User Manual

Mixing Box Control Installation Manual
IOM-MBC-00 08-30-04
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4.
Turn enthalpy set
potentiometer to “A”.
LED should be on,
indicating low enthalpy.
Motor drives toward
open.
5.
Turn enthalpy set point
potentiometer to “D”.
LED should be off,
indicating high enthalpy.
Motor spring returns to
fully closed position.
6.
Disconnect the 1.2k ohm
checkout resistor.
C. Sensor
1.
Reconnect the + lead of
outdoor enthalpy sensor
to the + terminal of
W7459.
2.
Connect a DC multi-meter
or voltmeter between
terminals S
O
of the W7459
and terminal S of the
enthalpy sensor. (Positive
meter lead to terminal S of
enthalpy sensor.)
Multi-meter or voltmeter
should indicate between
3 and 25 mA, if sensor
is operating properly.
If multi-meter or
voltmeter indicates
zero, the sensor may be
wired backwards.
3.
If using differential
enthalpy, the return air
enthalpy sensor may be
checked by connecting a
DC multi-meter or
voltmeter between
terminal S
R
of the W7459
and terminal S of the
return air enthalpy sensor.
(Position meter lead to
terminal S of return air
enthalpy sensor.
Multi-meter or voltmeter
should indicate between
3 and 25 mA, if sensor
is operating properly.
If multi-meter or
voltmeter indicates
zero, the sensor may be
wired backwards.