Instruction manual

24 McQuay OM 920
Keypad/Display Menu Structure
Min OA Damper Menu
Min OA Pos is a status only item which indicates the current minimum position of the
outdoor damper. This value does not go above a value called the Ventilation Limit and does
not go below a value called the Demand Control Ventilation Limit.
On CAV units the Ventilation Limit and the Demand Control Ventilation Limit are fixed
values set equal to the Vent Limit= and DCV Limit= parameters. On VAV units the OA
Damper Position increases from the Vent Limit= value to the LoFloVent Limit= value as the
VFD speed goes from 100% down to the Min Clg Spd= value. The Demand Control
Ventilation Limit in this VAV case is determined by the Ventilation Limit X DVC Limit=/Vent
Limit=. When the Min OA Reset= parameter is set to “None” the Min OA Pos= value is set to
the Ventilation Limit. If Min OA Reset= is set to Network, Ext VDC, Ext mA, IAQ VDC, or
IAQ mA, the Min OA Pos= varies between the Ventilation Limit and the Demand Control
Ventilation Limit as the reset signal varies from its maximum to minimum value.
Vent Li mit is an adjustable item that sets the value of the Ventilation Limit on a CAV unit or
when a VAV unit is at 100% discharge fan speed.
DCV Limit is an adjustable item that sets the value of the Demand Control Ventilation Limit
on a CAV unit or when a VAV unit is at 100% discharge fan speed. This item is only used
when the “Min OA Reset=” is set to something other than “None.”
Table 14: Min OA Damper Menu
Menu Display Name Item Display Name Default Setting Range Password Level
Min OA Damper Min OA Pos= - 0-100% 6
Vent Limit= 20% 0-100% 6
DCV Limit= 10% 0-100% 6
Min OA Reset= None None 6
Network
Ext VDC
Ext mA
IAQ VDC
IAQ mA
DesignFlow= Yes No 6
Yes
OA @ MinV/mA= 0% 0-100% 6
OA @ MaxV/mA= 100% 0-100% 6
Min V/mA= 0.0/ 0.0-20.0/ 6
V V
mA
Max V/mA= 10.0/ 0.0-20.0/ 6
V V
mA
PPM @DCV Lmt= 800ppm 0-5000ppm 6
PPM @Vnt Lmt= 1000ppm 0-5000ppm 6
PPM= - 0-5000ppm 6
Min PPM= 0ppm 0-5000ppm 6
Max PPM= 2000ppm 0-5000ppm 6
V/A @Min PPM= 0.0/ 0.0-20.0/ 6
V V
mA
V/A @Max PPM= 10.0/ 0.0-20.0/ 6
V V
mA
Min Fan Diff= 20% 0-100% 6
Max Fan Diff= 50% 0-100% 6
OA Flow= - 0-60000CFM 6
MinOAFlw Spt= 2000CFM 0-60000CFM 6
Min Clg Spd= 40% 0-100% 6
LoFlo V Lmt= 30% 0-100% 6