Viconics VWZS Engineering Guide Specifications - Manual (Page 4)

automatically revert to the internal temperature sensor. Control systems that cannot operate the
packaged during a loss of communication with the zones are not acceptable.
The VZ7656 controller shall be 7 day programmable with a choice of 2 or 4 events per day.
Control systems that require an external time clock are not acceptable.
The controller shall have an adjustable (from 0 to 5 minutes) minimum On/Off operation time of
cooling & heating stages to prevent cycling.
The controller shall have a connection for an outdoor air temperature sensor. The outdoor air
temperature readings shall be used to lockout the system heating or cooling modes to prevent
equipment cycling as well as to lockout zone auxiliary heating (duct furnace and/or perimeter
heater).
The controller shall have a connection for a remote discharge air temperature sensor. The
discharge air temperature readings shall be used for monitoring purposes and can be
viewed directly on the LCD screen. The controller must have an adjustable discharge air
heating high-limit range of 70°F to 150°F (21°C to 65°C) as well as a discharge air cooling
low-limit range of 35 to 65°F (2.0°C to 19.0°C).
The controller shall have a connection for a remote return air temperature sensor. The
return air temperature readings shall be used for monitoring purposes as well as a backup
to controlling the RTU in case of a loss of communication with the zone controllers. The
return air temperature can be viewed directly on the LCD screen. The controller must have
an adjustable return air heating high limit and return air cooling low limit.
The controller shall have a lockable keypad with the following three lockout levels to prevent
changes to the settings from the keypad:
Global Unocc
Override
System mode
setting
Schedule setting Clock setting
Levels Override **
….Y/N
Sys mode
set Y/N
Schedule
set Y/N
Clock
set Y/N
0 Yes access Yes access Yes access Yes access
1 Yes access No access No access Yes access
2 No access No access No access Yes access
The controller shall have the ability to set the programmed occupied schedule time as the time at
which the desired occupied temperature set points will be attained at the zones. The controller
shall automatically optimize the equipment start. This progressive recovery feature can be
enabled or disabled.
The controller must have a programmable digital input that can be setup for the following
functions:
1. Service: a backlit flashing “SERVICE” alarm will be displayed on the
controller LCD screen when the input is energized.
2. Filter: a backlit flashing “FILTER” alarm will be displayed on the controller
LCD screen when the input is energized. The input can be tied to a
differential pressure switch to monitor filter status.
3. Remote NSB: Timer clock input for remote night-setback. This function shall
automatically disable the internal scheduling.
4. Remote OVR: Temporary occupancy remote contact. This function shall
disable all override menu functions.
The controller shall have “Smart Fan” operation to reduce energy consumption during unoccupied
periods.
The controller shall a fan delay that extends fan operation by 60 seconds after calls for heating or
cooling stage operation ends (can be enabled or disabled by the local keypad).
The controller shall have a configurable SPST output relay that can be used for lighting, exhaust
fan or fresh air control.