Carrier VECTOR 1800 MT, Руководство по эксплуатации и обслуживанию

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62-11039 4-7
4.4.8 SPEED CONTROL
The engine will operate the compressor at two different
speeds (low and high). Speed Control will use the
differences of Controlling Temperature and setpoint as
follows:
Mode HIGH SPEED (SCS ENERGIZED) LOW SPEED (SCS DE--ENERGIZED)
COOL
(Perishable)
Return Air Temp is more than 2.7
°
F (1.5
°
C)
above setpoint
Return Air Temp is less than 2.3
°
F (1.3
°
C)
above setpoint.
COOL
(Frozen)
Return Air Temp is more than 3.6
°
F (2.0
°
C)
above setpoint
Return Air Temp is less than 1.8
_
F (1.0
_
C)
below setpoint
HEAT
(Perishable)
Return Air Temp is more than 2.7
°
F (1.5
°
C)
above setpoint
Return Air Temp is less than 2.3
°
F (1.3
°
C)
above setpoint.
HEAT
(Frozen)
Low Speed Only
NULL Low Speed Only
NOTE
The compartment furthest away from setpoint is used to determine speed. This compartment will fluctu-
ate depending on other control conditions.
4.4.9 DEFAULT MODE
When both the RAT and SAT alarms are on for
Compartment 1, or the RAT alarm is on for either
Compartment 2 or 3, the temperature control for that
compartment will go to default mode.
For compartments where the setpoint is in the
perishable range [+10.5
_
F (--12.1
_
C) or higher] or
higher), the LSV, heaters and fan motors will be turned
off for that compartment.
For compartments where the setpoint is in the frozen
range [+10.4
_
F (--12
_
C) or lower] or lower, the
compartment will operate in cool, and will only require
low speed. If the unit is operating on engine/road, the
compressor will fully unload (2--cylinder operation). If
the unit is operating on electric standby, the compressor
will be fully loaded (6--cylinder operation). (The engine
may still operate in high speed if another compartment is
calling for high speed.)
4.4.10DEFROST OPERATION
Defrost is an independent cycle overriding cooling and
heating functions in order to de-ice the evaporators as
required. When the unit is in defrost, the DEFROST LED
will be on, the MessageCenter will display DEFROST
CYCLE STARTED for 5 seconds. The center of the Main
Display will show “dF”. The CSMV will close in the defrost
cycle.
TIP
Ice is not the only thing that will cause the air dif-
ferential to increase across the evaporator coil.
Shrink wrap, paper, plastic bags, and other
such items when caught in the return air stream
and pulled up against the evaporator coil or the
return air grille can also cause the DAS contacts
to close.
NOTE
The unit will operate in high speed in the de-
frost mode.
1) Defrost Modes
There are two different Defrost Modes available:
S
Return Air Defrost Mode does not use electric heat-
ers, but uses the heat from the product to melt any
ice. Return Air Defrost is ONLY available when the
unit is being operated with Compartment 1 only, AND
when the RAT is 35.6
_
F (2
_
C) or higher, AND the SAT
is 39.2
_
F (4
_
C) or higher. Defrost will be accom-
plished by turning off the compressor and the refrig-
eration system, and allowing the evaporator fans to
operate. Blowing compartment air over the evapora-
tor coil will melt the ice and prevent heat from entering
the compartment from the heaters.
S
Normal (Electric) defrost mode can be started when
the DTT in any compartment is below 40
_
F (4.4
_
C).
When Defrost is called for, all active compartments
will stop normal cooling (or heating) and defrost at the
same time. Compartments where the DTT is above
40
_
F (4.4
_
C) will turn off and remain off until all other
compartments have completed defrost.
NOTE
NOTE: For both 2 and 3 compartment units:
During defrost, if the RAT for any enabled
compartment goes above 95
_
F (35
_
C), or if the
SAT in Compartment 1 is above 113
_
F (45
_
C),
all of the electric heaters will de--energized, and
wait until the RAT temperature drops below
89.6
_
F (32
_
C), or the SAT temperature drops
below 107.6
_
F (42
_
C). This is an overheat
protection feature.
a. For 2 compartment units, when both
evaporators require defrost, HTCON1 and HTCON2 will
be energized for Compartment 1, and 2HTCON1 and
2HTCON2 will be energized for Compartment 2. When
the DTT for any compartment reaches 55
_
F (12.8
_
C),
that compartment will stop defrost by de--energizing
HTCON1 & 2 for that compartment, and waiting for the
remaining compartment to complete defrost.
b. For 3 compartment units, 1/2/3HTCON1
heaters may be used at the same time, but only 2 of the
HTCON2 heaters may be used. (There are a total of 6
HTCONs in a 3--compartment unit – HTCON1 and
HTCON2 for each compartment. A maximum of 5