Bosch EP Series Installation And Maintenance Manual page 10

10 | Thermostat Connections
EM (Red) Emergency Heat On
W1 (Red Auxiliary Heat On
O (Green) Reversing Valve Energized, unit is
in Cooling Mode
Y2 Second Stage Compressor On
(Green)
Y1 First Stage Compressor On
(Green)
G (Green) Fan On
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
approximately 100 CFM of air delivery so if the LED
blinks 12 times, pauses, blinks 12 times, etc. the
blower is delivering approximately 1200 CFM. for
factory programmed air delivery settings for the EP
Series.
To the right of the thermostat connection block is
a green LED labeled dehumidify.
Just above and to the right of the thermostat
connection block are four sets of jumper pins
labeled ADJ, DELAY, HEAT and COOL. The ADJ set
of pins are labeled NORM, (+), (-) and TEST. EP
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.
8733953041 (2019/01)
NOTE: Do not set the ADJ DIP switch 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.
The other DIP switch bank is used to select the
proper program in the ECM motor for the unit.
Refer to Figure #7 for the proper jumper
placement.
WARNING: Always disconnect power
before changing jumper positions on the
interface board and reset the unit
afterward.
WARNING: Remember to always turn
off unit power at the circuit breaker
before attaching or disconnecting any
wiring from these connections to avoid
accidental short circuits that can
damage unit control components.
To the left of the red and green status LED's is a
row of 1/4" male quick connects. These are used
to pass thermostat inputs on to the rest of the
control circuit.
Subject to change without prior notice
EP Series
EP Series