Section 10 - W7340 and W7345 Economizer Module
99 Honeywell Economizers 63-8594-02
Settings and Adjustment
W7345
Potentiometers located on the face of the
W7345, provide adjustments for Minimum
Damper Position parameters (see below).
Location of W7345
potentiometers and LED
W7340
Using the DCV potentiometer, the setpoint can
be adjusted until three minutes after powering
the device. Through the Modbus, the DCV
setpoint can be modified at any time. If the
DCV potentiometer is changed after the three
minute power-up time, no change to the DCV
setpoint will occur unless power is removed
from the device then reapplied.
Location of W7340
potentiometers and LED
If the mixed air temperature drops to 45°F
(7°C), the mixed air sensor overrides the DCV
sensor and closes the damper to DCV
minimum position to protect the hot or chilled
water coils from freezing. When the mixed air
temperature rises to 48°F (9°C), control
reverts to normal operation.
Exhaust Setpoint (W7340 only)
The exhaust setpoint determines when the
exhaust fan will run based on the damper
position, this function is the same as the
exhaust setpoint on the W7215 and W7212
except, as shipped from the factory, the
W7340 uses an exhaust setpoint of 25%.
When the damper position is greater than 25%
open (from fully closed), the logic module calls
for exhaust. When the damper position is
below 22% open, the exhaust relay is de-
energized.
The W7340C has an E curve in addition to the
A, B, C and D curves. See the chart below
showing location of E curve on Psychrometric
chart.
PP1
MBUS-
MBUS+
TR1 24V COM
TR 24V AC
-
MIN POS/
DVC MAX
OPEN
C
B
E
A
STATUS LED
DRY BULB
CHANGEOVER
SETPOINT
MINIMUM
DAMPER
POSITION
M23877
D
MAT
OAT
RAT
PP1
+
-
+
-
ExF
MAT
OAH
OAT
RAT
RAH
DCV
2-10 VDC
DAMPER
POSITION
2-10 VDC
DAMPER
POSITION
OVERRIDE
MIN POS/
DCV MIN
OPEN
DCV
SETPOINT
1500500
STATUS LED
DEMAND
CONTROL
VENTILATION
SETPOINT
ENTHALPY
CHANGEOVER
SETPOINT
MIN POS/DCV
MIN DAMPER
POSITION
M23878
MBUS-
MBUS+
TR1 24V COM
TR 24V AC
C
B
E
A
D
+
_
+
_
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