Instruction manual

McQuay OM 920 35
Keypad/Display Menu Structure
Zone Temperature Setup Menu
Ctrl Temp Src is an adjustable item which selects the temperature sensor input to be used for
the unit heating/cooling changeover or zone cooling and heating capacity change decisions.
For example, if the CtrlTemp Src parameter is set to “Return,” then the Control Temp
parameter reads the same value as the Return Air parameter.
Use Tstat Spt is an adjustable item used to set whether to use the Tstat setpoint adjustment
value for the Zone Clg Spt and Zone Htg Spt.
Zone Clg DB is an adjustable item which sets a dead band around the Zone Cooling Setpoint
parameter. For example, if the Zone Cooling Setpoint parameter is set to 75ºF and the Clg
Deadband parameter is set to 2ºF the dead band around the set point would be from 76.0ºF to
74.0ºF.
Clg Period is an adjustable item which sets the “sampling time” used in the PI control
function to vary the DAT Clg Spt in zone control applications.
Clg Gain is an adjustable item which sets the “proportional band” used in the PI control
function to vary the DAT Clg Spt in zone control applications.
.Clg PAT is an adjustable item which sets the “project ahead” used in the PI control function
to vary the DAT Clg Spt in zone control applications.
Max Clg Change is an adjustable item that sets the maximum value for an increase or
decrease of the DAT Clg Spt in zone control applications.
Zone Htg DB is an adjustable item which sets a dead band around the Zone Heating Setpoint
parameter. For example, if the Zone Heating Setpoint parameter is set to 70ºF and the Htg
Deadband parameter is set to 2ºF the dead band around the set point would be from 69.0ºF to
71.0ºF.
Htg Period is an adjustable item which sets the “sampling time” used in the PI control
function to vary the DAT Htg Spt in zone control applications.
Htg Gain is an adjustable item which sets the “proportional band” used in the PI control
function to vary the DAT Htg Spt in zone control applications.
Htg PAT is an adjustable item which sets the “project ahead” used in the PI control function to
vary the DAT Htg Spt in zone control applications.
Max Htg Chg is an adjustable item that sets the maximum value for an increase or decrease of
the DAT Htg Spt in zone control applications.
Table 29: Zone Temperature Setup Menu
Menu Display Name Item Display Name Default Setting Range Password Level
Zone Temp Setup Ctrl Temp Src= RAT RAT 4
Space
MAT
OAT
Use Tstat Spt= No No 4
Yes
Zone Clg DB= 2.0d°F 0.0-10.0d°F 4
Clg Period= 60s 0-999s 4
Clg Gain= 0.1 0.0-100.0 4
Clg PAT= 600s 0-999s 4
Max Clg Chg= 5.0d°F 0.0-50.0d°F 4
Zone Htg DB= 2.0d°F 0.0-10.0d°F 4
Htg Period= 60s 0-999s 4
Htg Gain= 0.1 0.0-100.0 4
Htg PAT= 600s 0-999s 4
Max Htg Chg= 5.0d°F 0.0-50.0d°F 4