5
ELECTRICAL
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury
or death.
Exercise extreme caution when working on any electrical
components. Shut off all power to system prior to
troubleshooting. Some troubleshooting techniques require
power to remain on. In these instances, exercise extreme
caution to avoid danger of electrical shock. ONLY TRAINED
SERVICE
PERSONNEL
SHOULD
PERFORM
ELECTRICAL TROUBLESHOOTING.
!
WARNING
Aluminum Wire
UNIT OPERATION AND SAFETY HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
Aluminum wire may be used in the branch circuit (such as
the circuit between the main and unit disconnect), but only
copper wire may be used between the unit disconnect and the
unit.
CAUTION
!
Whenever aluminum wire is used in branch circuit wiring with this
unit, adhere to the following recommendations.
Connections must be made in accordance with the National
Electrical Code (NEC), using connectors approved for aluminum
wire. The connectors must be UL approved (marked Al/Cu with
the UL symbol) for the application and wire size. The wire size
selected must have a current capacity not less than that of the
copper wire specified, and must not create a voltage drop between
service panel and unit in excess of 2 of unit rated voltage. To
prepare wire before installing connector, all aluminum wire must
be “brush--scratched” and coated with a corrosion inhibitor such as
Pentrox A. When it is suspected that connection will be exposed to
moisture, it is very important to cover entire connection completely
to prevent an electrochemical action that will cause connection to
fail very quickly. Do not reduce effective size of wire, such as
cutting off strands so that wire will fit a connector. Proper size
connectors should be used. Check all factory and field electrical
connections for tightness. This should also be done after unit has
reached operating temperatures, especially if aluminum conductors
are used.
Unit Electrical Power
Power wires from the unit’s disconnect should be routed through
the power wiring hole provided at the bottom of the unit’s control
box.
Connect the ground wire to the ground connection in the control
box and connect the power wiring to the terminal block as shown
on the wiring and Installation Instructions supplied with the unit.
The unit does not require a contactor or outdoor unit transformer in
order to operate.
MAJOR COMPONENTS
Application Operational Control Board (AOC)
A13361
Fig. 1 – AOC (Application Operational Control) Board
The AOC board is located in the lower right hand side of inverter
tray. It’s functions include:
S
Compressor speed control
S
Outdoor fan motor control
S
Reversing valve operation
S
Defrost operation
S
Crankcase heater operation
S
Pressure switch monitoring
S
Time Delays
S
Pressure Transducer measurements
S
PEV control (pressure equalizer valve)
S
Temperature measurements
S
EXV (Electronic Expansion Valve) operation control
S
Inverter communication and control
Inverter
The inverter is located inside the control box. This is an air--cooled
device that communicates with the control board and drives the
compressor and fan motor to the demanded RPM. The inverter is
always powered with line voltage since no contactor is used. The
inverter changes the line voltage to DC volts and then recreates 3
phase sine waves that vary in frequency to drive the compressor
and fan motor at the desired RPM.
NOTE
: The unit may be operated with an Evolution Connex
Control or a standard 2--stage HP thermostat. However, 1--ton
models will require the use of an Evolution Control. Evolution
Connex Control will utilize 5 stages of heating and cooling, while
2--stage HP thermostat will only allow 2 discrete stages of heating
and cooling operation.
Variable Speed Compressor
This unit contains a variable speed rotary compressor that has a
wide operating range. It operates on a variable 3 phase sine wave
provided by the inverter. This compressor can only be operated by
the specific inverter supplied with the unit.
Содержание 189BNV EVOLUTION
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