Figure 43 Economizer Setup - Dry Bulb Control; Figure 44 Economizer Setup - Temphum Control; Figure 45 Economizer Setup - Enthalpy Control - Bard MEGA-TEC W090A Service Instructions Manual

chosen: Dry Bulb (Figure 43), TempHum (Figure
44) or Enthalpy (Figure 45). The following menu
shows the Enthalpy content which also contains
parameters that would be shown on Dry Bulb
(temperature only) and TempHum (temperature
and humidity only).
18. Press ENTER key to scroll to OA Temp Set (on
Drybulb Control and Temp/Hum Control A3
screens, this parameter will be titled Outdoor Set).
19. Press UP or DOWN keys to change the temperature
setpoint to desired value.
20. Press ENTER key to save the value and scroll to
Off Diff.
21. Press UP or DOWN keys to adjust the outdoor
temperature differential for which the economizer
is re-enabled.
22. Press ENTER key to save the value and scroll to OA
Hum Set.
23. Press UP or DOWN keys to adjust the humidity
setpoint to desired value.
24. Press ENTER key to save the value and scroll to On
Diff.
25. Press UP or DOWN keys to adjust the outdoor
humidity differential for which the economizer is
re-enabled.
26. Press ENTER key to save the value and scroll to
Dew Pt. Set.
27. Press UP or DOWN keys to adjust the outdoor dew
point setpoint for economizer operation to the
desired value.
28. Press ENTER key to save the value and scroll to On
Diff.
29. Press UP or DOWN keys to adjust the dew point
differential for which the economizer is re-enabled.
30. Press ENTER key to save the value.
31. Press ESCAPE key several times to return to Main
Menu screen.
See Table 10 for default settings for economizer
operation.
Mode Consideration
Temperature
Humidity
Dew Point
* In Enthalpy mode, outdoor temperature, humidity and calculated dew point are all considered for economizer operation.
TABLE 10
Economizer Default Settings
Economizer Available for Cooling
When the outdoor air temperature
is below 70°F
When the outdoor humidity is below
80%
When the outdoor dew point
is below 55°F
FIGURE 43
Economizer Setup – Dry Bulb Control
FIGURE 44
Economizer Setup – Temp/Hum Control
FIGURE 45
Economizer Setup – Enthalpy Control
Economizer Not Available for Cooling
When the outdoor air temperature
is above 75°F
When the outdoor humidity is above
80%
When the outdoor dew point
is above 60°F
Manual 2100-671C
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