beautypg.com

Viconics VBZS Engineering Guide Specifications User Manual

Page 5

background image

The controller shall be capable of operating the packaged unit even if there is a loss of
communication with the zone controllers. The packaged unit will run in heating or cooling based
on the return air temperature. If there is no return air sensor installed, the controller shall
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