Instruction manual

McQuay OM 920 25
Keypad/Display Menu Structure
Min OA Reset is an adjustable item that sets the type of minimum OA damper position reset
to be used. When this is set to “None” the Min OA Pos= parameter is set to the Ventilation
Limit. When this is set to “Network,” “Ext VDC,” “Ext mA,” “IAQ VDC,” or “IAQ mA” then
the Min OA Pos= parameter varies from the Ventilation Limit down to the Demand Control
Ventilation Limit as the reset signal goes from its maximum to minimum value.
Design Flow is an adjustable item used to turn the optional DesignFlow outdoor airflow
measuring reset function on and off. This is one of several available methods of automatically
resetting the Min OA Pos parameter.
OA @ MinV/mA is is an adjustable item used when Min OA Reset is set to “Ext VDC” or
“Ext mA” to define at what percent of the field input signal the Min OA Pos is to be at the
Demand Control Ventilation Limit value.
OA @ MaxV/mA is an adjustable item used when Min OA Reset= is set to “Ext VDC” or
“Ext mA” to define at what percent of the field input signal the Min OA Pos= is to be at the
Ventilation Limit value.
Min V/mA is an adjustable item used to set the minimum value of the field input signal.
Max V/mA is an adjustable item used to set the maximum value of the field input signal.
PPM @ DCV Limit is an adjustable item used when Min OA Reset= is set to “IAQ VDC” or
“IAQ mA” to define at what PPM value the Min OA Pos= is to be at the Demand Control
Ventilation Limit value.
PPM @ Vent Limit is an adjustable item used when Min OA Reset= is set to “IAQ VDC” or
“IAQ mA” to define at what PPM value the Min OA Pos= is to be at the Ventilation Limit
value.
PPM is a status only item which indicates the current reading from the CO2 sensor.
Min PPM is an adjustable item that sets the minimum PPM value.
Max PPM is an adjustable item that sets the maximum PPM value.
V/mA @ Min PPM is an adjustable item that sets the minimum PPM value and the minimum
DC voltage or mA value of the CO2 sensor used when Min OA Reset= is set to “IAQ VDC”
or “IAQ mA.”
V/mA @ Max PPM is an adjustable item that sets the maximum PPM value and the
maximum DC voltage or mA value of the CO2 sensor used when Min OA Reset= is set to
“IAQ VDC” or “IAQ mA.”
Min Fan Diff is an adjustable item which sets a differential between the discharge and return
fan capacities above which the minimum allowable Min OA Position begins to be reset
upwards from the Demand Control Ventilation Limit toward the Ventilation Limit.
Max Fan Diff is an adjustable item which sets a differential between the discharge and return
fan capacities at which the minimum allowable Min OA Position is fully reset up to the
Ventilation Limit.
OA Flow is a status only item which indicates the current outdoor airflow based on an
optional OA airflow sensor input used when the unit is equipped the DesignFlow OA control
feature.
Min OAFlw Spt is an adjustable item that is used to set the minimum design flow CFM's
when the unit is equipped with the optional DesignFlow OA control feature.
Min Clg Spd is an adjustable item that sets the discharge fan speed on a VAV unit at which the
Ventilation Limit reaches the LoFloVent= value.
LoFlo Vent Limit is an adjustable item that sets the maximum value for the Ventilation Limit
on a VAV unit.