psig (

−

.2 bar).

11. Perishable S/S High Speed Override

With the system running in Start

−

Stop Run,

Perishable Mode, the safety conditions and
minimum on time are met, but the temperature
condition is not met, run in high speed. Remain
in high speed until the engine shuts off or the
safety conditions are no longer met.

12. High Speed Pulldown

For perishable continuous run mode, if High
Speed Pulldown is active, remain in high speed
until termination conditions have been met.

13. Product Shield High Air

The engine is forced to high speed if the
PRODUCT SHIELD HIGH AIR Configuration is
active, refer to

Section 4.10.3

14. Range Protect

When the unit is operating in Range Protect
and the compartment temperature is inside the
protected range, while all other conditions to
allow an off cycle are not met the engine will
operate in low speed.