Bosch SM SERIES - Installation and Connection

SM Split AH/AV Air Handler
SM Split AH/AV Air Handler8733826256 (2020/06)
14 | Electrical
Subject to change without prior notice
Bosch recommends the use of 18 AWG thermostat
conductive cable for up to 60 foot, 16 AWG up to
100 ft, and 14 AWG up to 140 ft. to wire from the
condensing section terminal strip to the air
handler terminal strip.
Connection point logic is as follows:
To the left of the thermostat connection block are
a row of 2 red and 4 green LEDs. These LEDs
indicate the operating status of the unit. (See Fig.
13.) They are labeled as follows:
Table 5 Connection Point Logic
Just above the connector block is a single-red LED
labeled CFM that will blink intermittently when the
unit is running and may flicker when the unit is off.
This LED indicates the air delivery of the blower at
any given time. Each blink of the LED represent
100 CFM of air delivery so if the LED blinks 12
times, pauses, blinks 12 times, etc. the blower is
delivering 1200 CFM. Refer to Table 6 for
factory-programmed air delivery settings for the
SM Series.
Motor Profile Air-Flow Table CFM
Table 6 Motor Profile Air-Flow Table CFM
Just above and to the right of the thermostat
connection block are DIP Switches labeled ADJ,
DELAY, HEAT and COOL. The ADJ set of pins are
labeled NORM, (+), (-) and TEST. SM units will all
be set on the NORM position from the factory,
however, airflow can be increased (+) or
decreased (-) by 15% from the pre-programmed
setting by relocating the jumper in this section.
The TEST position is used to verify proper motor
operation. If a motor problem is suspected, move
the ADJ jumper to the TEST position and energize
G on the thermostat connection block. If the motor
ramps up to 100% power, then the motor itself is
functioning normally. Always remember to replace
the jumper to NORM, (+) or (-) after testing and
reset the unit thermostat to restore normal
operation. (See Fig. 13.)
The other three sets of jumper pins are used to
Connection Color Operating Status
EM
RED Emergency Heat ON
W1
RED Auxiliary Heat ON
O
GREEN
Reversing Valve
Energized, unit is in
cooling mode
Y2
GREEN
Second-Stage
Compressor ON
Y1
GREEN
First-Stage
Compressor ON
G
GREEN Fan ON
To the right of the thermostat connection
block is a green LED labeled dehumidify. On
dehumidification call the fan will operate at
a lower speed to increase dehumidification
while cooling.
Motor Fan
Only
Y1
Cool/Heat
Y2
Cool/Heat
AUX
Heat
Emerg.
Heat
Plus
ADJ
Minus
ADJ
Tap Cool/
Heat/Delay
SM024
450 500 800 800 800 900 700 A
SM036
700 1050 1225 1225 1225 1400 1050 A
SM048
900 925 1500 1500 1500 1700 1275 B
SM060
1200 1500 2000 2000 2000 2300 1700 A
NOTICE: Do not set the ADJ jumper to the
(-) setting when electric heaters are
installed. Doing so may cause the heaters to
cycle on their thermal overload switches,
potentially shortening the life of the
switches.