Viconics VWZS Application Guide
Viconics Zoning System Application Guide
VZ7260X5x00W and VZ7656X1000W Controllers
VWZS_Rel2_Application_Guide-E02
(R1 Issue Date: January 10th, 2012)
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Table of Contents:
Please refer to the installation manuals of the zoning system controllers for all required information
related to wiring, installation, commissioning and integration:
• For detailed information on the Viconics VZ72xx Zone controller, please refer and read the VZ72xx Product
Guide. Installation and commissioning information is available on document: LIT-VZ7260X-Exx
• For detailed information on the Viconics VZ76xx RTU controller, please refer and read the VZ76xx Product
Guide. Installation and commissioning information is available on document: LIT-VZ7656X-Exx
1. System Overview and Architecture
A. Initial design criteria considerations
B. Scalability and limitations
C. Using local zone reheat or not using local reheat
D. Atypical zone areas
E. By-pass damper design rules
F. Indoor Air Quality Control Standards
2. Zone controllers VZ7260X5x00W operation
A. Demand based heating and cooling systems
B. Overrides and user zone interface lockouts
C. Zone setpoint limits
D. Heating and cooling weight zone selection
E. Minimum, maximum and maxheatflow adjustments
F. Terminal reheat lockout
G. Passive infra red motion detector cover (PIR)
H. AI4 CO2 / Other Sensor Input Operation
I. Disable Minimum Position parameter
J. Heating and Cooling Performances
3. RTU controllers VZ7656X1000W operation
A. Operation data exchanged
B. Occupancy and overrides
C. RTU interface lockouts
D. RTU heating and cooling supply air temperature lockouts
E. RTU heating and cooling outdoor air temperature lockouts
F. Critical mid-season changeover
G. By-pass damper control and operation
H. Minimum Supply Heat Temperature Control and Lockout
I. Indoor Air Quality Control & Operation
4. Wireless Communication system overview
A. (SA) Stand-Alone System implementation
B. (NS) Networked System implementation
C. Basic Initial Design And Deployment Consideration
D. Communication status LED and troubleshooting
5. System commissioning
A. Proper commissioning ZN controllers
B. Proper commissioning RTU controllers
C. Operational system checklist
6. Notes, tips and things you need to know
A. Single 24 VAC zone transformer vs. multi 24 VAC zone transformers
B. Critical point checks
C. Balancing and capacity
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1) System Overview and Architecture
The Viconics Zoning System product is comprised of 2 controller types.
• The VZ7260X5x00W zoning controller
• The VZ7656X1000W RTU / HP controller
When combined, they deliver a simple and efficient demand based system implementation which controls
pressure dependent VAV zones with roof top units (RTU). The system is designed to work with small to
medium sized RTU staged heating and cooling equipment (2 to 20 tons).
The system can be used either in a stand-alone system mode or seamlessly integrated into Niagara AX®
Workbench environment with the usage of a Viconics JACE communication and its associated driver.
The Viconics VZ7260X5x00W Wireless zone controller family is specifically designed for local pressure
dependent VAV zone control within the Viconics zoning system product family. The primary damper output
uses a common 0 to 10 VDC VAV actuator for control.
The product features a backlit LCD display with dedicated function menu buttons for simple user operation.
Accurate temperature control is achieved due to the product’s PI proportional control algorithm, which
virtually eliminates temperature offset associated with traditional, differential-based controllers.
The Zone controllers are also compatible with the new Viconics PIR cover accessories. Controller is
equipped with a PIR cover which provides advanced active occupancy logic. The system will automatically
switch occupancy levels from occupied to stand-by and unoccupied as required when activity is detected or
not detected by the unit. This advanced occupancy functionality provides valuable energy savings during
occupied hours without sacrificing occupant comfort. All zone controllers can be ordered with or without a
factory installed PIR cover.
The following hardware is required for operation of the zone controllers but not included:
• 24 VAC power supply. Dedicated to a single zone or many zones
• An analog 0 to 10 VDC pressure dependent actuator
• Terminal reheat if required by the design
• Proper wiring of all components as per the installation manual
• Proper network wires pulled through all devices communication connections
The Viconics VZ7656X1000W Wireless controller is specifically designed for equipment control based on
the zone demands.
The product also features a backlit LCD display with dedicated function menu buttons for simple operation.
Accurate temperature control is achieved through to the product’s PI proportional control algorithm, which
virtually eliminates temperature offset associated with traditional, differential-based controllers.
These controllers also contains extra digital inputs, which can be set by the user to monitor filter status or
can be used as a general purpose service indicator. All models contain a SPST auxiliary switch, which can
be used to control lighting or disable the RTU economizer function during unoccupied periods. It also
features a discharge air sensor input. Proportional static pressure logic (input and output) has been
integrated onto the controller to provide a complete single packaged unit for most small to medium size
jobs.
The following hardware is required for operation of the RTU controllers, but not included:
• 24 VAC power supply. Typically taken directly from the RTU power supply (C & RC)
• An outdoor air sensor (Viconics S2020E1000)
• A supply air duct sensor (Viconics S2000D1000)
• A return air duct sensor (Viconics S2000D1000)
• A 0 to 5 VDC static pressure sensor and transducer
• An analog 0 to 10 VDC by-pass damper actuator (spring-return or not)
• Proper wiring of all components as per the installation manual
• Proper network wires pulled through all devices communication connections
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Zone Controllers Available Models & Features:
iconics Part
Number
Control
Outputs
PIR Cover
VZ7260F5000W VZ7260F5500W VZ7260C5000W VZ7260C5500W
2 x Analog 0 to 10 VDC
1 x Auxiliary reheat
contact
PIR cover ready. PIR cover factory installed PIR cover ready PIR cover factory installed
2 x Analog 0 to 10 VDC
1 x Auxiliary reheat
contact
2 x Tri-state floating
1 x Auxiliary reheat
contact
2 x Tri-state floating
1 x Auxiliary reheat contact
Master Controllers Available Models & Features:
iconics Part
Number
Controlled
Equipment
Main Control
Outputs
Unique
Features
VZ7656R1000W VZ7656H1000W VZ7656F1000W VZ7656E1000W
Rooftop Unit Heat Pump Unit Rooftop Unit Rooftop Unit
2H / 2C 3H / 2C 0-10VDC Analog Heat / 2C 2H / 2C
- Reversing
Valve Output
-
- 0-10VDC Analog Heat
Output
- Minimum Supply Air
Temperature Control
- 0-10VDC Fresh Air Damper Output
- 0-5VDC Airflow Sensor Input
- CO2 Level Control Sequence
- Free Cooling Economizer Sequence
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Wireless System Overview
Viconics VZ72605x00W zone controllers are used in conjunction with the VZ7656X1000W roof top
controller controllers. When combined, they operate typical single or multistage RTUs and their
associated local zones. The system operates the same as in the BACnet MS-TP wired version, but
operate using ZigBee/IEEE 802.15.4 physical layer for the communication bus.
Typical Wireless zoning system installation
Please refer to the following Viconics documents for detailed information and design guidelines for the wireless zoning system version:
The following documents are available at: www.viconics.com
• For detailed information on the Viconics VZ72xx zone controller, please refer and read the VZ72xx Product Guide. Installation and
commissioning information is available on document: LIT-VZ7260_W-Exx
• For detailed information on the Viconics VZ76xx RTU controller, please refer and read the VZ76xx Product Guide. Installation and
commissioning information is available on document: LIT-VZ7656_W-Exx
• PIR cover installation information is available on document: PIR Cover Installation-Exx
• Information on Wireless integration is available in the following documents: MAN_Wireless Stat Driver Guide-Exx & ITG-VWG-
50-BAC-Exx.
The system can be used in fully stand-alone mode or in communication mode with the Viconics VWG /
Jace-Driver set to expose the controller(s) objects externally.
(SA) Stand-Alone applications: Where zoning system(s) are self sufficient for communication and no
external communication is required. In this configuration, the VZ76xx RTU controller acts as the network
coordinator. (More than one can be installed in a typical building application).
(NS) Networked Systems: Where zoning system(s) are required to communication with the Viconics
VWG and Jace-Driver set. In this configuration, the Viconics VWG and Jace-driver acts as the network
coordinator. (More than one can be installed in a typical building application).
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1A) Initial Design Criteria Considerations
The scope of this document is not intended to be a resource or white paper on VAV zoning system design.
There are many good resources available on the subject of VAV zoning systems and their associated
advantages and disadvantages. Please consult these resources for further information on this subject.
It is the responsibility of the designer and installer to ensure the following considerations are met:
• Size the installed equipment for properly calculated heating and or cooling peak loads. There are no
advantages to over sizing the system’s capacity to more than what is required as this simply leads to
short cycling of the equipment during small load periods.
• Properly size and layout all ductworks including the by-pass damper according to local codes and
standards in effect.
• Properly size the capacity of the zones according to the actual requirements of the room. Using
square footage calculations only can create situations where the installed total deliverable load may
be insufficient for the actual intended use of an area. Conference rooms, computer rooms, cafeterias
or other rooms where large gatherings occur would be a prime example of this scenario.
It is not the mandate of the zoning control system to correct for wrong initial mechanical layout and or load
calculations of the mechanical equipment. The control system will attempt to deliver the loads required by
master demanding zones by distributing the total available capacity of the installed equipment to the
required demanding areas. If the equipment is undersized for the required peak loads, the control system
will distribute the available capacity according to the priorities requested hence making most of the areas
comfortable.
Proper planning and design will always result in a job site being up and running faster with less service
calls during the initial occupancy period.
1B) Scalability and Limitations
The system is fully scalable in terms of number of Zone controllers and RTU controllers used on the same network layer (BACnet MS-TP or Wireless models).
Wireless controller systems overview:
(SA) Stand-Alone systems. There are no supervisory devices installed in this configuration.
In this application, the VZ76xx controller(s) are the network coordinators to their own system. I.E. they are
the network masters for each VZ72xx controller reporting to them. Each VZ76xx RTU controller and it’s
associated VZ72xx zone controllers use the same PAN ID and channel. The range of PAN ID on all
controllers to use is 251 to 500. This range is reserved for stand-alone (SA) system operation.
Smallest System Supported Largest System Supported
Single network of 127 nodes maximum
Number of Zones Number of RTUs Number of Zones Number of RTUs
1 ZN reporting to 1 RTU Minimum 63 ZN reporting to 1 RTU Minimum
There are no supervisory devices installed in this configuration. The system fully operates in stand-alone
mode.
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(NS) Networked Systems operation. There is a high-level supervisory device installed and used in this configuration.
In this application, a Viconics VWG and Jace-driver are the network coordinators for all controllers associated to the system and reporting their data point values.
Each VZ76xx RTU controller and its associated VZ72xx zone controllers will use the same PAN ID and
channel as the Viconics VWG and Jace-driver. The range of PAN ID on all controllers to use is 1 to 250.
This range is reserved for the networked system (NS) operation.
Smallest System Supported Largest System Supported
Single Network trunk of 128 nodes maximum
63 ZN reporting to 63 RTU Maximum
Number of Zones Number of RTUs Number of Zones Number of RTUs
1 ZN reporting to 1 RTU Minimum 126 ZN reporting to 1 RTU Minimum
In this configuration, there is a supervision device installed. The system will still fully operate in stand-alone
®
mode, but allows for a remote access to controller objects. It is seamlessly integrated into Niagara AX
Workbench environment with the use of the Viconics JACE communication device and its associated
driver.
Some added functions include:
- Detailed system graphics referred to as GUI’s which stands for Graphic User Interfaces
- Capacity to run remote trends, logs and diagnostics
- Capacity to use remote alarms for system events such as failures or maintenance
- Advanced and centralized energy management functions
- Remote scheduling
- Global outdoor temperature for all controllers
-
1C) Local Zone with Terminal Reheat or without Terminal Reheat
Including or excluding use of terminal reheat is dictated by design criteria’s of the installer. The use of
terminal reheat in a VAV system will always result in a more comfortable set-up for the occupants of the
space. However this may not be practical from a cost standpoint or regional requirements. System designs
will vary from Northern to Southern and Eastern to Western geographical locations because of the specific
regions peak load requirements.
In colder climates, VAV system heating operation without the use of terminal reheat typically always results
in colder outside walls. Although the zone dry-bulb temperature may be well maintained, it may be possible
for occupants not to be comfortable simply because of the low outside wall temperate.
Also, in the perimeter zones, the delivery process of the heating capacity from the ceiling is not as efficient
as when delivering the heating load directly where the losses occur such as in the case of a perimeter
electric baseboard or perimeter hydronic baseboard.
In regions where the heating load is small and required for only a small portion of the year, a properly sized
up zone VAV can deliverer the required heating demand and insure comfort without the use or terminal
reheat. However it is important to design the zone ductwork and area diffusers to be the most efficient with
air delivery close to the outside walls.
In certain problematic cases where air delivery may be an issue, the use of fan powered VAV units may
reduce the occupant discomfort by providing constant airflow to the zone and maximizing the air delivery
process.
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1D) Special Considerations
A typical office installation may require that a single unit service areas being used for different applications.
These areas will commonly be a combination of external and internal zones.
It is always good to verify the intended use of all areas knowing their true peak loads before committing to
its final design and sizing.
It may be necessary to oversize or undersize the design to meet their daily demands. The following are
examples of when over sizing of a zone damper may be needed:
• Areas with oversized windows that are exposed to the sun longer
• Conference rooms
• Cafeterias
• Areas with vending machines
• Areas with extra lighting
• Areas with computers, photocopier, etc…..
Areas such as computer rooms, kitchens and certain types of conference rooms may warrant a totally
separate system of their own and should not be part of the zones attached to an RTU. Certain critical areas
may call for cooling all year long and based on system settings could only guarantee occupant comfort a
portion of the year.
Knowing the critical areas of a building in advance and designing for them specifically will always result in a
more comfortable occupant. And it can be as simple as adding terminal reheat, radiant floor heating, a fan
powered VAV or even a separate small water source heat pump to critical area.
1E) By-Pass Damper Design Rules
A bypass damper is an airflow regulating device connected between the supply and return ducts. The
bypass damper will automatically open and bypass supply air normally delivered to the zone directly from
the supply to the return on a pressure rise when the VAV zone dampers are closing.
The by-pass damper should be sized to allow at least 70 to 80% of the nominal airflow of the RTU. A
simple way to determine if it is sized properly, assume all VAV zones are closed to their minimum position.
The by-pass should be large enough to re-circulate all the air from the RTU minus the amount set by the
minimum positions at the zones. A properly sized damper will result in an efficient and quiet operation.
1F) Indoor Air Quality Control Standards
The IAQ control is achieved by the VZ7656E1000B controller through CO2 level and minimum fresh air
control. The building CO2 level has to respect the local building codes. The recommended outdoor air flow
per the ASHRAE standard for office buildings (Air class 1) is as follows:
Table from: ASHRAE Standard 62.
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2) Zone Controllers VZ7260X5x00W Operation
The following information needs to be carefully read and properly understood if proper system
commissioning is to be achieved.
Contrary to low end commercial and residential zoning controllers which use a two positions open-close
actuator, Viconics VZ7260X5x00X uses proportional analog 0 to 10 VDC modulating damper actuator. This
enables performances and control sequences to be much closer to what is normally found in DDC
application specific control devices.
The operation of the zone controllers is intrinsically linked with the operation of their RTU controller.
Although it will operate in a stand-alone mode if the communication network is down, normal operation of
the system as a whole requires that communication with the RTU controller is functional.
Data exchanged from the zone controllers to the RTU controller:
• Current PI heating demand ( output value is based on PI heating weight configuration )
• Current PI cooling demand ( output value is based on PI cooling weight configuration )
Data exchanged from the RTU controller to the zone controllers:
• Current central system occupancy
• Current system mode active ( hot air or cold air being delivered )
• Outdoor air temperature
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2A) Demand Based Heating and Cooling System
System operation as a whole consists of selecting which zone controllers will have heating and cooling
weighted votes used by the RTU controller to which they are attached. The weighted heating and cooling
demand values from the selected master zones are then used by the RTU controller to determine if heating
or cooling action is required for the system as a whole.
Both internal and external zones are typically serviced by the same unit. This means that the system may
be exposed to conflicting heating and cooling demands in mid-seasons. The conflicting demand conditions
are addressed with the heating and cooling lockouts based on the outside air temperature value at the
RTU.
The heating or cooling action at the zone is dependent on how the RTU controller treats and calculates
what will be delivered point in time to the zones. Many factors can influence the delivery or availability of
hot air or cold air to satisfy the current zone demand point in time.
The following is an example of a RTU system mode calculation based on highest, average of the three
highest demands or the average of the five highest demands.
• RTU system mode calculations based on, average of the three highest demands or average of
the five highest demands.
•
Example 1 with 3 voting master zones only
oting Zone 1 Voting Zone 2 Voting Zone 3 RTU Control Type
Current heat
demand
50% 0% 0%
Heat weight set Heat weight set Heat weight set
50% 100% 100%
Resulting heat
weight to RTU
25% 0% 0% 25% 8.3%
Current cool
demand
0% 100% 100%
Cool weight set Cool weight set Cool weight set
100% 100% 50%
Resulting cool
weight to RTU
0% 100% 50% 100% 50%
Current heat
demand
Resulting heat
weight to RTU
Current cool
demand
Resulting cool
weight to RTU
Current heat
demand
Resulting heat
weight to RTU
Current cool
demand
Resulting cool
weight to RTU
Highest Average of 3
highest
It can be seen here that the resulting demand used by the RTU controller for the three master voting
zones are different and will result in different heating and cooling actions simply based on the RTU
configuration.
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V
V
V
V
V
V
Example 2 with 3 voting master zones only
oting Zone 1 Voting Zone 2 Voting Zone 3 RTU Control Type
Current heat
demand
100% 0% 0%
Heat weight set Heat weight set Heat weight set
100% 100% 100%
Resulting heat
weight to RTU
100% 0% 0% 100% 33.3%
Current cool
demand
0% 100% 100%
Cool weight set Cool weight set Cool weight set
100% 75% 75%
Resulting cool
weight to RTU
0% 75% 75% 75% 50%
Current heat
demand
Resulting heat
weight to RTU
Current cool
demand
Resulting cool
weight to RTU
Current heat
demand
Resulting heat
weight to RTU
Current cool
demand
Resulting cool
weight to RTU
Highest Average of 3
highest
It can be seen here that the resulting demand used by the RTU controller for the three master voting
zones are different and will result in different heating and cooling action simply based on the RTU
configuration.
• If the RTU is set to Control Type = Highest demand, the current action delivered by the RTU
will be heating.
• If the RTU is set to Control Type = Average of 3 Highest demand, the current action
delivered by the RTU will be cooling.
Example 3 with 5 voting master zones only
oting
Zone 1
Current heat
demand
100% 0% 50%% 50% 0%
Heat weight
set
100% 100% 100% 50% 100%
Resulting
heat weight
to RTU
100% 0% 50% 25% 0% 100% 58.3% 35%
Current cool
demand
0% 100% 0% 0% 100%
Cool weight
set
100% 50% 50% 50% 75%
Resulting
cool weight
to RTU
0% 50% 0% 0% 75% 75% 41.7.3% 25%
oting
Zone 2
Current heat
demand
Heat weight
set
Resulting
heat weight
to RTU
Current cool
demand
Cool weight
set
Resulting
cool weight
to RTU
oting
Zone 3
Current
heat
demand
Heat
weight set
Resulting
heat
weight to
RTU
Current
cool
demand
Cool
weight set
Resulting
cool
weight to
RTU
oting
Zone 4
Current
heat
demand
Heat
weight set
Resulting
heat
weight to
RTU
Current
cool
demand
Cool
weight set
Resulting
cool
weight to
RTU
oting
Zone 5
Current
heat
demand
Heat
weight set
Resulting
heat
weight to
RTU
Current
cool
demand
Cool
weight set
Resulting
cool
weight to
RTU
RTU Control Type
Highest Average
of 3
highest
Average
of 5
highest
It can be seen here that the resulting demand used by the RTU controller for the five master voting
zones are different and will result in different heating action simply based on the RTU configuration.
Please note that the heating or cooling action delivered to the zones is also dependent on heating
and cooling lockout functions based on the outdoor and supply air temperature. Please see the next
section for more information.
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2B) Overrides and User Zone Interface Lockouts
Each zone controller can have a function locked out for the local user. This can prevent unwanted inputs to
the system as a whole when the zone controllers are installed in public areas or when certain local user
interface functions of the zone controllers 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.
VZ72xx Controller Lockout Level Configuration Value 0 1 2 3
Local occupied setpoint access using the Up and Down arrow keys Yes Yes Yes No
Pressing the local override key will only command the local override function
Yes Yes No No
only, However the local heating and cooling demands are not sent to the RTU
controller and the central system will not restart.
Typically used only when perimeter reheat is used and re-started during an
override period.
Pressing the override key allows an override for this zone controller only.
Pressing the local override key will command the local override function and
Yes No No No
allow the local heating and cooling demands to be sent to the RTU controller.
This will have for effect of re-starting the central system and allow delivery of hot
or cold air based on the current local demand.
Pressing the override key allows an override for this zone controller only. All
other zones although being delivered hot or cold air will still be in unoccupied
mode and using their unoccupied setpoints.
Pressing local keys that have their function locked out will display a “keypad lock” message on the zone
controller display.
If a global override is required for the whole system and all zones return to occupied mode, then the
override needs to be enabled at the RTU controller itself. This can be accomplished by using the local user
menu at the RTU controller or configuring the extra digital input as a remote override button if the location
of the override button is required to be installed centrally.
2C) Zone Set point Limits
It cannot be stressed enough that you must take caution and properly explain to the user or tenants of the
building or system that a demand based heating or cooling system is designed to respond to actual local
demand of a number of selected zones. Even if the local demand cannot be meet by the central system.
For the following reason it is recommended to “limit” the set point adjustments of any zone controller that
have actual demand voting capacity at the RTU controller. It is also recommended to limit set points of all
zones even if they are not voting on central RTU demand.
This will prevent any local set point adjustments that may create heating or cooling locking conditions at the
RTU controller by having local set points that are not reachable. It also avoids any master voting controller
from having unreasonable authority over the zoning system.
Ex.: If a local user sets the current occupied set point to 62
°F, the PI weighted demand sent by this zone to
the RTU controller will always be at its maximum value.
Configuration Parameter Factory Default Value Recommended Settings
Heat max
Default: 90 °F (32 °C) 75 °F (24 °C)
Maximum local heating setpoint limit
Cool min
Default: 54 °F (12 °C) 68 °F (20 °C)
Minimum local cooling setpoint limit
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