Demand Controlled Ventilation in the Tracker BMTK / CCP III System Using CO2 Levels

Issue:

Demand Controlled Ventilation in the Tracker BMTK / CCP III System Using CO2 Levels

Resolution:

 

From CCP operation page 22, VAV-SVU01A-EN: 

CO2-Based Demand Controlled Ventilation

The VariTrac CCP demand-control ventilation program resets the ventilation damper position for the Voyager/Reliatel unit based on the zone CO2 level. The setup is found under the Panel setup menu in VariTrac software. 

 The program has four configuration settings:

CO2 normal level (ppm)

Minimum ventilation damper position (%)

CO2 peak level (ppm)

Maximum ventilation damper position (%)

As the zone CO2 level rises from the normal level to the peak level, the damper position is reset linearly between the minimum damper position and the maximum damper position. CO2 sensors may now be connected to VariTrac zone UCMs Version 4.0 or greater. The zone CO2 concentration is communicated from the zone UCM to the CCP. The program can be configured to use one zone CO2 sensor as its source, or it can be configured to hunt through all zones with sensors attached and use the highest value. If the VariTrac system is controlling a non-communicating HVAC unit with the optional relay board, the spare binary output on the relay board can be configured for CO2 control. In this configuration, the program will energize the relay when the peak CO2 level is reached and de-energize the relay when the CO2 concentration returns to the normal level.

 

 

If the CO2 sensor is wired to the Voyager/ReliaTel, the rooftop will want to control the outdoor air damper to maintain the CO2 setpoint as set by a potentiometer on the Voyager, but you can't change the setpoint or see the CO2 level from the CCPIII and the CCP will actually send down a minimum airflow setting which disables rooftop demand ventilation. 

 

RTRM version 8 and newer disables local DCV if the system sends a local minimum position.  Since the minimum position cannot be set to local in the CCP (It has an editable value), it will always send a minimum position thus disabling local DCV.

 

 If a CO2 sensor is wired to a VAV UCM, the sensor on the Voyager is ignored.

 

Notes:

 

Changes:

 

Other Question/Problem/Cause Statements:

• Demand Controlled Ventilation in the Tracker BMTK / CCP III System Using CO2 Levels
• Is it possible to do demand controlled ventilation with a Tracker BMTK / CCP III system?
• Where can I install the CO2 sensor for demand control ventilation on a Voyager?
• How does the CCP3 do Demand Controlled Ventilation?

Facts:

• Tracker BMTK
• VariTrac III Central Control Panel (CCP)

Original wave: wave3296