Viconics VBZS Engineering Guide Specifications - Manual (Page 4)

VZ7656x1000B BACnet Rooftop or Heat Pump Controller
The Rooftop unit Controller shall be:
VZ7656R1000B: Up to two heating and two cool stages, single fan speed output, 0-10Vdc output for
bypass damper or variable-frequency drive (VFD).
VZ7656F1000B: Modulating 0-10Vdc heating / 2 cooling stages, single fan speed output, 0-10Vdc output
for bypass damper or variable-frequency drive (VFD).
VZ7656E1000B: Up to two heating and two cooling stages, single fan speed output, 0-10Vdc output for
economizer actuator, 0-10Vdc output for bypass damper or variable frequency drive (VFD), indoor air
quality sequence (IAQ)
The Heat Pump Controller shall be:
VZ7656H1000B: 2 stage compressor with reversing valve and auxiliary heat, single fan speed output, 0-
10Vdc output for bypass damper or variable-frequency drive (VFD)
General VZ7656 Specifications:
VZ7656 controller shall be capable of controlling single or multistage HVAC units with automatic
changeover based on zone demands using the BACnet MS_TP communication protocol on
RS485.
The controller shall have the option of analyzing the PI heating or PI cooling demands from the
zones the following ways depending on the application:
1. Highest: The highest PI heating or PI cooling demand from the selected
voting zones shall dictate heating or cooling operation of the Rooftop Unit
controller.
2. Average of the three (3) highest demands: The average of the three (3)
highest PI heating or PI cooling demands from the selected voting zones will
dictate heating or cooling operation of the Rooftop Unit controller.
3. Average of the five (5) highest demands: The average of the five (5)
highest PI heating or PI cooling demands from the selected voting zones will
dictate heating or cooling operation of the Rooftop Unit controller.
The controller shall be capable of maintaining the system static pressure set point using
integrated proportional static pressure logic to modulate a bypass damper. A pressure transducer
with a 0-5Vdc output shall be wired directly to the VZ7656 controller. The controller shall have an
adjustable static pressure sensor range from 0-
5” W.C. The control will output an analog signal
from 0-10Vdc to the bypass damper. A control system requiring a separate bypass damper
controller or separate sensors to display the bypass damper position is not acceptable.
The controller shall have EEPROM memory to prevent a loss of programming due to power
outage as well as a minimum of 6-hour reserve time for the internal clock.