Carrier 69NT40-541-300, Операция и обслуживание, Страница: 122 / 152

6 − 34 T − 318
6.30 COMMUNICATIONS INTERFACE MODULE
INSTALLATION
Communications
interface Module
CB1
Figure 6-36 Communications Interface Installation
Units with communication interface module provision
have the required wiring installed. The provision wiring
kit (part number 76-00685-00), includes three
pre-addressed wires installed between the circuit
breaker and communication interface module locations.
These wires are to be connected to the module and
circuit breaker to allow the module to communicate over
the power system. To install the module, do the
following:
WARNING
The unit power plug must be disconnected
to remove power from circuit breaker CB1
a. CB1 is connected to the power system, see wiring
schematic. Ensure that the unit power is off AND that
the unit power plug is disconnected.
b. Open control box, see Figure 6-36 and remove low
voltage shield. Open high voltage shield.
c. Remove the circuit breaker panel, with circuit break-
er, from the control box.
d. Locate wires CB21/CIA3, CB22/CIA5 and
CB23/CIA7 that have been tied back in the wire har-
ness. Remove the protective heat shrink from the
ends of the wires.
e. Attach the three wires as addressed to the LOAD side
of the circuit breaker.
f. Refit the circuit breaker panel.
g. Fit the new RMU into the unit.
h. Remove plugs CIA, CIB and CID from the wiring har-
ness and attach to the module.
i. Replace the low voltage shield.
6.31 POWER FACTOR CORRECTOR
CAPACITORS (PFC)
The power factor corrector capacitors are of the
permanent-split capacitor type. There are a total of
three capacitors with discharge resistors enclosed in a
single case.
a. When to check for a defective capacitor
The capacitors assist in correcting current draw by the
compressor. If one or more of the capacitors is faulty,
there will be an imbalance in current. In addition, the
power consumption of the unit will increase.
b. Removing the capacitor
WARNING
Make sure power to the unit is OFF and
power plug disconnected before removing
capacitor(s).
WARNING
Before removing the capacitors the
terminals must be checked for voltage with
a multimeter. The discharge resistors
installed on the unit (capacitors) should
bring the voltage to a safe level in a minute.
However, there may be a broken resistor
that retains voltage for a longer period, it is
highly recommended to wait 15 minutes
and to check for voltage.
If the capacitors require discharging, first, turn the unit
power OFF and disconnect the unit power plug. Then,
place a 20,000 ohm, 2 watt resistor across the terminals
of the capacitor for approximately 30 seconds.
1. The capacitors are located on the unit sidewall
above the evaporator fan deck and may be removed
by two methods:
If container is empty − Open upper rear panel of
the unit. The capacitors will be on the right and
may be serviced after checking discharge.
If container is full − Remove the upper fresh air
makeup vent.
c. Checking the capacitor
If the capacitor is suspected of malfunction, you may
choose to simply replace it. Direct replacement requires
a capacitor of the same value. Two methods for
checking capacitor function are: