Manual 2100-670B
Page
29 of 33
Enthalpy
(see Figure 42) as compared to when
type is set to
TempHum
(see Figure 43). The
following menu shows the
Enthalpy
content
which also contains parameters that would be
shown on
TempHum
.
18. Press ENTER key to scroll to
OA Humid Set
(see
Figure 42).
19. Press UP or DOWN keys to change the humidity
setpoint to desired value.
20. Press ENTER key to save the value and scroll to
W/O LV Set
.
21. Press UP or DOWN keys to change the humidity
setpoint for stand alone mode to desired value.
22. Press ENTER key to save the value and scroll to
OA
Dew Pt Set
.
23. Press UP or DOWN keys to adjust the dew point
setpoint for economizer operation to the desired
value.
24. Press ENTER key to save the value and scroll to
Off Diff
.
25. Press UP or DOWN keys to adjust the differential
where dew point no longer allows economizer
operation.
26. Press ENTER key to save the value and scroll to
parameter
Delay
.
27. Press UP or DOWN keys to adjust the delay
before the dew point consideration will allow the
economizer to operate.
28. Press ENTER key to save the value.
29. Press ESCAPE key several times to return to Main
Menu screen.
See Table 9 for default settings for economizer
operation.
If the economizer is activated during a cooling call using
any of the previously mentioned modes, a 0-10v signal
will be sent to the actuator. The actuator will then open
and close the damper blades to maintain a mixed air
temperature of 55°F. When the mixed air temperature
increases the damper will open and when the mixed air
temperature decreases the damper will close.
The economizer may be disabled by the LV if the
system determines it needs to enter dehumidification
mode. More information about the dehumidification
sequence can be found on page 12 and in the latest
revision of LV1000 Service Instructions 2100-673.
In addition to dehum mode, the economizer may be
disabled for 30 minutes (adjustable) if the dust sensor
indicates the outdoor air is not acceptable for cooling.
After the time has expired and on a call for cooling, the
economizer will open again to sample the air. The unit
FIGURE 42
Economizer Setup – Enthalpy Control
FIGURE 43
Economizer Setup – TempHum Control
TABLE 9
Economizer Default Settings
* In Enthalpy mode, outdoor temperature, humidity and calculated dew point are all considered for economizer operation.
Mode
Consideration
Economizer Available for Cooling
Economizer Not Available for Cooling
Temp
Only
Temp & Humidity
Enthalpy*
Temperature
When the outdoor air temperature
is below 70°F
When the outdoor air temperature
is above 75°F
Humidity
LV Online
: When the outdoor humidity
is below 80%
LV Online
: When the outdoor humidity
is above 80%
LV Offline
: When the outdoor humidity
is below 60%
LV Offline
: When the outdoor humidity
is above 60%
Dew Point
When the outdoor dew point
is below 55°F
When the outdoor dew point
is above 60°F
