Electrical - Low Voltage - Bosch LV Series Installation And Maintenance Manual

10 | Installation
For heat pumps with unit mounted disconnect
switches, field power should be connected to the
marked terminals on the disconnect switch. For
heat pumps without unit mounted disconnect
switches (except for 460 volt units noted below
and units with dual power supply), power is
connected to the line (L) side of the compressor
contactor and the ground lug in the unit electrical
box.
Models with Dual Power Supplies
For models with dual power supplies, one power
supply feeds the compressor and a second power
supply feeds the unit fan motor and control circuit.
The compressor power supply should be
connected to the line (L) side of the compressor
contactor. The fan motor and control circuit
power supply should be connected to a provided
terminal block. Care should be taken to insure that
each power supply meets the voltage, amperage
and phase requirements of its load. Refer to the
unit nameplates for requirements.
460 V Models with Constant Air Flow Motors
(LV015-LV070)
460 volt LV heat pumps with the constant airflow
motor option require a properly sized neutral wire
with the power supply wiring in addition to the
three high voltage wires and the ground wire.
These units employ a 265 V motor that requires
power from one phase of the 460 V supply and the
neutral wire.
The power supply ground wire should never
be used as a neutral wire.
For 460 V models with constant air flow motors
and a unit mounted disconnect switch, the power
wires and neutral wire should be connected to the
appropriate terminals on the disconnect switch
and its enclosure. For units without a disconnect
switch, power and neutral wires should be
connected to a provided 4 pole terminal block in
the unit electrical box
Transformer Settings for 208/230 V Units
As factory built, all 208/230 V units are wired for
230 V operation unless the wire for 208 V option is
ordered. For jobsites with a 208 V power supply,
the primary leads on the unit transformer will need
to be changed from 240 V to 208 V. Refer to the
unit wiring diagram for details.
8 733 905 683 (2013/04)

Electrical - Low Voltage

For heat pumps with PSC or constant torque fan
motors, all thermostat wiring is connected to a
terminal block located in the unit electrical box.
For heat pumps with a constant air flow fan motor,
thermostat wiring is connected to a removable
terminal strip located on the ECM motor control
board located in the electrical box. Refer to the
unit wiring diagram for connection details.
Never route control wiring through the same
conduit as power supply wiring.
Unless provided with DDC controls, the LV heat
pump can be controlled by most commonly
available single stage heat pump thermostats.
Note that the reversing valve on the LV series is
energized when the unit is in the cooling mode.
Thermostats should be located on an interior wall
away from supply ducts. Avoid locations subject to
direct sunlight or drafts, or external walls.
Thermostat wiring should be 18 AWG. Refer to the
installation instructions for the thermostat for
further details.
Exceptionally long runs of thermostat wire
should be avoided to prevent voltage drops in
the control circuit.
LV heat pumps are supplied with a 50 VA control
transformer as standard. Models with DDC, hot
gas reheat or an economizer are supplied with a 75
VA transformer. 75 VA and 100 VA transformers
are available as optional components for most
models (size 018 and larger for 100 VA). The VA
capacity of the transformer should be considered
when connecting low voltage accessories to the
heat pump such as thermostats or solenoid valves.
Table #2 shows the VA draw of factory mounted
components in the LV heat pump. The total VA
draw of the heat pump internal components plus
any attached accessories must be lower than the
VA capacity of the unit control transformer.
Exceeding the transformer capacity can
result in low control voltage, erratic unit
operation or damage to the heat pump.
Subject to change without prior notice
LV Heat PumpSeries
LV Heat Pump Series