Viconics VWZS Application Guide

Download

Viconics Zoning System Application Guide

VZ7260X5x00W and VZ7656X1000W Controllers

VWZS_Rel2_Application_Guide-E02

(R1 Issue Date: January 10th, 2012)

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

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

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

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

• 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).

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.

(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.

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.

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

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.

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.

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

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:

o Not 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.

o On 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.

o Zones 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:

o Internal 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.

o External zones considered of primary importance should have both their heating and cooling

weight set to 100%

o Zones 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.

o Due 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 controller 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 controller 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 controller’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.

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)

0 = None N/A Leave default of 30% or any adjustment. MaxHTPos is not used in scenario

1 = Analog Duct Rht

Only

2 = On/Off Duct Rht

Only

1= 10 seconds for Solid

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

4 = Analog Duct Rht &

On/Off Peri Rht

BO5 reheat output time

base (BO5 Time

N/A Set to any value superior to the current selected minimum position. Ex. If the

0= 15 minutes Set to any value superior to the current selected minimum position. Ex. If the

state relays

Set to any value superior to the current selected minimum position. Ex. If the

MaxHTPos value function and adjustment

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

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

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

Leave default of 30% or any adjustment. MaxHTPos is not used in scenario

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.

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 controller (H Lock)

2. Be sure the system is currently in heating mode. As viewed locally at the RTU controller 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 controller 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 controller (H Lock)

2. Be sure the system is currently in heating mode. As viewed locally at the RTU controller 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.

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 controller (C Lock).

2. Be sure local reheat is allowed by appropriately setting the outdoor reheat lockout value at the Zone controller (AO2 OALK or BO5 OALK).

3. Be sure the system is currently in cooling mode. As viewed locally at the RTU controller 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 controller 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

Setting for 0-10 VDC Actuator Setting for 2-10 VDC Actuator

0% 10% 20% 30% 40% 50% 60% 70% 80% 100%

0 to

20%

28% 36% 44% 52% 60% 68% 76% 84% 100%

- 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 controller will always compensate to find the proper required position to satisfy the current zone demand.

Air flow

Undersized VAV

Effective

Control

Area

Control

Area

Oversized VAV

% opening

- 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

Set to desired value

sequence

3 = On/Off Perimeter Reheat Only N/A AO2 not used by this reheat

Set to desired value

sequence 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 controllers are compatible with the new Viconics PIR (Passive Infra Red) cover accessory. Controllers 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 controllers 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.

In order for the PIR logic function to be enabled, the following settings must be enabled at the zone controller.

- If a local PIR cover is used, be sure to set the (

- If a remote PIR sensor is used on BI1, be sure to set the (BI1) parameter to Motion NO or Motion

PIR Func) parameter to ON.

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 Initial movement detected by the controller ( PIR cover or remote PIR )

Stand-by

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 controller will resume the stand-by mode.

2 H) AI4 CO2 / Other Sensor Input Operation

AI4 CO2 Sensor Input Operation

The VT76XXE controller features a 0-10VDC input (AI4) that is used for monitoring using any 0-10VDC sensor or to control the building CO

level.

Using any 0-10VDC value for monitoring

If the AI4 input is used for monitoring purposes only (even if monitoring CO parameter should be set to

None (not CO

with a CO2 sensor), the AI4

The value of the AI4 input can then be monitored at the network level (BACnet™ front end) under:

- AI4 value BACnet™ object (in VDC)

Locally at the controller, the value of AI4 can only be obtained by measuring the voltage between Scom and AI4 using a voltmeter. The value of AI4, if AI4 parameter is set to

None, will not be displayed on the

controller’s screen at any time.

Using a 0-10VDC CO2 sensor for control purposes

If the AI4 input is used with a CO

. In this case, a CO2 value will be displayed at the end of the configuration parameters list showing the

level measured by the sensor in ppm (particles per minute).

sensor for control purposes, the AI4 parameter should be then set to

The value of the AI4 input will also be displayed at the network level under:

- Room CO

Value BACnet™ object (in ppm)

- AI4 value BACnet™ object (in VDC)

When AI4 parameter is configured to CO VT76XXE will use these CO

values to determine the building’s CO2 Level for the IAQ control sequence.

, the CO

control is enabled only in Occupied mode. The

The following example shows the value of the BACnet™ objects as well as the values at the local controllers based on the AI4 parameter setting and Occupancy status. The example uses a 0 – 2000ppm

sensor with a signal of 0-10VDC.

AI4

parameter

None Occupied

CO2 Occupied

None Unoccupied

CO2 Unoccupied

Occupancy Sensor Voltage CO2 display at

local controller

5.0VDC No 0ppm 0ppm

5.0VDC Yes 1000ppm 1000ppm

5.0VDC No 0ppm 0ppm

5.0VDC Yes 1000ppm 0ppm

Room CO2

Value

Transferred

CO2 value

2 I) Disable Minimum Position parameter

The VZ7260 zone controllers feature the DisMinPo (Disable Minimum Position) parameter that is used to enable/disable the minimum damper’s minimum position parameter setting if the zone sequence (heat/cool) is different than the controller’s demand (heat/cool). The goal of this parameter is to prevent overcooling or overheating of zones that have demands that differ from the general zone sequence due to the airflow through the damper opening (at the minimum position). Most often, the zones affected are the internal zones (not on perimeter) whose demands are ignored by the rooftop controller because they are not master zones (when it comes to cooling and heating weights). Here are examples showing how the DisMinPo parameter setting affects the airflow.

DisMinPo set to Enable (minimum position enabled)

Minimum Position parameter: Zone Sequence: Zone Demand:

Cool (cool supply air)

Heat

15%

Damper Position: 15%

DisMinPo set to Disable (minimum position disabled)

Minimum Position parameter: Zone Sequence: Zone Demand:

Cool (cool supply air)

Heat

15%

Damper Position: 0%

IMPORTANT: The DisMinPo parameter is only effective when the Zone Sequence and the zone demand

are different, here’s the table showing when this parameter is effective.

Zone Sequence Zone Demand DisMinPo effectiveness Damper Position

Cool Cool Effective Minimum Position Cool Heat Not Effective Closed Cool No Demand Effective Minimum Position Heat Cool Effective Minimum Position Heat Heat Not Effective Closed Heat No Demand Effective Minimum Position

2 J) Heating and Cooling Performances

The VZ7260 zone controllers also feature heating and cooling performance indexes that indicate the performance of the zone controller in the last 90 minutes period (1.5 hours). The performances are displayed at the end of the parameters list, as an average difference between the setpoint and the room temperature for the last 90 minutes.

Example:

If the heating performance index HT Perf displays 0.5°F, it means that the average difference between the heating setpoint and the room temperature for the last 90 minutes was 0.5°F.

Invalid Performance Indexes Values

The performance indexes will be unreliable (invalid) if one of the following happens:

- System mode is set to Off

- Zone demand change between heating and cooling

- Any setpoint change

- Occupancy status change

The invalid value will be displayed as a random value higher than 83.5°F (Imperial) or 46.0°C (Metric). To have a valid performance value, the controller has to be stable (no above changed) for 90 minutes.

3) RTU Controllers VZ7656X1000W 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 controllers which typically only use two position demand or non- demand logic to initialize heating and cooling functions, Viconics VZ7656X1000X 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 controller is linked with the operation of the attached zone controllers. Although the controller 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 controllers 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 controller can be summarized as follow:

Heating and cooling demand data is first exchanged from the ZN 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 )

Each voting controller 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 controller 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

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 controller will then forward data to the zone controllers:

• 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 controller.

- When this schedule output value is unoccupied (as shown on the RTU controller display), then the attached zones will be unoccupied mode.

- When this schedule output value is occupied (as shown on the per RTU controller 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 wireless network occupancy command. This will disable the local schedule occupancy function to the zones. The whole system and all attached zones can only be initiated at the RTU controller level. This is done by using the local user menu at the RTU controller 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 controller can have functions locked out for the local user. This can prevent unwanted inputs to the system as a whole when the RTU controllers are installed in public areas or when certain local user interface functions of the RTU 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.

VZ76 Controller 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

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.

Heat Lock = 75F

Overlap = 10F

Cool Lock = 65F

Outside Air Temperature

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.

Heat Lock = 72F

No Overlap

Cool Lock = 72F

Outside Air Temperature

Heat Lock = 70F

No Heat No Cool

5F deadband

Cool Lock = 75F

Outside Air Temperature

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

Lock and C Lock )

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

cooling).

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.

This will translate into two cooling and two heating cycle periods per hour.

. However, limiting the RTU heating or cooling throughput based on outdoor

(Default of 4 cycles per hour for both heating and

( H

3G) By-Pass Damper / VFD Control and Operation

The RTU controller has a built in static pressure control loop with an analog 0 to 10 VDC output that can be configured to control a by-pass damper or a variable frequency drive (VFD). 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 controller (terminal SP).

The type of pressure transducer used needs to be of voltage type (0 to 5 VDC) and have a 24 VAC halfbridge 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, and the setting of the pressure control type parameter SP Cntrl. For proper operation of the control loop, the static pressure control actuator or VFD need to be properly installed.

By-Pass Damper Operation:

- Control signal = 0 VDC = Static pressure by-pass damper fully closed = No air recirculation from supply to return

- Control signal = 10 VDC = Static pressure by-pass damper fully opened = Maximum air recirculation from supply to return

When the fan output is off (Terminal G), the static pressure control loop is off 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 stages 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 controller. The current static pressure value can be read at the RTU controller at any time by using the manual scroll function and displaying the pressure prompt.

Variable Frequency Drive Operation:

In this case the G fan output is used as an enable / disable output for the VFD.

The VFD should be configured to be reverse acting:

- Control signal = 0 VDC = VFD at high flow = Higher pressure.

- Control signal = 10 VDC = VFD at low flow = Lower pressure.

When the VFD is disabled (Terminal G is off), the static pressure control loop is off and the VFD output is at 0VDC. 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 VFD is enabled (Terminal G is on), the static pressure control loop is enabled and the VFD will modulate to maintain the desired static pressure set point according to the static pressure input reading at the RTU controller. The current static pressure value can be read at the RTU controller at any time by using the manual scroll function and displaying the pressure prompt.

3H) Minimum Supply Heat Temperature Control and Lockout

The VZ7656F1000W master controller features a minimum supply air temperature PI control loop that is used to prevent the supply air temperature from dropping below the Min SH (Minimum Supply Heat Temperature) parameter value.

This control sequence is only available in the

An outdoor temperature supply air lockout is also one of the VZ7656F1000W features. This lockout only affects the minimum supply heat control sequence. Room temperature control is not affected. The SH Lock is the parameter used to set the outdoor air temperature above which the minimum supply heat temperature control sequence is disabled.

Example 1: Outdoor Temperature: SH Lock: Minimum Supply Heat Temperature Control is

60°F

55°F

VZ7656F1000W modulating heat rooftop controller.

disabled

Example 2: Outdoor Temperature: SH Lock: Minimum Supply Heat Temperature Control is

55°F

50°F

enabled

3I) Indoor Air Quality Control & Operation

The fresh air damper can be controlled through more than one sequence to achieve different control strategies such as free cooling (economizer mode), minimum fresh air control and CO

level control. Here

are the control sequences available:

Note: For the sequences mentioned below, the following conditions must be met in order for the sequences to be performed as stated:

- Max Pos parameter value must be greater than Min Pos Parameter value.

- Mac CO

- Max FA parameter value must be greater than Min FA Parameter value.

Economizer Control Mode Only

parameter value must be greater than Min CO2 Parameter value.

If the fresh air damper is to be used only for free cooling purposes (economizer mode, without fresh air measurement station or CO

control), only the Min Pos parameter and the free cooling sequence will be

active.

The FA Range parameter should be set to 0 CFM. (Default Value = 0 CFM)

- Set the Chngstpt parameter to desired value which free cooling is enabled. (Default Value =

55°F)

If the outside air temperature is greater than the changeover setpoint, then normal mechanical cooling will be used. If the outside air temperature is less than or equal to the changeover setpoint, then free cooling will be enabled and mechanical cooling stages will be locked out.

Economizer Mode and Fresh Air Measurement Station

If the fresh air damper is to be used for both free cooling and minimum fresh air volume control (economizer mode and fresh air measurement station, but without CO parameter and the free cooling sequence will be active.

level control), only the Min FA

- The FA Range parameter should be set to a value higher than 0 CFM (0 CFM disables the

fresh air control).

- Min FA (minimum fresh air) parameter should be set to the desired level.

The FA Range parameter value should be set to the maximum capacity of the fresh air measurement station. Therefore the relationship between air volumes and input signals can be established. For example, if the fresh air station capacity is 10000 CFM, set FA Range to 10000.

This will set the relationship of

0 VDC = 0 CFM and 10VDC = 10000 CFM.

Economizer Mode and CO2 Level Control

If the fresh air damper is to be used for both free cooling and CO level control, but without fresh air measurement station), only the Min Pos, Max Pos, Min CO2and Max CO2 parameters as well as the free cooling sequence will be active.

The FA Range parameter should be set to 0 CFM.

- Set AI4 parameter to CO

- Min Pos, Max Pos, Min CO

(0 VDC = 0ppm ; 10VDC = 2000ppm)

and Max CO2 parameters should be set according to the required

setting.

level control (economizer mode and CO

Max Pos

Current Fresh Air Damper Position

Min Pos

Min CO

Max CO

Current

Level

The higher value between free cooling output and interpolation output between the above graphic will be the signal sent to the fresh air damper.

Economizer Mode, CO2 Level Control and Fresh Air Measurement Station

If the fresh air damper is to be used for both free cooling and CO measurement station, only the Min FA, Max FA, Min CO

and Max CO2 parameters as well as the free

cooling sequence will be active.

The FA Range parameter should be set to something other than 0 CFM.

- Use an air flow transmitter to read fresh air level with AI2 input (0-5 VDC input)

- Min FA, Max FA, Min CO

setting.

and Max CO2 parameters should be set according to the required

level control with a fresh air

Max FA Setpoint

Current Fresh Air

oint

Set

Min FA Setpoint

Max CO

Min CO

Current

Level

The higher value between free cooling output and interpolation output based on the above graphic will be the signal sent to the fresh air damper. If the occupancy is unoccupied, then the CO 0%.

control output will be

4) Wireless Communication Overview

The Viconics VZ7260X5x00W and VZ7656X1000W controllers, Viconics Wireless Gateway (VWG) and Jace-driver and other related wireless controller 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 controller for sufficient for communication and no external communication is required. In this layout, the VZ76xx RTU controller acts as the network coordinator.

• The Viconics Wireless Gateway (VWG / Jace-Driver for 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.

(SA) Stand-Alone applications: Where zoning system(s) are self

(NS) Networked Systems applications: Where

4A) (SA) Stand-Alone applications

When PAN ID is used with a range of 251 to 500, for (SA) Stand-Alone Systems.

In this application, the VZ76xx controller(s) act as the coordinators to their own system. I.E. they are the network masters for each VZ72xx controller reporting to them when the whole zoning system(s) is self sufficient and communication and no external communication is required.

• Wireless controller factory default Channel and PAN ID = Controller(s) offline

• VZ76xx RTU controller is the network coordinator

• Range of PAN ID on all controllers to use 251 to 500. This range is reserved for stand-alone system

operation

Examples:

System 1

RTU VZ76 Coordinator

Channel 25 ID

200

Zone VZ72 Router Channel 25 ID

200

Zone VZ72 Router Channel 25 ID

200

Zone VZ72 Rou ter Channel 25 ID

200

Zone VZ72 Rou ter Channel 25 ID

200

System 2

RTU VZ76 Coordinator

Channel 25 ID

205

Zone VZ72 Router Channel 25 ID

205

Zone VZ72 Router Channel 25 ID

205

Zone VZ72 Router Channel 25 ID

205

Zone VZ72 Rou ter Channel 25 ID

205

Notes:

· Each system with a VZ76xx RTU master will use a unique PAN ID and or channel settings

4B) (NS) Networked System applications

When PAN ID is used with a range of 1 to 250, for (NS) Networked Systems.

In this application, any controller(s) are simply routers to the system. The VWG and Jace-driver is the coordinators to the system. The VWG and Jace-driver are the network masters for any controller(s) reporting to them, where zoning system(s) are required to communicate and exchange data points with the Viconics VWG and Jace-driver set. (More than one can be installed in a typical building application).

· Wireless controller factory default channel and PAN ID = Controller(s) offline

· VWG Jace-Driver is the network coordinator

· Any controllers (VZ72’s, VZ76xx RTU’s or any VT7xxx wireless controllers) act as routers.

· Range of PAN ID on all controllers to use 1 to 250. Reserved for networked system operation.

Examples:

Coordinator Channel 25 ID

200

System 1

RTU VZ76 Router

Channel 25 ID

200

Zone VZ72 Router Channel 25 ID

200

Zone VZ72 Router Channel 25 ID

200

Zone VZ72 Router Channel 25 ID

200

Zone VZ72 Router Channel 25 ID

200

System 2

RTU VZ76 Router

Channel 25 ID

200

Zone VZ72 Router Channel 25 ID

200

Zone VZ72 Router Channel 25 ID

200

Zone VZ72 Router Channel 25 ID

200

Zone VZ72 Router Channel 25 ID

200

Note:

· Each controller(s) uses the same PAN ID and channel as VWG Jace-Driver coordinator.

VWG and Jace-driver supports network integration for required GUI and system status objects.

4C) Basic Initial Design and Deployment Considerations

Proper design considerations need to be addressed prior to the installation of a Viconics wireless zoning system.

1. To avoid network interference with 802.11 Wi-Fi devices in the 2.4GHz spectrum range, Viconics

recommends the use of 802.15.4 channels 15, 25 and 26 only. 802.11 Wi-Fi transmissions overlap and may interfere with other channel selections allowed by 802.15.4 (Channels 11 to 14 & 16 to 24)

2. The maximum distance between each controller node should be 100 feet (30 M) or less between two

controller nodes. (Clear line of sight).

Open clear line of sight distance between 2 nodes should be a maximum of 100 feet ( 30 M )

• Non line of sight should be less than 50 feet (15M). Typical gypsum wall partitions made with metal stud frame construction.

Non line of sight maximum distance for typical gypsum wall partitions should be maximum of 30 feet between 2-thermostat nodes

( 10 M )

( 15 M )

)

3. Ensure that the minimum distance between any Viconics node and any Wi-Fi devices (wireless routers, wireless adapters, lap-tops using wireless networks, etc….) to be at least 3 feet (1 M) and preferably 10 feet (3 M) or more.

Minimum 3 feet (1 M)

between Wi-Fi

equipment and

Viconics wireless

Preferably 10 feet (3

M) or more between

Wi-Fi equipment and

Viconics wireless

4. Ensure that at least one controller is within 30 feet of the coordinator (VZ76xx for (SA) or VWG and Jace-Driver for (NS)) for every cluster of 10 VZ72xx zone controllers installed.

5. When possible, always try to locate the coordinator (VZ76xx for (SA) or VWG and Jace-driver for (NS)) near the center of all associated VZ72xx zone controllers installed.

6. Always try to locate the coordinator (VZ76xx for (SA) or VWG and Jace-driver for (NS)) near or in the line of sight to as many wireless controllers as possible.

7. Try to avoid metal, brick walls or concrete obstructions between wireless devices when possible.

8. For a 30 wireless controllers installation. A minimum of three of them should be within 30 feet or 9 Meters of the coordinator (VZ76xx for (SA) or VWG and Jace-Driver for (NS)) range.

30 feet (9 M

Coordinator

4D) Communication status LED and Troubleshooting

Each controller has a communication status service LED for troubleshooting purposes. Monitoring this LED will determine the network condition for each individual device and will tell you if they are successfully communicating with their peers on the network.

VZ76xx Adapter LED Status Indicators

(SA) Stand-Alone applications. When a PAN ID is used with a range of 1 to 250, for (SA) or Stand-Alone Systems

applications where the VZ76xx is used as a coordinator

1 x 200ms short blink 2 x 200ms short blinks

3 x 200ms short blinks

4 x 200ms short blinks 4 x 200ms short blinks and

1 x 1500ms long blink 4 x 200ms short blinks and

1 x 1500ms long blink and 1 x 3000ms long blink

Power on Power on Communicating with controller base Power on Communicating with controller base Valid Pan ID & Channel Not Used Power on Card memory initialized properly Communicating with controller

Wireless networks started successfully

Power on Card memory initialized properly Communicating with controller

Wireless networks started successfully

Wireless communication with VZ72 Zone controllers active

VZ76 Adapter LED Status Indicators

(NS) Networked System applications. When PAN ID is used with a range of 1 to 250, for (NS) or Networked

Systems applications where the VWG and Jace-Driver is used as a coordinator

1 x 200ms short blink 2 x 200ms short blinks

3 x 200ms short blinks

4 x 200ms short blinks

4 x 200ms short blinks and

1 x 1500ms long blink

4 x 200ms short blinks and

1 x 1500ms long blink and 1 x 3000ms long blink

The long 3000ms status flag is simply enabled by VZ72xx zone controllers reporting PI demand value to the VZ76 RTU controller. As long as a single VZ72xx zone controller is registered at the VZ76xx RTU, the long 3000ms status flag will be enabled

If the long 3000ms status flag indicating communication with the VZ7xx wireless zones controller is disabled after one minute; the ComLost alarm flag will be displayed at the VZ76xx RTU controller.

Power on Power on Communicating with controller base Power on Communicating with controller There is connectivity to wireless network Power on Communicating with controller There is connectivity to wireless network VWG / Jace-Driver is communicating with Wireless controller Power on Communicating with controller There is connectivity to wireless network

VWG / Jace-Driver is communicating with Wireless controller is also added to the VWG / Jace-Drive database

Power on Communicating with controller There is connectivity to wireless network

VWG / Jace-Driver is communicating with Wireless controller is also added to the VWG / Jace-Drive database Wireless communication with VZ72 Zone controllers active

VZ72 Adapter LED Status Indicators

1 x 200ms short blink 2 x 200ms short blinks

3 x 200ms short blinks

4 x 200ms short blinks

4 x 200ms short blinks and

1 x 1500ms long blink

4 x 200ms short blinks and

1 x 1500ms long blink and 1 x 3000ms long blink

Power on Power on Communicating with controller base Power on Communicating with controller There is connectivity to wireless network Power on Communicating with controller There is connectivity to wireless network VZ76 or VWG / Jace-Driver is communicating with Wireless controller Power on Communicating with controller There is connectivity to wireless network

VWG / Jace-Driver is communicating with Wireless controller is also added to the VWG / Jace-Drive database

Power on Communicating with controller There is connectivity to wireless network

VWG / Jace-Driver is communicating with Wireless controller is also added to the VWG / Jace-Drive database Wireless communication with VZ76 RTU controllers active

The 3000ms status flag is enabled when the VZ72xx zone controller successfully reads the required functional data points from its attached master VZ76xx RTU controller: Occupancy, Outdoor temperature, zone sequence, etc….

5) System Commissioning

If proper system operation is expected, then proper system commissioning should be done at all levels.

A zoning system has a huge dependency on the demand and response being fully functional both at the RTU and the zone level.

5A) Proper Commissioning of the Zone Controllers

At the zone level, care should be taken to insure that the following criteria(s) are met:

- Proper sizing of the VAV zone damper and the design of the air distribution system to insure that

peak load demands can be meet when the RTU delivers the capacity.

- VAV Damper operation. Insure that the VAV damper blade can rotate completely without any

mechanical limits as those are set by the controller parameters.

- Make sure the DA/RA setting of the VAV actuator is not set reversed. If improperly set it will result

in a zone that can never be satisfied and a demand to the RTU that will always be present if the zone is a master zone.

- Min, Max and HeatMax flow must be set during balancing. Also, adjustments may need to be done

to the main trunk side-take-off balancing damper if the local VAV trunk is equipped with one.

- Proper setup of the following important configuration parameters: Reheat lockouts, set point limits,

user interface lockout and demand weight adjustments to the RTU. All of these need to be properly evaluated and set according to the specifics of the installation.

- Addressing of both the MAC zone numbers to a specific RTU controller needs to be planned prior

to the installation.

5B) Proper Commissioning RTU Controllers

RTU level, care should be applied to insure the following conditions are met:

At the

- Proper sizing of the RTU heating and cooling capacity to insure it will meet the highest

instantaneous peak loads of the areas deserved by the system.

- Proper strategy and system layout of the mechanical system architecture.

- Proper commissioning and verification of the by-pass system. A wrongly configured by-pass

system may cause all the zones in a section of the system unable to get the proper RTU capacity down to the zones. Even when all of the zones are properly commissioned and all equipment are properly sized.

- Proper setup of the configuration parameters: Heating lockout, cooling lockout, control type

strategy, discharge air low and high limits, static pressure sensor range and static pressure setpoint. All of these need to be properly evaluated and set according to the specifications of the installation.

- Proper verification of RTU I/O operation including the RTU on board economizer operation.

5C) Operational System Checklist

It is recommended to keep a checklist of all milestones and configuration settings during start-up. This list should be kept as a reference with the system when it is fully commissioned. The following is only provided as a guideline template but can be extremely helpful for servicing issues and questions.

RTU Unit

Manufacturer: Serial number Model number: Year of manufacture Location: Date of original installation Cooling tonnage: Cooling number of stages: Heating capacity: Heating number of stages: Maximum CFMs: Total number of zones:

RTU Configuration, critical operational configuration parameters are in bold RTC MAC

RTC Baud PAN ID Channel

cal OS H stage

TOccTime cal RS

Lockout C stage Pwr del

H Lock CntrlTyp C Lock Dis HL Dis LL

2/4event

Aux cont Anticycl Prog rec Heat cph Occ CL Cool cph Occ HT Deadband Unocc CL Units Unocc HT Fan del BI 1

RTU Local Schedule Settings

Occupied day? 1 Monday Tuesday Wednesday Thursday Friday Saturday Sunday

Occ event 2

Sp range

Pressure

Unocc event 3

2 events

Occ event 4th Unocc event

4 events

RTC Baud refers to BACnet models only PAN ID and Channel refers to Wireless models only

RTU Commissioning

RTU mechanical cooling functional verification done Maximum Delta temperature ( return to supply temp ) for cooling stage #1: Maximum Delta temperature ( return to supply temp ) for cooling stage #1 & 2: Economizer cooling functional verification done Minimum position of economizer properly set? RTU controller Aux output used to disable minimum position of economizer check ? RTU heating functional verification done Maximum Delta temperature ( return to supply temp ) for heating stage #1: Maximum Delta temperature ( return to supply temp ) for heating stage #1 & 2: Static pressure transducer input reading fan Off ( should be 0 “WC or 0 PA ): Maximum static pressure transducer input reading fan On ( all VAV closed ): Static pressure damper actuator properly rigged and verified? Important configuration property set?

- RTC MAC value:

- PAN ID

- Channel

- CntrlTyp:

- Dis HL:

- Dis LL:

- H Lock:

- C Lock:

- Sp range:

- Pressure:

Communication with zones is active? ( Status LED & manual scroll display ) Local time clock set? Local schedule set? Local system mode set to Auto? ( System On ) Outdoor air sensor properly connected and displaying value? ( manual scroll display ) Supply air sensor properly connected and displaying value? ( manual scroll display ) Return air sensor properly connected and displaying value? ( manual scroll display )

Zone Number ( ) , use MAC address for zone name and repeat for ALL other zones

Location: Date of original installation VAV inlet diameter Ǿ in Inches: Zone vocation and use: Perimeter zone? VAV actuator brand: Internal zone? VAV actuator model: Type of reheat if installed: Capacity of reheat if installed:

Zone Configuration, critical operational configuration parameters are in bold Zone MAC PAN ID Channel RTC MAC

Get From Set Type MenuScro TOccTime C or F PIR Func

St-By HT St-By CL

Lockout Heat max

BI1

RehtConf

AO2RA/DA

AO2 OALK BO5 OALK

BO5 Time BO5 cont

Items in bold items are critical for proper system operation.

Unocc HT

Unocc CL

Cal RS

Deadband

Cool min

Min Pos

Max Pos

MaxHTPos

PIHT Wei

PICL Wei

Zone Number ( ) Commissioning

VAV damper actuator properly rigged and verified? ( opens and closes with demand ) Proper adjustments of zone side take off balancing damper? Proper balancing of zone minimum position? CFM = Proper balancing of zone maximum position? CFM = Proper balancing of zone MaxHeatflow position? (If reheat is used) CFM = Verification of Reheat (If reheat is used) Maximum Delta temperature of Reheat (If duct reheat is used) Important configuration property set ?

- Zone MAC:

- PAN ID

- Channel

- RTC MAC:

- Lockout:

- RehtConf: If reheat is used

- AO2 OALK: If reheat is used

- BO5 OALK: If reheat is used

- Heat max:

- Cool min:

- Min Pos:

- Max Pos:

- MaxHTPos:

- PIHT Wei:

- PICL Wei:

Communication with RTU is active? ( Status LED & outdoor temperature display )

Bold items are critical for proper system operation

Is this zone a master in heating? Is this zone a master in heating?

6) Things You Need to Know

6A) Single 24 VAC Zone Transformer vs. Multi 24 VAC Zone Transformers

It is possible to use a single 24 VAC transformer for each zone controller or you may use a single large central 24 VAC transformer for many zone controllers.

If using a single 24 VAC for each zone controller.

- Use a 20 VA or more Class2 self protected transformer to power all components attached to the zone controller.

- Be sure to respect the polarity of all components in the circuit: analog VAV actuator, analog reheat, etc…

- Be sure that if a ground is required, the common side of the circuit is the one connected to earth (0 V ~ Com). Grounding is required only at one location to prevent ground loops.

If using a large central 24 VAC transformer for many zones.

- If using Class1 unprotected transformer to power all components attached to the ZN controller. Be sure that the installed fuse or circuit protection is sized according to the maximum installed required current load. This is not necessarily the same as the maximum current available from the transformer. Ex.: If a 100 VA transformer is installed and the maximum installed load is 45 VA for all devices attached, then the fused value should be 2 amps maximum at 24 VAC.

- Be sure to respect the polarity of all components in the circuit: All analog VAV actuator(s), all analog reheat devices, etc…

- Be sure that if grounded is required, the common side of the circuit is the one connected to earth (0 V ~ Com) Grounding is required only at one location to prevent ground loops.

6B) Critical Point Checks

To insure proper and reliable operation of the system, it is the responsibility of the system designer or installer to properly verify all important milestones of the project

This includes all other contractual aspects for the system performed outside of the control system scope of work:

- Design phase: load calculations and ductwork layout and sizing, equipment selection, etc…..

- Construction phase: RTU installation, ductwork installation, electrical work required, etc…

- Commissioning and delivery phase: Operational system checklist, balancing, proper RTU

commissioning, etc….

In order to successfully deliver a fully functional system that will keep customer happy, proper initial design and proper commissioning are mandatory.

6C) Balancing and Capacity

It is not the mandate of a zoning control system to correct for an incorrect mechanical layout or improper load calculations of the mechanical zoning equipment. The control system will deliver the loads required by the master demanding zones by appropriately distributing the total available capacity of the installed equipment to the required demanding zones.

It should also be noted that even when the equipment is undersized, the control system will distribute the available capacity according to the priorities requested making most of the areas comfortable.

However, proper air balancing of the main trunks and zones must be done for optimal system operation. This includes the following:

- Min, Max and HeatMaxflow properly adjusted during balancing.

- Adjustments may need to be done to the main trunk side-take-off directional adjustment blade of

the local VAV trunk is equipped with one.

Viconics VWZS Application Guide

Specifications and Main Features

Frequently Asked Questions

User Manual

Please refer to the following Viconics documents for detailed information and design guidelines for the wireless zoning system version:

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:

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

(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.

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

VZ76xx Adapter LED Status Indicators

VZ76 Adapter LED Status Indicators