17
Many configuration and normal operation factors can limit action to the heating and cooling stages. Some
example of this would be:
-
Heating or cooling lockout based on outdoor air temperature ( configuration )
-
Heating or cooling lockout based on supply air temperature ( configuration )
-
Heating or cooling lockout based on anti-cycling ( configuration or RTU control card )
-
Fixed 2 minutes delay when RTU toggles from heating to cooling and vice-versa ( operation )
The RTU thermostat will then forward data to the zone thermostats:
•
Current central system occupancy
•
Current zone sequence to use ( hot air or cold air being delivered )
•
Outdoor air temperature
3B) Occupancy and Overrides
The occupancy of the zones is controlled by the schedule in the RTU thermostat.
-
When this schedule output value is unoccupied (as shown on the RTU thermostat display), then
the attached zones will be unoccupied mode.
-
When this schedule output value is occupied (as shown on the per RTU thermostat display), then
the attached zones will be either in occupied mode or stand-by mode if local PIR function is used.
It is possible to use remote scheduling though either BI1 or to use a remote time clock contact closure or a
BACnet network occupancy command. This will disable the local schedule occupancy function to the
zones. For more information on BACnet, please refer to global override section of the zoning system
integration guide. The whole system and all attached zones can only be initiated at the RTU thermostat
level. This is done by using the local user menu at the RTU thermostat or by configuring the extra digital
input (DI1) for a remote override button if it is required to be installed centrally.
Any zone overrides will trigger the necessary heating or cooling action for the required zones only. All other
attached zones not requiring an override will remain in the unoccupied state.
3C) RTU interface Lockouts
RTU thermostat can have functions locked out for the local user. This can prevent unwanted inputs to the
system as a whole when the RTU thermostats are installed in public areas or when certain local user
interface functions of the RTU thermostats are to be prevented.
Lock level is access through the Lockout configuration parameter. Please set the appropriate level for each
individual zone in the system according to their requirements.
VZ76 Thermostat Lockout Level Configuration Value
0
1
2
Global override function through the user menu
Yes Yes No
System mode access through the user menu
Yes No
No
Local schedule access through the user menu
Yes No
No
Local clock setting through the user menu
Yes Yes Yes
