Daikin Maverick I Installation And Maintenance Manual page 75

User Interface
Economizer Status
This screen gives the status of the exhaust fan.
Enthalpy Setpoint
The user has five levels to choose for the enthalpy set point.
Figure 9 indicates what each of those levels represents in the
psychometric chart. This setting determines the level at which
economization is allowed. This setting is only adjustable at
economizer potentiometer.
Figure 9: Demand Control Ventilation
Effective Mixed Air Temperature
This is the current value of mixed air temperature.
Mixed Air Setpoint
When the mixed air temperature falls below this set point, the
freeze protection control will disable the mixed air control and
close the outdoor damper to the effective minimum position.
External Mixed Air Temperature
This screen corresponds to the discharge air temperature
reading from the DDC Controller.
Economizer Ventilation Limit
The ventilation limit corresponds to a minimum position of the
Economizer that complies with the minimum acceptable
outside-air ventilation rate. The volumetric flow-rate of
outside air required to provide healthful, comfortable
conditions for occupants can be determined from building
20
codes, ASHRAE standards, or standard practice. It is usually
expressed in terms of volumetric flow-rate (cfm) per occupant
or per unit floor area. The use of a CO2 sensor can lower the
ventilation limit by verifying that the indoor air quality is
suitable for human occupancy, as described in the next section
for Demand Control Ventilation (DCV).
The system allows the adjustment of the ventilation limit
through four different methods, listed below in order of
priority:
1 Network interface (BACnet, BAS, or LonWorks)
Human Systems Interface (HSI)
2
Remote potentiometer
3
Direct adjustment through a potentiometer on ELM
4
control.
Economizer Exhaust ON/OFF
This screen allows the user to change the set point of what
percentage the exhaust fan is energized.
Economizer DCV Limit
The economizer will allow the dampers to close more than the
minimum position if the indoor air quality is not contaminated.
The Econ. DCV Limit can be set from 0 to 100% but must be
lower than the minimum position.
Economizer DCV Control
If connected to a CO2 sensor, the ELM measures and regulates
the amount of outdoor air supplied to the space in order to
maintain the levels of carbon dioxide below the recommended
700ppm above the outdoor levels. In this case, CO2 levels
serve as a proxy for building occupancy and the rate of human-
generated indoor pollutants.
Once the DCV is operating, the minimum damper position can
then be lowered to the DCV ventilation limit. By default, this
value is 50% of the ventilation limit, but the user has the
option to adjust it through network or human system interface.
The user also has the option to disable DCV altogether.
DCV Level Setpoint
The DCV level setpt is a selectable level of carbon dioxide that
the system does not allow to be exceeded. The set point is
communicated to the economizer and the minimum ventilation
position is changed in order to prevent the increase of CO2.
External DCV Level
This is the value DDC Controller sends to the Economizer.
Effective DCV Level
This is the actual DCV Level in ppm.
Effective Economizer Position
This is the actual position of the economizer.
McQuay OM 1077