Electrical; Electronic Thermostat Installation - Bosch LM024 Installation, Operation And Maintenance Manual

LM Series Heat Pump
The return air inlet to the heat pump must have at
least one 90 degree turn away from the space
return air grille. If air noise or excessive air flow are
a problem, the blower speed can be changed to a
lower speed to reduce air flow. (Refer to ECM
motor interface board section in this manual and
Figure #8)

ELECTRICAL

Field wiring must comply with local and national
electric codes. Power to the unit must be within
the operating voltage range indicated on the unit
nameplate or on the performance data sheet. .
CAUTION: Operation of unit on improper
line voltage or with excessive phase
imbalance will be hazardous to the unit,
constitutes abuse and may void the
warranty.
Properly sized fuses or HACR circuit breakers must
be installed for branch circuit protection. See unit
nameplate for maximum fuse or breaker size.
Figure # 7 Electrical Component Box Layout
The unit is provided with a concentric knock-out in
the front left corner post for attaching common
trade sizes of conduit, route power supply wiring
through this opening. Always connect the ground
lead to the grounding lug provided in the control
box and power leads to the power supply terminal
block as indicated on the wiring diagram and
Figure #7.
Revised 01-14
ECM Interface Board
Figure # 8

Electronic Thermostat Installation

Position the thermostat subbase against the wall
so that it is level and the thermostat wires
protrude through the middle of the subbase. Mark
the position of the subbase mounting holes and
drill holes with a 3/16-inch bit. Install supplied
anchors and secure base to the wall. Thermostat
wire must be 8-conductor, 18-AWG wire. Strip the
wires back 1/4-inch (longer strip lengths may
cause shorts) and insert the thermostat wires into
the connector as shown. Tighten the screws to
ensure secure connections. The thermostat has
the same type connectors, requiring the same
wiring. See instructions in the thermostat for
detailed installation and operation information.
When using a 2-cool, 3-heat thermostat both the
W1 & W2 on the Heat Pump and W2 & EM on
the thermostat must be connected together via
a jumper. (See Figure#9)
THERMOSTAT
R
G
Y1
Y2
C
O
B
E
W2
Figure # 9
ELECTRICAL | 7
PACKAGED
HEAT PUMP
R
G
Y1
Y2
C
O
B
W1
W2
8 733 920 847 (2014/01)