Viconics VZ7200F5x00W User guide

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Viconics Zoning System Application Guide
VZ7200F5x00W and VZ7656B1000W Thermostats
Wireless_Zoning_System_Guide-E10
(028-6020 R1 Issue Date: July 13, 2010)

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Table of Contents:
Please refer to the installation manuals of the zoning system thermostats for all required information
related to wiring, installation, commissioning and integration:
•For detailed information on the Viconics VZ72xx Zone thermostat, please refer and read the VZ72xx Product
Guide. Installation and commissioning information is available on document: LIT-VZ7200W-Exx
•For detailed information on the Viconics VZ76xx RTU thermostat, please refer and read the VZ76xx Product
Guide. Installation and commissioning information is available on document: LIT-VZ7600W-Exx
•Information on 3rd party BACnet integration, is available on document ITG-VZ7xxx-BAC-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
2. Zone thermostats VZ7200F5x00W 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)
3. RTU thermostats VZ7656B1000W 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
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 thermostats
B. Proper commissioning RTU thermostats
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 thermostat types.
•The VZ7200F5x00W zoning thermostat
•The VZ7656B1000W RTU thermostat
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 VZ7200F5x00W Wireless Zone thermostat 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 thermostats.
The Zone thermostats are also compatible with the new Viconics PIR cover accessories. Thermostat 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 thermostats can be ordered with or without a
factory installed PIR cover.
The following hardware is required for operation of the zone thermostats 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 VZ7656B1000W Wireless Roof Top Unit (RTU) thermostat is specifically designed for
equipment control based on the zone demands.
The RTU thermostat has been designed for single stage or multi-stage control of heating and cooling
equipment such as rooftop and self-contained units used in zoning systems.
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 thermostats.
The thermostat 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 thermostat to provide a complete single packaged unit for most small to medium size jobs.
The following hardware is required for operation of the RTU thermostats, 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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Wireless System Overview
Viconics VZ72005x00W zone thermostats are used in conjunction with the VZ7656B1000W roof top
controller thermostats. 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 thermostat, please refer and read the VZ72xx Product Guide. Installation and
commissioning information is available on document: LIT-VZ7200_W-Exx
•For detailed information on the Viconics VZ76xx RTU thermostat, 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 thermostat(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 thermostat 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 thermostats and RTU thermostats used on the
same network layer (BACnet MS-TP or Wireless models).
Wireless thermostat systems overview:
(SA) Stand-Alone systems. There are no supervisory devices installed in this configuration.
In this application, the VZ76xx thermostat(s) are the network coordinators to their own system. I.E. they are
the network masters for each VZ72xx thermostat reporting to them. Each VZ76xx RTU thermostat and it’s
associated VZ72xx zone thermostats use the same PAN ID and channel. The range of PAN ID on all
thermostats to use is 251 to 500. This range is reserved for stand-alone (SA) system operation.
Smallest System Supported Largest System Supported
Number of Zones Number of RTUs Number of Zones Number of RTUs
Single network of 127
nodes maximum 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 thermostats
associated to the system and reporting their data point values.
Each VZ76xx RTU thermostat and its associated VZ72xx zone thermostats will use the same PAN ID and
channel as the Viconics VWG and Jace-driver. The range of PAN ID on all thermostats to use is 1 to 250.
This range is reserved for the networked system (NS) operation.
Smallest System Supported Largest System Supported
Number of Zones Number of RTUs Number of Zones Number of RTUs
Single Network trunk of
128 nodes maximum 1 ZN reporting to 1 RTU Minimum 126 ZN reporting to 1 RTU Minimum
63 ZN reporting to 63 RTU Maximum
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 thermostat 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 thermostats
-
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.
2) Zone Thermostats VZ7200F5x00W 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 thermostats which use a two positions open-close
actuator, Viconics VZ7200F5x00X 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 thermostats is intrinsically linked with the operation of their RTU thermostat.
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 thermostat is functional.
Data exchanged from the zone thermostats to the RTU thermostat:
•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 thermostat to the zone thermostats:
•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 thermostats will have heating and cooling
weighted votes used by the RTU thermostat to which they are attached. The weighted heating and cooling
demand values from the selected master zones are then used by the RTU thermostat 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 thermostat 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
V
oting Zone 1
V
oting Zone 2
V
oting Zone 3 RTU Control Type
Current heat
demand
Current heat
demand
Current heat
demand
Highest Average of 3
highest
50% 0% 0%
Heat weight set Heat weight set Heat weight set
50% 100% 100%
Resulting heat
weight to RTU
Resulting heat
weight to RTU
Resulting heat
weight to RTU
25% 0% 0% 25% 8.3%
Current cool
demand
Current cool
demand
Current cool
demand
0% 100% 100%
Cool weight set Cool weight set Cool weight set
100% 100% 50%
Resulting cool
weight to RTU
Resulting cool
weight to RTU
Resulting cool
weight to RTU
0% 100% 50% 100% 50%
It can be seen here that the resulting demand used by the RTU thermostat 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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Example 2 with 3 voting master zones only
V
oting Zone 1
V
oting Zone 2
V
oting Zone 3 RTU Control Type
Current heat
demand
Current heat
demand
Current heat
demand
Highest Average of 3
highest
100% 0% 0%
Heat weight set Heat weight set Heat weight set
100% 100% 100%
Resulting heat
weight to RTU
Resulting heat
weight to RTU
Resulting heat
weight to RTU
100% 0% 0% 100% 33.3%
Current cool
demand
Current cool
demand
Current cool
demand
0% 100% 100%
Cool weight set Cool weight set Cool weight set
100% 75% 75%
Resulting cool
weight to RTU
Resulting cool
weight to RTU
Resulting cool
weight to RTU
0% 75% 75% 75% 50%
It can be seen here that the resulting demand used by the RTU thermostat 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
V
oting
Zone 1
V
oting
Zone 2
V
oting
Zone 3
V
oting
Zone 4
V
oting
Zone 5 RTU Control Type
Current heat
demand
Current heat
demand
Current
heat
demand
Current
heat
demand
Current
heat
demand
Highest Average
of 3
highest
Average
of 5
highest
100% 0% 50%% 50% 0%
Heat weight
set
Heat weight
set
Heat
weight set
Heat
weight set
Heat
weight set
100% 100% 100% 50% 100%
Resulting
heat weight
to RTU
Resulting
heat weight
to RTU
Resulting
heat
weight to
RTU
Resulting
heat
weight to
RTU
Resulting
heat
weight to
RTU
100% 0% 50% 25% 0% 100% 58.3% 35%
Current cool
demand
Current cool
demand
Current
cool
demand
Current
cool
demand
Current
cool
demand
0% 100% 0% 0% 100%
Cool weight
set
Cool weight
set
Cool
weight set
Cool
weight set
Cool
weight set
100% 50% 50% 50% 75%
Resulting
cool weight
to RTU
Resulting
cool weight
to RTU
Resulting
cool
weight to
RTU
Resulting
cool
weight to
RTU
Resulting
cool
weight to
RTU
0% 50% 0% 0% 75% 75% 41.7.3% 25%
It can be seen here that the resulting demand used by the RTU thermostat 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 thermostat can have a function locked out for the local user. This can prevent unwanted inputs
to the system as a whole when the zone thermostats are installed in public areas or when certain local user
interface functions of the zone 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.
VZ72xx Thermostat 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
only, However the local heating and cooling demands are not sent to the RTU
thermostat 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 thermostat only.
Yes Yes No No
Pressing the local override key will command the local override function and
allow the local heating and cooling demands to be sent to the RTU thermostat.
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 thermostat only. All
other zones although being delivered hot or cold air will still be in unoccupied
mode and using their unoccupied setpoints.
Yes No No No
Pressing local keys that have their function locked out will display a “keypad lock” message on the zone
thermostat 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 thermostat itself. This can be accomplished by using the local
user menu at the RTU thermostat 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 thermostat that
have actual demand voting capacity at the RTU thermostat. 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 thermostat by having local set points that are not reachable. It also avoids any master voting
thermostat 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 thermostat will always be at its maximum value.
Configuration Parameter Factory Default Value Recommended Settings
Heat max
Maximum local heating setpoint limit
Default: 90 °F (32 °C) 75 °F (24 °C)
Cool min
Minimum local cooling setpoint limit
Default: 54 °F (12 °C) 68 °F (20 °C)

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2D) Heating and Cooling Weight Zone Selection
For any system to properly operate, care must be taken to select which zones will be driving the system
and their weight attached to the calculations.
The values below are provided as an initial rule of thumb and need to be re-evaluated on a job per job
basis depending on the specifics of the system design and layout.
Total number of
zones System layout Recommended initial
number of master voting
zones with weight
1 to 5 All internal or external zones 1 to 3
3 to 5 Mix and match of internal and external zones 2 to 3
6 to 20 Mix and match of internal and external zones 3 to 8
21 + Mix and match of internal and external zones 8 +
Notes regarding the master voting zones selection:
oNot all zones in the system need to be masters. A good rule of thumb is to provide a ratio of 1/3 to
1/2 of the total number of zones which can be master to the system.
oOn larger installations where internal zones are present in the system. I.E. zones not exposed to
an outside wall. The ratio of internal to external master zones should be in the approximate range
of 1 internal zone to 4 external zones.
oZones selected to be masters for demand calculations should represent either:
-Typical zones or areas that will be exposed to some of the highest peak heating and
cooling loads.
-Zones or areas that represent a significant portion of the equipment peak load capacity.
Example, if a system has five zones where a single zone represents ½ of the total MAX
CFM of the equipment, then for sure this zone needs to be master to the system.
-Zones or areas that are subject to temporarily larger occupancy need to be part of demand
calculations if the zones are to be expected to respond during those spikes of occupancy.
Typical examples are: Conference room, cafeteria and other such common areas.
Attaching a zone as a master to the system which is either undersized or was commissioned with
operational flaws and errors may result in erratic system behaviour by adding total demand that cannot be
met by the system.
Notes regarding the weight parameter value of the master zones:
oInternal zones do not need to affect heating demand calculations. They should only affect the
cooling demand calculations. Such zones will always call for cooling during occupied periods even
during winter. If they where to call for heating at a certain point in time, then the surrounding
external zones would typically already be in heating mode.
-It is possible for an internal zone to be slightly overcooled during peak summer cooling
loads because of the dampers minimum position during occupied periods. The RTU is
providing its maximum cooling capacity and the amount of cold air provided by the
minimum position is already providing more capacity to the internal zone.
-Alternately, it is also possible for an internal zone to be slightly overheated during peak
winter heating loads because of the dampers minimum position. During occupied periods
the RTU is providing its maximum heating capacity and the amount of hot air provided by
the dampers minimum position will provide more heat to the internal zone than necessary.

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oExternal zones considered of primary importance should have both their heating and cooling
weight set to 100%
oZones considered of secondary importance can have their weight set to a lesser value than 100%
to reflect their importance on the systems total voting when making demand calculations.
oDue to, their location, exposure, design, etc……, certain zones can have problematic behaviour
specifically in peak heating or cooling mode. (Ex.: when an office surrounded by panoramic
windows).
These zones can have their peak load demand satisfied. However this will be either at the expense
of energy used and or slightly overheating or overcooling the other zones.
It is the responsibility of the installer to properly identify any problematic areas and to determine if
those problematic areas are to be either fully satisfied or to simply leave them unsatisfied during
certain peak load periods in order to minimize energy consumption and to allow the rest of the
zones in the system to be optimized.
When dealing with the type of system which control many areas from a single central system, a
choice must be taken during set-up to either prioritize comfort or equipment cycling and energy
consumption.
-Adding many master voting zones (including problematic ones) to an RTU thermostat will
provide better comfort at the expense of higher energy consumption.
-Restricting the number of master voting zones (and excluding the problematic ones) to the
RTU thermostat will always provide a more energy efficient system at the expense of
comfort in certain areas.
2E) Minimum, Maximum and Heat flow Adjustments
Although system balancing can be accomplished by utilizing the thermostat’s built in configuration settings.
It is recommended to add a balancing side-takeoff damper on all zones. This will ensure that any
supplementary air can be reduced and will limit excessive noise due to airflow if the zones or associated
ductwork were improperly sized.
Minimum Position Adjustment (Min Pos)
This parameter sets the minimum amount of air being delivered to the zone. The VAV damper (when
powered) will never close below this value setting.
Maximum Position Adjustment (Max Pos)
This parameter sets the maximum amount of air being delivered to the zone; both in heating and cooling
mode. The VAV damper (when powered) will never open above this value setting.
Please note that the maximum amount of hot air delivered is set by this parameter, and NOT the Max Heat
flow parameter. Please refer to the next section for a description and usage of the Max Heat flow
parameter functions.

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Maximum Heatflow Adjustment (MaxHTPos)
Many installers will assume that this parameter sets the Maximum airflow of the VAV damper when the
RTU is delivering hot air. This is not the case. Both the maximum amount of cold AND hot air delivered to
the zone is set by the (Max Pos) zone damper parameter. Please see section above for more details.
The value set by this parameter will open the damper to a maximum heating position and will maximize hot
air flow when heat is requested with cold primary air using the duct reheat output.
The Max Heat flow function is only used if the local reheat configuration (RehtConf) is set to any value
except None. None = No local reheat. An example of this is a local reheat configuration using a duct
mounted reheat coil device.
Type of reheat
configured (RehtConf) BO5 reheat output time
base (BO5 Time
MaxHTPos value function and adjustment
0 = None N/A Leave default of 30% or any adjustment. MaxHTPos is not used in scenario
1 = Analog Duct Rht
Only
N/A Set to any value superior to the current selected minimum position. Ex. If the
minimum airflow is set at 25% and Max heat is set at 75%.
If primary is cold air; when the PI heating loop (and analog output ) goes
from 0 to 100%, the damper linearly move from 25% to 75% opening
2 = On/Off Duct Rht
Only
0= 15 minutes Set to any value superior to the current selected minimum position. Ex. If the
minimum airflow is set at 25% and Max heat is set at 75%.
If primary is cold air; when the BO5 output is energized on a call for heat, the
damper will directly move from 25% to a 75% position. As soon as BO5 is
de-energized, the damper will move back to 25% opening
1= 10 seconds for Solid
state relays
Set to any value superior to the current selected minimum position. Ex. If the
minimum airflow is set at 25% and Max heat is set at 75%.
If primary is cold air; when the PI heating loop (and pulsed BO5 output )
goes from 0 to 100%, the damper linearly moves from 25% to 75% opening
3 = On/Off Peri Rht Only 0= 15 minutes Leave default of 30% or any adjustment. MaxHTPos is not used in scenario
1= 10 seconds for Solid
state relays
Leave default of 30% or any adjustment. MaxHTPos is not used in scenario
4 = Analog Duct Rht &
On/Off Peri Rht
Set to any value superior to the current selected minimum position. Ex. If the
minimum airflow is set at 25% and Max heat is set at 75%.
If primary is cold air; when the PI heating loop (and analog output ) goes
from 0 to 100%, the damper linearly moves from 25% to 75% opening
-The selected zone dampers minimum position has a direct impact on the temperature stability for
certain zones. Having a minimum position selected may produce an over cooling or over heating
effect. This effect is created when the primary air temperature is in the inverse mode than that
which the zone currently requires. An example of this is when an internal zone is requesting
cooling during winter while the RTU is supplying hot air for the external zones.
Adjusting the minimum position of a zone damper is mandatory by NA standards. It is however the
choice of the installer to decide if in some cases removing it or lowering it to a value below
standard may solves a system design issue. A good example of this would be an internal zone with
a grossly oversized VAV unit.

14
How To Test and Balance the Minimum, Maximum and Heat Flow Values:
Balancing Minimum Air Flow
1. Be sure local system heating is allowed by setting the outdoor heating lockout value at the RTU
thermostat (H Lock)
2. Be sure the system is currently in heating mode. As viewed locally at the RTU thermostat by
pressing the manual scroll button and displaying the local Zone Sequence = Heat message prompt.
3. Be sure that the master voting zones are calling for heating by setting the appropriate set points
accordingly.
4. Set the currently balanced thermostat set point to its minimum value. An example of this would be
60F or when the set point is at least 7-8 F lower than the current room temperature. This will drive
the VAV zone to its minimum value.
5. Set the (Min Pos) configuration parameter to the desired value as required by balancing.
Balancing Maximum Air Flow
1. Be sure local system heating is allowed by setting the outdoor heating lockout value at the RTU
thermostat (H Lock)
2. Be sure the system is currently in heating mode. As viewed locally at the RTU thermostat by pressing
the manual scroll button and displaying the local Zone Sequence = Heat message prompt.
3. Be sure that the master voting zones are calling for heating by setting the appropriate set points
accordingly.
4. Set the currently balanced thermostat set point to its minimum value. An example of this would be 60F
or when the set point is at least 7-8 F lower than the current room temperature. This will drive the VAV
zone to its minimum value.
5. Set the (Max Pos) configuration parameter to the desired value as required by balancing.
Balancing Maximum Heat Flow
1. Be sure local system cooling is allowed by setting the outdoor cooling lockout value at the RTU
thermostat (C Lock).
2. Be sure local reheat is allowed by appropriately setting the outdoor reheat lockout value at the Zone
thermostat (AO2 OALK or BO5 OALK).
3. Be sure the system is currently in cooling mode. As viewed locally at the RTU thermostat by pressing
the manual scroll button and displaying the local Zone Sequence = Cool message prompt.
4. Be sure that the master voting zones are calling for cooling by setting the appropriate set points
accordingly.
5. Set the currently balanced thermostat set point to its minimum value. An example of this would be 60F
or when the set point is at least 7-8 F lower than the current room temperature. This will drive the VAV
zone to its minimum value.
6. Set the (MaxHTPos) configuration parameter to the desired value as required by balancing.
Please note that:
-0 to 100 % is directly converted to 0 to 10 Vdc on the VAV damper output. If the actuator has a
positioning input range of 2 to 10 Vdc, then entering 50% minimum position is not directly
converted to 50% VAV damper position. Please refer to table below
VAV damper
position required 0% 10% 20% 30% 40% 50% 60% 70% 80% 100%
Setting for 0-10
Vdc Actuator 0% 10% 20% 30% 40% 50% 60% 70% 80% 100%
Setting for 2-10
Vdc Actuator
0 to
20% 28% 36% 44% 52% 60% 68% 76% 84% 100%

15
-The damper position is never linear or proportional to airflow in a pressure dependent application.
Depending on how the zone damper was sized, a box may best slightly oversized, or slightly
undersized. In all cases, the PI loop (Proportional Integral) of the zone thermostat will always
compensate to find the proper required position to satisfy the current zone demand.
-Be sure the VAV actuator is properly installed and set-up so the VAV damper blade is able to
rotate from the fully opened, to fully closed position with no restriction to its mechanical rotation.
2F) Terminal Reheat Lockout
It is possible to lockout out the local terminal reheat function of the zones during hot seasons or when no
longer required. This prevents users from using the local reheat function simply based on a configured
outside air temperature value.
If RehtConf is set to AO2 OALK BO5 OALK
0 = None N/A, reheat not used N/A, reheat not used
1 = Analog Duct Reheat Only Set to desired value N/A BO5 not used by this reheat
sequence
2 = On/Off Duct Reheat Only N/A AO2 not used by this reheat
sequence
Set to desired value
3 = On/Off Perimeter Reheat Only N/A AO2 not used by this reheat
sequence
Set to desired value
4 = Analog Duct Reheat & On/Off
Perimeter Reheat
Set to desired value. Can be
different than BO5 OALK
Set to desired value. Can be
different than AO2 OALK
2G) Passive Infra Red Motion Detector Cover (PIR)
The Viconics zone thermostats are compatible with the new Viconics PIR (Passive Infra Red) cover
accessory. Thermostats equipped with a PIR cover provide advanced active occupancy logic, which can
automatically switch occupancy levels from occupied to stand-by as required when local activity is detected
in the room.
This advanced occupancy functionality provides advantageous energy savings during occupied hours
without sacrificing occupant comfort. All zone thermostats can be ordered with or without a factory installed
PIR cover.
This allows zones, which are infrequently occupied such as a conference room, storage areas or other
rooms to use relaxed set points during periods when there are no occupants present in the zone.
The advantage of using stand-by set points is to permit the system to recover fairly rapidly from stand-by to
occupied set points once movements are detected in a zone. The relaxed values of the stand-by setpoints
need to be far enough from occupied set points to optimise the energy savings a PIR cover can provide yet
close enough for the system to recover quickly and be within the occupants comfort zone in as short a time
as possible. If the span (Delta Temperature) from occupied to stand-by setpoints is too large, the zone will
not be able to recover quickly and the occupants will be left uncomfortable for the duration of the occupied
periods initiated by the PIR.
% opening
Air flow
% opening
Air flow
Oversized VAV
Undersized VAV
Effective
Control
Area
Effective
Control
Area

16
In order for the PIR logic function to be enabled, the following settings must be enabled at the zone
thermostat.
-If a local PIR cover is used, be sure to set the (PIR Func)parameter to ON.
-If a remote PIR sensor is used on BI1, be sure to set the (BI1) parameter to Motion NO or Motion
NC.
PIR logic
The PIR function is only used during occupied periods. If occupancy is desired during an unoccupied
period, simply press the local override button (if allowed by the local lockout level configuration). Then local
occupancy will toggle to Override (local occupied ) as per the ToccTimer time value for overrides.
Zone commanded occupied by the RTU schedule
Initial state when no movements
are detected by the PIR sensor
Stand-by
Initial movement detected by the
thermostat ( PIR cover or remote
PIR )
Occupied for 60 minutes after the last movement has been
detected. When the 60 minute timer value has expired and no new
movements have been detected, the thermostat will resume the
stand-by mode.
3) RTU Thermostats VZ7656B1000W Operation
The following information needs to be carefully read and properly understood if proper system
commissioning is to be achieved.
Unlike low end commercial or residential zoning thermostats which typically only use two position demand
or non- demand logic to initialize heating and cooling functions, Viconics VZ7656B1000X uses local PI
zone demand(s) to operate heating and cooling stages. Accurate temperature control in the zones is
achieved by the time proportional control algorithm. This enables performances and control sequences
much closer to what is normally found in DDC application specific control devices.
The operation of the RTU thermostat is linked with the operation of the attached zone thermostats.
Although the thermostat 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 attached zone thermostats is
functional.
3A) Operation Data Exchanged
Independently of the network layer being BACnet MS-TP or Wireless, the flow of data exchanged between
the zones and the RTU thermostat can be summarized as follow:
Heating and cooling demand data is first exchanged from the ZN thermostats to the RTU
thermostat:
•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 )
Each voting thermostat will also calculate is demand values based on their current occupancy mode and
setpoints currently in use: Unoccupied, Stand-By or Occupied.
Based on the control type configuration (CntrlTyp), the RTU thermostat will calculate the resulting heating
and cooling zone demands. (See section 2A) Demand Based Heating and Cooling System.
Proper action to the heating or cooling stages using the time proportional control algorithm is accomplished
based on heating or cooling values.
-If resulting calculated PI heating demand > resulting calculated PI cooling demand, then ZN
sequence is heating
-If resulting calculated PI cooling demand > resulting calculated PI heating demand, then zone
sequence is cooling
-If resulting calculated PI cooling demand = resulting calculated PI heating demand, then zone
sequence stays in last current mode

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

18
3D) RTU Heating and Cooling Supply Air Temperature Lockouts
One problematic aspect of any VAV zoning system is high demand for (heating or cooling) when most of
the zone VAV dampers are closed. This leads to most of the supply air being re-circulated through the
pressure by-pass and can lead to extremely hot or cold supply temperature.
-To prevent high supply temperatures (specifically with gas heating RTU), adjust discharge air
temperature high limit to required value.
Discharge air temperature high limit default value is: 80°F
Range is: 70°F to 150°F (21°C to 65°C) (increments: 0.5° or 5°)
-To prevent low supply temperatures (specifically to prevent freezing of RTU DX coils when a high
by-pass ratio is in effect ), adjust discharge air temperature low limit to required value.
Discharge air temperature low limit default value is: 55°F
Range is: 35 to 65°F (2.0°C to 19.0°C) (increments: 0.5° or 5°)
3E) RTU Heating and Cooling Outdoor Air Temperature Lockouts
H Lock and C Lock
-Parameter C Lock temperature disables the cooling stages based on the outdoor temperature.
-Parameter H Lock temperature disables the heating stages based on the outdoor temperature.
RTU mode lockouts need to be properly set to keep heating or cooling equipment cycling to a minimum. It
is the responsibility of the installer to decide if priority of the system will be given to comfort or not. The
adjustments for both lockouts will be different based on specific regions load requirements.
-A system located far north may require the RTU to deliver heating until a 75F outside air value is
attained due to the inertia of the building mass which will require heating during a cold night and
then will transition to a hot mid-season day.
-A southern system application may require the RTU to always deliver cooling and never lock up the
cooling mode while imposing strong restrictions on the heating side of the system.
Heating and cooling RTU equipment cycling will only happen within the overlapping dead band value left
between the H Lock and C Lock parameter adjustments. The tighter the value between these two
parameters, the less cycling will be encountered.
It is also possible to set the system to completely eliminate heating and cooling equipment cycling based
on outdoor air limitations if this type of operation is required. This of will have an impact on specific zone
performances.
Outside Air Temperature
Heat Lock = 75F
Cool Lock = 65F
Overlap = 10F
Outside Air Temperature
Heat Lock = 72F
Cool Lock = 72F
No Overlap
Outside Air Temperature
Heat Lock = 70F
Cool Lock = 75F
No Heat
No Cool
5F deadband

19
3F) Critical Mid-Season Changeover
Heating and cooling RTU equipment cycling during mid-seasons is inevitable with a zoning VAV system if
any degree of comfort is to be maintained.
A properly setup system will be able to deliver comfort to conflicting zone demands during the mid-season
period by alternating heating and cooling at the RTU.
Normally, a lot of the unwanted heating and cooling switchovers can be eliminated by authorizing terminal
reheat or by limiting the RTU heating or cooling capacity throughput based on the outdoor temperature ( H
Lock and C Lock ). However, limiting the RTU heating or cooling throughput based on outdoor
temperature will have an impact on control performance of certain zones when the required heating or
cooling capacity is not available due to the lockout conditions.
Typically, the number of RTU heating or cooling switchovers cycles during conflicting demand situations
will be around the same as the RTU CPH settings (Default of 4 cycles per hour for both heating and
cooling). This will translate into two cooling and two heating cycle periods per hour.
Also, the recorded RTU supply delta temperature and demand variances will always be higher when using
a highest demand control type operation versus an average demand method. Energy consumption is also
expected to be higher with a highest demand control type operation versus an average demand method of
calculating the system requirements.
3G) By-Pass Damper Control and Operation
The RTU thermostat has a built in static pressure control loop with an analog 0 to 10 Vdc by-pass damper
output. In order to operate, the static pressure control loop needs to have a static pressure sensor
connected to the static pressure input on the RTU thermostat (terminal SP).
The type of pressure transducer used needs to be of voltage type (0 to 5 Vdc) and have a 24 Vac half-
bridge power supply.
The range of the pressure transducer needs to be one of the following and needs to be properly configured
using the static pressure configuration parameter (SP range).
Static pressure transducer range.
Voltage input range is 0 to 5 Vdc.
•0 = 0 to 1.5 in WC
•1 = 0 to 2 in WC
•2 = 0 to 3 in WC
•3 = 0 to 4 in WC
•4 = 0 to 5 in WC
Typically, the static pressure sensor probe is installed 2/3 of the way down the main ventilation duct.
The static pressure set point is set by the configuration parameter (Pressure). The default value is 0.8” WC.
The range and adjustability of the set point is: 0 to 2 in WC (0 Pa to 500 Pa) (increments: 0.1” WC or 25
Pa).
Please note that the static pressure scale will automatically change from inches of WC to PA
(Pascals) when the local units’ configuration parameter is changed.
•0 = SI for Celsius / Pa pressure scale
•1 = Imp for Fahrenheit / in. WC pressure scale
Operation of the static pressure control loop is dependent on the fan running or not. For proper operation of
the control loop, the static pressure control actuator needs to be properly installed.
•Control signal = 0 Vdc = Static pressure damper fully closed = No air recirculation from supply to
return
•Control signal = 10 Vdc = Static pressure damper fully opened = Maximum air recirculation from
supply to return

20
Operation:
When the fan output is off (Terminal G), the static pressure control loop and the by-pass damper is fully
opened to 10 Vdc output. This will minimize the air pressure related noise during initial fan start-up. Please
note that the fan is always on during occupied periods and that it will cycle on demand with the heating and
cooling staged only during unoccupied periods.
When the fan output is on (Terminal G), the static pressure control loop is enabled and the by-pass damper
will modulate to maintain the desired static pressure set point according to the static pressure input reading
at the RTU thermostat. The current static pressure value can be read at the RTU thermostat at any time by
using the manual scroll function and displaying the pressure prompt.
4) Wireless Communication Overview
The Viconics VZ7200F5x00W and VZ7656B1000W thermostats, Viconics Wireless Gateway (VWG) and
Jace-driver and other related wireless thermostat family (VT7xxxXxxxxW) networkable devices operate
using ZigBee/IEEE 802.15.4 physical layer for communication.
General characteristics of the wireless physical communication layer are:
· Wireless physical layer of 2.4GHz with a data rates of 250 kbps
· Yields high throughput and low latency
· Automatic multiple topologies configuration: star, peer-to-peer, mesh
· Fully handshake protocol for transfer reliability
· Range: 30 feet / 10M typical (up to 100 feet / 30 M based on environment)
IEEE 802.15.4 along with ZigBee’s Network and Application Support Layer provide:
· Low cost installation deployment
· Ease of implementation
· Reliable data transfer
· Short range operation
· Very low power consumption
· Appropriate levels of security
The main network coordinator for the wireless the IEEE 802.15.4/ZigBee network can be either:
•The VZ76xx RTU thermostat for (SA) Stand-Alone applications: Where zoning system(s) are self
sufficient for communication and no external communication is required. In this layout, the VZ76xx RTU
thermostat acts as the network coordinator.
•The Viconics Wireless Gateway (VWG / Jace-Driver for (NS) Networked Systems applications: Where
zoning system(s) (more than one can be installed in a typical building application) are required to
communicate with the Viconics VWG / Jace-Driver set. In this layout, the Viconics VWG / Jace-Driver
acts as the network coordinator.
Many network specific features of the IEEE 802.15.4 standard are not covered in detail in this paper.
However, these are necessary for the efficient operation of a ZigBee network. The features of the network
physical layer include receiver energy detection, link quality indication and clear channel assessment. Both
contention-based and contention-free channel access methods are supported with a maximum packet size
of 128 bytes, which includes a variable payload up to 104 bytes. Also employed are 64-bit IEEE and 16-bit
short addressing, supporting over 65,000 nodes per network. All the properties of the physical layer are
used and employed by the Viconics mesh network but are hidden to the user for ease of configuration and
commissioning of the network database.